- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:13:06 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 306757, Seg_Num: 0
GRB_RA: 217.926d {+14h 31m 42s} (J2000),
218.010d {+14h 32m 02s} (current),
217.411d {+14h 29m 39s} (1950)
GRB_DEC: +36.303d {+36d 18' 10"} (J2000),
+36.267d {+36d 16' 01"} (current),
+36.523d {+36d 31' 24"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 18756 [cnts] Image_Peak=1909 [image_cnts]
TRIGGER_DUR: 1.024 [sec]
TRIGGER_INDEX: 155 E_range: 50-350 keV
BKG_INTEN: 33657 [cnts]
BKG_TIME: 22357.34 SOD {06:12:37.34} UT
BKG_DUR: 8 [sec]
GRB_DATE: 14544 TJD; 79 DOY; 08/03/19
GRB_TIME: 22369.25 SOD {06:12:49.25} UT
GRB_PHI: 0.83 [deg]
GRB_THETA: 11.73 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 206.72 [sigma]
IMAGE_SIGNIF: 22.50 [sigma]
MERIT_PARAMS: +1 +0 +0 +0 +3 +34 +0 +0 +63 +1
SUN_POSTN: 359.10d {+23h 56m 24s} -0.39d {-00d 23' 26"}
SUN_DIST: 129.15 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.31d {+10h 05m 14s} +11.50d {+11d 30' 02"}
MOON_DIST: 64.51 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 199.01, 47.75 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Coordinates.
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
COMMENTS: This trigger occurred at longitude,latitude = 276.64,20.21 [deg].
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:14:16 UT
NOTICE_TYPE: Swift-XRT Position
TRIGGER_NUM: 306757, Seg_Num: 0
GRB_RA: 217.9196d {+14h 31m 40.7s} (J2000),
218.0042d {+14h 32m 01.0s} (current),
217.4046d {+14h 29m 37.0s} (1950)
GRB_DEC: +36.3041d {+36d 18' 14.7"} (J2000),
+36.2680d {+36d 16' 04.9"} (current),
+36.5245d {+36d 31' 28.1"} (1950)
GRB_ERROR: 4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 1.56e-07 [erg/cm2/sec]
GRB_SIGNIF: 12.52 [sigma]
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22429.72 SOD {06:13:49.72} UT, 60.5 [sec] since BAT Trigger Time
TAM[0-3]: 327.66 237.25 261.51 243.63
AMPLIFIER: 2
WAVEFORM: 134
SUN_POSTN: 359.10d {+23h 56m 24s} -0.39d {-00d 23' 25"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.32d {+10h 05m 16s} +11.50d {+11d 29' 45"}
MOON_DIST: 64.50 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.55, 66.88 [deg] galactic lon,lat of the burst
ECL_COORDS: 199.00, 47.75 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: The object found at this position is either a very bright burst or a cosmic ray hit.
COMMENTS: Examine the XRT Image to differentiate (CRs are much more compact); see examples at:
COMMENTS: http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:14:26 UT
NOTICE_TYPE: Swift-XRT Image
TRIGGER_NUM: 306757, Seg_Num: 0
GRB_RA: 217.9196d {+14h 31m 40.7s} (J2000),
218.0042d {+14h 32m 01.0s} (current),
217.4046d {+14h 29m 37.0s} (1950)
GRB_DEC: +36.3041d {+36d 18' 14.7"} (J2000),
+36.2680d {+36d 16' 04.9"} (current),
+36.5245d {+36d 31' 28.1"} (1950)
GRB_ERROR: 4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN: 157 [cnts]
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22429.72 SOD {06:13:49.72} UT, 60.5 [sec] since BAT Trigger Time
CENTROID_X: 295.13, raw= 295 [pixels]
CENTROID_Y: 301.76, raw= 302 [pixels]
ROLL: 53.98 [deg]
GAIN: 2
MODE: 2, Short Image mode
WAVEFORM: 134
EXPO_TIME: 0.10 [sec]
GRB_POS_XRT_Y: 8.87
GRB_POS_XRT_Z: -16.89
MAGE_URL: sw00306757000msxps_rw.img
SUN_POSTN: 359.10d {+23h 56m 24s} -0.39d {-00d 23' 25"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.32d {+10h 05m 17s} +11.50d {+11d 29' 43"}
MOON_DIST: 64.49 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.55, 66.88 [deg] galactic lon,lat of the burst
ECL_COORDS: 199.00, 47.75 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:14:33 UT
NOTICE_TYPE: Swift-XRT Processed Image
TRIGGER_NUM: 306757, Seg_Num: 0
GRB_RA: 217.9196d {+14h 31m 40.7s} (J2000),
218.0042d {+14h 32m 01.0s} (current),
217.4046d {+14h 29m 37.0s} (1950)
GRB_DEC: +36.3041d {+36d 18' 14.7"} (J2000),
+36.2680d {+36d 16' 04.9"} (current),
+36.5245d {+36d 31' 28.1"} (1950)
GRB_ERROR: 4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN: 157 [cnts]
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22429.72 SOD {06:13:49.72} UT, 60.5 [sec] since BAT Trigger Time
CENTROID_X: 295.13, raw= 295 [pixels]
CENTROID_Y: 301.76, raw= 302 [pixels]
ROLL: 53.98 [deg]
GAIN: 2
MODE: 2, Short Image mode
WAVEFORM: 134
EXPO_TIME: 0.10 [sec]
GRB_POS_XRT_Y: 8.87
GRB_POS_XRT_Z: -16.89
IMAGE_URL: sw00306757000msxps_rw.img
SUN_POSTN: 359.10d {+23h 56m 24s} -0.39d {-00d 23' 25"}
SUN_POSTN: 359.10d {+23h 56m 24s} -0.39d {-00d 23' 25"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.32d {+10h 05m 17s} +11.49d {+11d 29' 41"}
MOON_DIST: 64.49 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.55, 66.88 [deg] galactic lon,lat of the burst
ECL_COORDS: 199.00, 47.75 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Processed Image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:36:30 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.299d {+36d 17' 58"} (J2000)
POINT_ROLL: 53.982d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 23343.21 SOD {06:29:03.21} UT, 974.0 [sec] since BAT Trigger Time
FILTER: 3, V
BKG_MEAN: 1.130
N_STARS: 34
X_OFFSET: 497 [pixels]
Y_OFFSET: 523 [pixels]
X_MAX: 1456 [pixels]
Y_MAX: 1482 [pixels]
DET_THRESH: 9
PHOTO_THRESH: 4
SL_URL: sw00306757000msufc0973.fits
SUN_POSTN: 359.11d {+23h 56m 27s} -0.38d {-00d 23' 03"}
SUN_DIST: 129.17 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.50d {+10h 06m 01s} +11.41d {+11d 24' 30"}
MOON_DIST: 64.39 [deg]
MOON_ILLUM: 94 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Source List.
COMMENTS: All 4 attachments are included.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:25:33 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.299d {+36d 17' 57"} (J2000)
ROLL: 53.983d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22544.18 SOD {06:15:44.18} UT, 174.9 [sec] since BAT Trigger Time
FILTER: 3, V
EXPOSURE_ID: 227600146
X_OFFSET: 817 [pixels]
Y_OFFSET: 843 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 977
Y_GRB_POS: 1003
BINNING_INDEX: 1
IM_URL: sw00306757000msuni0174.fits
SUN_POSTN: 359.11d {+23h 56m 25s} -0.39d {-00d 23' 14"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.41d {+10h 05m 39s} +11.45d {+11d 27' 05"}
MOON_DIST: 64.44 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Image.
COMMENTS: The GRB Position came from the XRT Position Command.
COMMENTS: The image has 2x2 binning (compression).
COMMENTS: If you have elected to receive attachments:
COMMENTS: The uvot_sources_image.fits.gz file does not exist; skipping the attachment.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:30:55 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.300d {+36d 17' 58"} (J2000)
ROLL: 53.983d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 23237.23 SOD {06:27:17.23} UT, 868.0 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 227600839
X_OFFSET: 816 [pixels]
Y_OFFSET: 842 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 976
Y_GRB_POS: 1002
BINNING_INDEX: 1
IM_URL: sw00306757000msuni0867.fits
SUN_POSTN: 359.11d {+23h 56m 26s} -0.39d {-00d 23' 09"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.46d {+10h 05m 50s} +11.43d {+11d 25' 49"}
MOON_DIST: 64.42 [deg]
MOON_ILLUM: 94 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Image.
COMMENTS: The GRB Position came from the Window Position in the Mode Command.
COMMENTS: The image has 2x2 binning (compression).
COMMENTS: If you have elected to receive attachments:
COMMENTS: The uvot_sources_image.fits.gz file does not exist; skipping the attachment.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:24:17 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.299d {+36d 17' 57"} (J2000)
POINT_ROLL: 53.983d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22544.18 SOD {06:15:44.18} UT, 174.9 [sec] since BAT Trigger Time
FILTER: 3, V
BKG_MEAN: 1.094
N_STARS: 63
X_OFFSET: 497 [pixels]
Y_OFFSET: 523 [pixels]
X_MAX: 1456 [pixels]
Y_MAX: 1482 [pixels]
DET_THRESH: 9
PHOTO_THRESH: 4
SL_URL: sw00306757000msufc0174.fits
SUN_POSTN: 359.11d {+23h 56m 25s} -0.39d {-00d 23' 15"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.40d {+10h 05m 36s} +11.46d {+11d 27' 23"}
MOON_DIST: 64.45 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Source List.
COMMENTS: All 4 attachments are included.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:34:44 UT
NOTICE_TYPE: Swift-UVOT Position
TRIGGER_NUM: 306757, Seg_Num: 0
GRB_RA: 217.9259d {+14h 31m 42.21s} (J2000),
218.0105d {+14h 32m 02.51s} (current),
217.4109d {+14h 29m 38.60s} (1950)
GRB_DEC: +36.3029d {+36d 18' 10.4"} (J2000),
+36.2669d {+36d 16' 00.6"} (current),
+36.5233d {+36d 31' 23.7"} (1950)
GRB_ERROR: 4.7 [arcsec radius, statistical only]
GRB_MAG: 11.50 +/- 1.00 [mag]
FILTER: 3, V
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22369.00 SOD {06:12:49.00} UT, 86399.8 [sec] since BAT Trigger Time
SUN_POSTN: 359.11d {+23h 56m 27s} -0.39d {-00d 23' 05"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.49d {+10h 05m 57s} +11.42d {+11d 24' 55"}
MOON_DIST: 64.41 [deg]
MOON_ILLUM: 94 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 199.01, 47.75 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT UVOT Position Notice.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: Saturated in UVOT.
COMMENTS: Position is uncertain
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:37:11 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.299d {+36d 17' 58"} (J2000)
ROLL: 53.982d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 23343.21 SOD {06:29:03.21} UT, 974.0 [sec] since BAT Trigger Time
FILTER: 3, V
EXPOSURE_ID: 227600945
X_OFFSET: 816 [pixels]
Y_OFFSET: 842 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 976
Y_GRB_POS: 1002
BINNING_INDEX: 1
IM_URL: sw00306757000msuni0973.fits
SUN_POSTN: 359.11d {+23h 56m 27s} -0.38d {-00d 23' 03"}
SUN_DIST: 129.17 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.51d {+10h 06m 02s} +11.41d {+11d 24' 20"}
MOON_DIST: 64.39 [deg]
MOON_ILLUM: 94 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Image.
COMMENTS: The GRB Position came from the Window Position in the Mode Command.
COMMENTS: The image has 2x2 binning (compression).
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:23:46 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.299d {+36d 17' 57"} (J2000)
POINT_ROLL: 53.983d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22544.18 SOD {06:15:44.18} UT, 174.9 [sec] since BAT Trigger Time
FILTER: 3, V
BKG_MEAN: 1.094
N_STARS: 63
X_OFFSET: 497 [pixels]
Y_OFFSET: 523 [pixels]
X_MAX: 1456 [pixels]
Y_MAX: 1482 [pixels]
DET_THRESH: 9
PHOTO_THRESH: 4
SL_URL: sw00306757000msufc0174.fits
SUN_POSTN: 359.10d {+23h 56m 25s} -0.39d {-00d 23' 16"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.40d {+10h 05m 35s} +11.46d {+11d 27' 31"}
MOON_DIST: 64.45 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:29:15 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.300d {+36d 17' 58"} (J2000)
POINT_ROLL: 53.983d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 23237.23 SOD {06:27:17.23} UT, 868.0 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 1.174
N_STARS: 33
X_OFFSET: 497 [pixels]
Y_OFFSET: 523 [pixels]
X_MAX: 1456 [pixels]
Y_MAX: 1482 [pixels]
DET_THRESH: 9
PHOTO_THRESH: 4
SL_URL: sw00306757000msufc0867.fits
SUN_POSTN: 359.11d {+23h 56m 26s} -0.39d {-00d 23' 10"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.44d {+10h 05m 46s} +11.44d {+11d 26' 13"}
MOON_DIST: 64.43 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:37:26 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.299d {+36d 17' 58"} (J2000)
ROLL: 53.982d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 23343.21 SOD {06:29:03.21} UT, 974.0 [sec] since BAT Trigger Time
FILTER: 3, V
EXPOSURE_ID: 227600945
X_OFFSET: 816 [pixels]
Y_OFFSET: 842 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 976
Y_GRB_POS: 1002
BINNING_INDEX: 1
IM_URL: sw00306757000msuni0973.fits
SUN_POSTN: 359.11d {+23h 56m 27s} -0.38d {-00d 23' 02"}
SUN_DIST: 129.17 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.51d {+10h 06m 03s} +11.40d {+11d 24' 17"}
MOON_DIST: 64.39 [deg]
MOON_ILLUM: 94 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Image.
COMMENTS: The GRB Position came from the Window Position in the Mode Command.
COMMENTS: The image has 2x2 binning (compression).
COMMENTS: If you have elected to receive attachments:
COMMENTS: The uvot_sources_image.fits.gz file does not exist; skipping the attachment.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:30:30 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.300d {+36d 17' 58"} (J2000)
ROLL: 53.983d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 23237.23 SOD {06:27:17.23} UT, 868.0 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 227600839
X_OFFSET: 816 [pixels]
Y_OFFSET: 842 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 976
Y_GRB_POS: 1002
BINNING_INDEX: 1
IM_URL: sw00306757000msuni0867.fits
SUN_POSTN: 359.11d {+23h 56m 26s} -0.39d {-00d 23' 09"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.45d {+10h 05m 49s} +11.43d {+11d 25' 55"}
MOON_DIST: 64.42 [deg]
MOON_ILLUM: 94 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Image.
COMMENTS: The GRB Position came from the Window Position in the Mode Command.
COMMENTS: The image has 2x2 binning (compression).
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:25:06 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.299d {+36d 17' 57"} (J2000)
ROLL: 53.983d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22544.18 SOD {06:15:44.18} UT, 174.9 [sec] since BAT Trigger Time
FILTER: 3, V
EXPOSURE_ID: 227600146
X_OFFSET: 817 [pixels]
Y_OFFSET: 843 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 977
Y_GRB_POS: 1003
BINNING_INDEX: 1
IM_URL: sw00306757000msuni0174.fits
SUN_POSTN: 359.11d {+23h 56m 25s} -0.39d {-00d 23' 15"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.41d {+10h 05m 38s} +11.45d {+11d 27' 12"}
MOON_DIST: 64.44 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Image.
COMMENTS: The GRB Position came from the XRT Position Command.
COMMENTS: The image has 2x2 binning (compression).
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:17:53 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.918d {+14h 31m 40s} (J2000)
POINT_DEC: +36.297d {+36d 17' 50"} (J2000)
ROLL: 53.985d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22438.20 SOD {06:13:58.20} UT, 69.0 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 227600040
X_OFFSET: 817 [pixels]
Y_OFFSET: 843 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 977
Y_GRB_POS: 1003
BINNING_INDEX: 1
IM_URL: sw00306757000msuni0068.fits
SUN_POSTN: 359.10d {+23h 56m 24s} -0.39d {-00d 23' 22"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.35d {+10h 05m 23s} +11.48d {+11d 28' 54"}
MOON_DIST: 64.48 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.53, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Image.
COMMENTS: The GRB Position came from the XRT Position Command.
COMMENTS: The image has 2x2 binning (compression).
COMMENTS: If you have elected to receive attachments:
COMMENTS: The uvot_sources_image.fits.gz file does not exist; skipping the attachment.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:17:33 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.918d {+14h 31m 40s} (J2000)
POINT_DEC: +36.297d {+36d 17' 50"} (J2000)
ROLL: 53.985d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22438.20 SOD {06:13:58.20} UT, 69.0 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 227600040
X_OFFSET: 817 [pixels]
Y_OFFSET: 843 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 977
Y_GRB_POS: 1003
BINNING_INDEX: 1
IM_URL: sw00306757000msuni0068.fits
SUN_POSTN: 359.10d {+23h 56m 24s} -0.39d {-00d 23' 22"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.35d {+10h 05m 23s} +11.48d {+11d 28' 59"}
MOON_DIST: 64.48 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.53, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Image.
COMMENTS: The GRB Position came from the XRT Position Command.
COMMENTS: The image has 2x2 binning (compression).
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:17:43 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 306757, Seg_Num: 0
GRB_RA: 217.926d {+14h 31m 42s} (J2000),
218.010d {+14h 32m 02s} (current),
217.411d {+14h 29m 39s} (1950)
GRB_DEC: +36.303d {+36d 18' 10"} (J2000),
+36.267d {+36d 16' 01"} (current),
+36.523d {+36d 31' 24"} (1950)
GRB_DATE: 14544 TJD; 79 DOY; 08/03/19
GRB_TIME: 22369.25 SOD {06:12:49.25} UT
TRIGGER_INDEX: 155
GRB_PHI: 0.83 [deg]
GRB_THETA: 11.73 [deg]
DELTA_TIME: -69.00 [sec]
TRIGGER_DUR: 1.024 [sec]
SOLN_STATUS: 0x3
RATE_SIGNIF: 206.72 [sigma]
IMAGE_SIGNIF: 22.50 [sigma]
LC_URL: sw00306757000msb.lc
SUN_POSTN: 359.10d {+23h 56m 24s} -0.39d {-00d 23' 22"}
SUN_DIST: 129.15 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.35d {+10h 05m 23s} +11.48d {+11d 28' 56"}
MOON_DIST: 64.48 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 199.01, 47.75 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Lightcurve.
COMMENTS:
COMMENTS: The next comments were copied from the BAT_POS Notice:
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
COMMENTS: This trigger occurred at longitude,latitude = 276.64,20.21 [deg].
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:16:44 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.918d {+14h 31m 40s} (J2000)
POINT_DEC: +36.297d {+36d 17' 50"} (J2000)
POINT_ROLL: 53.985d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22438.20 SOD {06:13:58.20} UT, 69.0 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 1.286
N_STARS: 142
X_OFFSET: 528 [pixels]
Y_OFFSET: 536 [pixels]
X_MAX: 1487 [pixels]
Y_MAX: 1495 [pixels]
DET_THRESH: 10
PHOTO_THRESH: 5
SL_URL: sw00306757000msufc0068.fits
SUN_POSTN: 359.10d {+23h 56m 24s} -0.39d {-00d 23' 23"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.34d {+10h 05m 21s} +11.49d {+11d 29' 10"}
MOON_DIST: 64.48 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.53, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Source List.
COMMENTS: All 4 attachments are included.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:16:05 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.918d {+14h 31m 40s} (J2000)
POINT_DEC: +36.297d {+36d 17' 50"} (J2000)
POINT_ROLL: 53.985d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 22438.20 SOD {06:13:58.20} UT, 69.0 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 1.286
N_STARS: 142
X_OFFSET: 528 [pixels]
Y_OFFSET: 536 [pixels]
X_MAX: 1487 [pixels]
Y_MAX: 1495 [pixels]
DET_THRESH: 10
PHOTO_THRESH: 5
SL_URL: sw00306757000msufc0068.fits
SUN_POSTN: 359.10d {+23h 56m 24s} -0.39d {-00d 23' 24"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.33d {+10h 05m 20s} +11.49d {+11d 29' 20"}
MOON_DIST: 64.49 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.53, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:29:36 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.300d {+36d 17' 58"} (J2000)
POINT_ROLL: 53.983d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 23237.23 SOD {06:27:17.23} UT, 868.0 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 1.174
N_STARS: 33
X_OFFSET: 497 [pixels]
Y_OFFSET: 523 [pixels]
X_MAX: 1456 [pixels]
Y_MAX: 1482 [pixels]
DET_THRESH: 9
PHOTO_THRESH: 4
SL_URL: sw00306757000msufc0867.fits
SUN_POSTN: 359.11d {+23h 56m 26s} -0.39d {-00d 23' 10"}
SUN_DIST: 129.16 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.45d {+10h 05m 47s} +11.44d {+11d 26' 08"}
MOON_DIST: 64.42 [deg]
MOON_ILLUM: 93 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Source List.
COMMENTS: All 4 attachments are included.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 19 Mar 08 06:36:03 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 306757, Seg_Num: 0
POINT_RA: 217.917d {+14h 31m 40s} (J2000)
POINT_DEC: +36.299d {+36d 17' 58"} (J2000)
POINT_ROLL: 53.982d
IMG_START_DATE: 14544 TJD; 79 DOY; 08/03/19
IMG_START_TIME: 23343.21 SOD {06:29:03.21} UT, 974.0 [sec] since BAT Trigger Time
FILTER: 3, V
BKG_MEAN: 1.130
N_STARS: 34
X_OFFSET: 497 [pixels]
Y_OFFSET: 523 [pixels]
X_MAX: 1456 [pixels]
Y_MAX: 1482 [pixels]
DET_THRESH: 9
PHOTO_THRESH: 4
SL_URL: sw00306757000msufc0973.fits
SUN_POSTN: 359.11d {+23h 56m 27s} -0.38d {-00d 23' 04"}
SUN_DIST: 129.17 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 151.50d {+10h 05m 60s} +11.41d {+11d 24' 36"}
MOON_DIST: 64.40 [deg]
MOON_ILLUM: 94 [%]
GAL_COORDS: 62.54, 66.88 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 199.00, 47.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN Circular #7427
J. L. Racusin (PSU), N. Gehrels (NASA/GSFC),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
C. B. Markwardt (CRESST/GSFC/UMD), C. Pagani (PSU),
D. M. Palmer (LANL) and M. Stamatikos (NASA/ORAU) report on behalf of
the Swift Team:
At 06:12:49 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080319B (trigger=306757). Swift slewed immediately to
the burst. The BAT on-board calculated location is
RA, Dec 217.926, +36.303 which is
RA(J2000) = 14h 31m 42s
Dec(J2000) = +36d 18' 10"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed one bright but
complex peak with a duration of about 50 sec, with an extended tail.
The peak count rate was ~70,000 counts/sec (15-350 keV), at ~20 sec
after the trigger.
The XRT began observing the field at 06:13:49.7 UT, 60.5 seconds after
the BAT trigger. XRT found a very bright fading, uncatalogued X-ray
source located at RA, Dec 217.9196, +36.3041 which is equivalent to:
RA(J2000) = 14h 31m 40.7s
Dec(J2000) = +36d 18' 14.7"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 18 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to assess possible
redshift constraints using X-ray spectroscopy and the nH-z relation
from Grupe et al. (2007).
UVOT took a finding chart exposure of 400 seconds with the V filter
starting 175 seconds after the BAT trigger. There is a candidate
afterglow in the rapidly available 2.7'x2.7' sub-image. This
position is consistent with the XRT error circle, but the source is
so bright that a precise UVOT position is not possible due to
saturation effects. The estimated magnitude is 11.5 with a 1-sigma
error of about 0.5 mag. No correction has been made for the expected
extinction of about 0.04 magnitudes.
Burst Advocate for this burst is J. L. Racusin (racusin AT astro.psu.edu).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
- GCN Circular #7428
S. T. Holland (CRESST/USRA/GSFC) and J. L. Racusin (PSU) reports on
behalf of the Swift/UVOT team:
The UVOT position of GRB 080319B (Racusin et al. 2008 GCN Circ.
7427) is
RA(J2000.0) = 14:31:40.98
Dec(J2000.0) = +36:18:08.8
with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence).
Please update my e-mail address in your Address Book to
Stephen.T.Holland@nasa.gov
- GCN Circular #7430
W. Li, J. S. Bloom, R. Chornock, R. Foley, D. A. Perley, and A. V. Filippenko,
University of California at Berkeley, on behalf of the KAIT GRB team, report:
KAIT responded to GRB 080319B (Swift trigger 306757) and was taking
images. There is a bright afterglow at position
RA = 14:31:40.97
DEC = +36:18:07.9
The measured magnitude is R = 15.4 at 06:49:07 UT.
This message can be cited.
- GCN Circular #7431
S. Covino, P. D'Avanzo, D. Fugazza, L.A. Antonelli, L. Calzoletti,
S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini, V. D'Elia, F.
D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C. Guidorzi, G.L.
Israel, E. Maiorano, N. Masetti, A. Melandri, E. Meurs, L. Nicastro,
E. Palazzi, E. Pian, S. Piranomonte, L. Stella, G. Stratta, G.
Tagliaferri, G. Tosti, V.Testa, S.D. Vergani, F. Vitali report on
behalf of the REM
team:
The robotic 60-cm REM telescope located at La Silla (Chile) observed
automatically the field of the GRB 080319B on March 19 06:13:32 UT
(about 43 seconds after the burst).
We clearly detect the afterglow reported in GCN 7427, 7428, 7430
(Racusin et
al.; Holland et al.; Li et al.).
The object was still at H~12.5 at about 22 min from the burst time.
Further analyses and observations are in progress.
- GCN Circular #7432
P. A. Milne (Steward Observatory) and G. G. Williams (MMTO), on behalf
of the Super-LOTIS Collaboration, report:
The robotic 0.6-m Super-LOTIS telescope began observing the error box
of GRB 080319B (Swift Trigger 306757, Racusin et al. GCN 7427) at
06:27:00.3 UT, 851 seconds after the trigger. We identify a bright
source consistent within the UVOT candidate.
Using the USNO-B1.0 star (1263-0223138) at RA=14:31:39.66,
Dec=+36:18:54.5 with R2MAG=14.98 as a reference, we estimate the
following R-band magnitude for the transient:
t_start (UT) exp t (s) t_start-t_0 (s) R Mag
----------------------------------------------------------------
06:27:00.3 60 851 R = 13.52 +/- 0.01
Additional observations and analysis are ongoing.
- GCN Circular #7433
R.J. Smith (Liverpool JMU), A. Gomboc (U. Ljubljana), N. Tanvir (Leicester) A.
Melandri, C.G. Mundell, I.A. Steele, S. Kobayashi, D. Bersier (Liverpool JMU)
report:
The 2-m Liverpool Telescope (La Palma) observed the position of
GRB 080319B (SWIFT trigger 306757) starting 30 min after the GRB trigger
time. We detect an optical afterglow candidate in r' filter at
14:31:41 +36:18:09 J2000 consistent with the uncatalogued source
visible in the UVOT data.
Filter t_mid (min from GRB) Tot_Exp (s) R
--------------------------------------------------------------
r' 30.64 120 14.9
r' 32.83 120 15.1
r' 35.02 120 15.2
-------------------------------------------------------------
Observations were performed in SDSS r' filter and
magnitudes calibrated vs R2 USNO-B1 magnitudes for a few selected stars.
No further observations were possible due to approaching twilight.
- GCN Circular #7434
J. S. Bloom, D. Starr, and D. A. Perley (UC Berkeley) report:
We began observations of GRB080319b with PAIRITEL at 2008-03-19
06:14:51 UT and will continue for several hours until sunrise. The
source is exceedingly bright in the first few minutes, visible on
individual 7.8 sec exposures in JHKs bands. Preliminary photometry,
which may be affected to non-linearities at these bright flux levels,
is given below.
# t (MJD) terr (day) filt mag merr
#####################################
54544.262141 0.000454 k 8.613900 0.033214 0 0
54544.261788 0.000454 j 9.110600 0.041347 0 0
A comparison with 2MASS may be found at:
http://lyra.berkeley.edu/~jbloom/grb080319b.png
This message may be cited.
- GCN Circular #7435
Y. Urata, M. Im, I. Lee, K.Y Huang, W.K. Zheng, L.P. Xin
on behalf of EAFON report:
"We have been monitoring the GRB 080319B optical afterglow (Racusin et
al. GCN 7427) using Mt. Lemmon 1m telescope with B, V, R, I and z'
band filter. The brightness at about 80 min after the burst is R~16.0
mag. derived from USNO-B1.0 catalog. Comparing with the further reports
by Li et al (GCN 7430), and Milen & Williams (GCN 7432), the light
curve shows shallower decay from around 0.05 days after the burst.
Further analysis and observations are in progress."
- GCN Circular #7437
R. J. Foley, D. Perley, and J. S. Bloom (UCB) on behalf of the GRAASP
collaboration report:
We obtained 2x1800 sec exposures of the optical afterglow (GCN 7428, 7430)
of GRB 080319B (GCN 7427) using GMOS on the Gemini-South telescope with
the R831 grating. The observations started at 20080319.35 (~2 hours after
the initial Swift trigger). Initial reductions show a featureless
continuum with no strong absorption systems, emission lines, or breaks.
Given our wavelength range of 595 - 815 nm, we can place the following
constraints on the redshift (in order of descending confidence):
(1) The lack of a Lyman limit implies z < 5.5.
(2) The lack of damped Lya or obvious Lya forest implies z < 3.9.
(3) The lack of obvious Mg II absorption implies z < 1.1.
Further analysis is in progress.
- GCN Circular #7438
W. Li, R. Chornock, D. A. Perley, and A. V. Filippenko, University of
California at Berkeley, on behalf of the KAIT GRB team:
We have analyzed the KAIT data on GRB 080319B (GCN 7472, 7428) as reported
in GCN 7430. Preliminary reduction of the unfiltered data, calibrated to
SDSS observations of the field, shows a smooth light curve from t = 20 to
120 minutes after the BAT trigger, with an apparent change in power-law
decay index at t ~ 35 minutes. The power-law decay index is measured to be
-1.89 +/- 0.04 between t = 20.1 to 26.3 minutes after the BAT trigger, and
-1.23 +/- 0.02 between t=60.9 to 117.2 minutes after the BAT trigger.
The shallower decay is also observed at t ~ 80 minutes as noted in GCN 7435.
We note this change in power-law decay index is reminiscent of what has
been observed in GRB 990123 (e.g. Akerlof et al. 1999, Nature 398, 400) and
GRB 021211 (e.g. Li et al. 2003, ApJ 586, L9), and suggests a transition from
reverse shock to forward shock emission.
Selected KAIT unfiltered photometry, all unfiltered data calibrated to
the R band via the SDSS calibration:
t(start; seconds after BAT trigger) exp mag merr
1207 20.0 14.110 0.008
1394 20.0 14.417 0.011
1576 20.0 14.645 0.011
1991 20.0 15.063 0.011
2912 20.0 15.710 0.014
3770 20.0 16.053 0.015
4380 20.0 16.247 0.014
5005 20.0 16.415 0.019
6820 20.0 16.843 0.017
- GCN Circular #7439
M.Cwiok, W.Dominik, G.Kasprowicz, A.Majcher, A.Majczyna,
K.Malek, L.Mankiewicz, M.Molak, K.Nawrocki, L.W.Piotrowski,
D.Rybka, M.Sokolowski, J.Uzycki, G.Wrochna, A.F.Zarnecki
on behalf of "Pi of the Sky" collaboration
http://grb.fuw.edu.pl
"Pi of the Sky" apparatus located at Las Campanas Observatory
imaged the region of GRB 080319b (Swift triger 306757 at 06:12:49 UT)
before, during and after the GRB with 10s exposures (IR-cut filter only).
We observe optical emission at the position given by Swift XRT.
start - end comment
6:12:33 - 6:12:43 not visible (>12 mag)
6:12:47 - 6:12:57 visible (~10 mag)
6:13:01 - 6:13:11 max. brightness (~6 mag)
Full light curve fill be published later.
- GCN Circular #7444
P.M. Vreeswijk (DARK), A. Smette (ESO), D. Malesani, J.P.U. Fynbo, Bo
Milvang-Jensen (DARK), P. Jakobsson (U. Hertfordshire), A.O. Jaunsen
(U. Oslo) and C. Ledoux (ESO) report on behalf of a larger
collaboration:
We observed the optical afterglow of GRB 080319B (Racusin et al., GCN
7427) with the Ultraviolet and Visual Echelle Spectrograph (UVES)
mounted at ESO's VLT Kueyen. Observations were performed in
rapid-response mode starting on 2008 March 19 at 07:18 UT.
The highest redshift system that we identify based on the MgII doublet
and various other features has z=0.937, the presumed redshift of GRB
080319B. Another system is identified at z=0.530.
We acknowledge excellent support from the observing staff at Paranal,
in particular Swetlana Hubrig and Elena Mason.
- GCN Circular #7445
M.Cwiok, W.Dominik, G.Kasprowicz, A.Majcher, A.Majczyna,
K.Malek, L.Mankiewicz, M.Molak, K.Nawrocki, L.W.Piotrowski,
D.Rybka, M.Sokolowski, J.Uzycki, G.Wrochna, A.F.Zarnecki
on behalf of "Pi of the Sky" collaboration
http://grb.fuw.edu.pl
Following GCN 7439 we give the preliminary light curve of GRB 080319b
(IR-cut filter only):
start - end frame magnitudo
6:12:33 - 6:12:43 <=96 limit >11.48
6:12:47 - 6:12:57 97 9.83
6:13:01 - 6:13:11 98 5.76
6:13:16 - 6:13:26 99 6.00
6:14:03 - 6:14:13 100 8.26
6:14:17 - 6:14:27 101 8.77
6:14:32 - 6:14:42 102 9.10
6:14:46 - 6:14:56 103 10.27
6:15:27 - 6:14:37 104 10.50
6:15:41 - 6:14:51 105 11.10
6:15:56 - 6:16:06 106 11.21
6:16:40 - 6:16:50 107 11.79
6:16:54 - 6:17:04 108 11.95
More information will be published at http://grb.fuw.edu.pl
- GCN Circular #7446
S. Covino, P. D'Avanzo, D. Fugazza, L.A. Antonelli, L. Calzoletti,
S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini, V. D'Elia, F.
D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C. Guidorzi, G.L.
Israel, E. Maiorano, N. Masetti, A. Melandri, E. Meurs, L. Nicastro,
E. Palazzi, E. Pian, S. Piranomonte, L. Stella, G. Stratta, G.
Tagliaferri, G. Tosti, V.Testa, S.D. Vergani, F. Vitali report on
behalf of the REM team:
We started a refined analysis of the REM observations of GRB 080319B
(GCN 7427, Racusin et al.). As already reported by Cwiok et al. (GCN
7439 and 7445) the optical counterpart of this GRB was exceptionally
bright at early time. We measured, about 1 min after the burst, R~6.4
assuming R=11.20 for the USNO star at coordinates RA,DEC =
14:31:23.61, 36:21:56.5. The source was already almost 2 mag fainter
half a minute later. In the H band the source was H~5 around the same
epoch.
Further analyses are in progress.
- GCN Circular #7449
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1859 s of overlapping XRT Photon Counting mode and UVOT
data for GRB 080319B, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 217.92113, +36.30269 which is equivalent
to:
RA (J2000): 14h 31m 41.07s
Dec (J2000): +36d 18' 09.7"
with an uncertainty of 1.4 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position
can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is
described by Goad et al. (2007, A&A, 476, 1401
http://www.swift.ac.uk/xrt_positions/Goad.pdf).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
- GCN Circular #7450
V. Beckmann (ISDC), S. Mereghetti (INAF/IASF-Milano), A. von Kienlin
(MPE), M. Beck, V. Savchenko (ISDC), J. Borkowski (CAMK/Torun), D. Gotz
(CEA/Saclay) report on behalf of the INTEGRAL SPI-ACS GRB team:
The three GRB reported on 2008-03-19 by the Swift team (GCN 7426, 7427,
7442) have been independently detected by the SPI Anti-Coincidence
System (ACS) on-board INTEGRAL.
Burst T0 duration max counts in 50 msec
------------------------------------------------------
GRB080319A 05:45:41 10s 370
GRB080319B 06:12:47 57s 5500
GRB080319C 12:25:55 25s 1200
The SPI-ACS light curves are available (both as images and data files)
at http://isdc.unige.ch/Soft/ibas/ibas_acs_web.cgi
The light curves, binned at 50 ms, are derived from 91 independent
detectors with different lower energy thresholds (mainly between 50 keV
and 150 keV) and an upper threshold at about 100 MeV. The ACS response
varies as a function of the GRB incident angle. For these reasons we
caution that the count rates cannot be easily translated into physical
flux units.
- GCN Circular #7451
P.M. Vreeswijk, Bo Milvang-Jensen (DARK), A. Smette (ESO),
D. Malesani, J.P.U. Fynbo (DARK), P. Jakobsson (U. Hertfordshire),
A.O. Jaunsen (U. Oslo) and C. Ledoux (ESO) report on behalf of a
larger collaboration:
Besides the absorption systems at z=0.937 and z=0.530 reported in GCN
7444, we also note the presence of two other systems at z=0.715 and
z=0.760 along the sightline toward GRB 080319B. The rest-frame
equivalent width of MgII 2796 for both the z=0.937 and z=0.715 systems
is large: greater than 1A. Finally, we detect several transitions
from FeII fine-structure levels from the z=0.937 system. Assuming that
the GRB afterglow is responsible for the FeII excitation (see
Prochaska et al. 2006, ApJ, 648, 95; Vreeswijk et al. 2007, A&A, 468,
83), this confirms the z=0.937 system to be the host of GRB 080319B.
- GCN Circular #7452
S. Karpov, G. Beskin, S. Bondar, C. Bartolini, G. Greco, A. Guarnieri,
D. Nanni, A. Piccioni, F. Terra, E. Molinari, G. Chincarini, F.M. Zerbi,
S. Covino, V. Testa, G. Tosti, F. Vitali, L.A. Antonelli, P. Conconi, G.
Cutispoto, G. Malaspina, L. Nicastro, E. Palazzi, E. Meurs, P. Goldoni
TORTORA wide-field optical camera (12 cm diameter, 20x25 deg FOV, TV-CCD,
unfiltered) mounted on REM robotic 60-cm telescope located at La Silla
(Chile) observed the field of GRB 080319B (GCN 7427, Racusin et al.)
before, during and after the gamma-emission with 0.13 s time resolution.
We observe optical emission at the position given by Swift XRT:
1. We did not detect any transient brighter than 8.5m (unfiltered,
near B) at T-100 - T+16 s
2. We detect rapidly rising OT (~5 second rise front) and observe it
between T+16 and T+30, the peak brightness has been around 5 m
3. Between T+30 and T+36 the observations have been paused due to
repointing of REM telescope
4. Since T+36 we continuously observe the transient until it faded below
the detection limit (~8.5m) at T+90 s
The detailed analysis is in progress.
This message may be cited.
- GCN Circular #7456
A. Cucchiara & D. B. Fox (PSU) report on behalf of a larger
collaboration:
"Starting on 2008 March 18.49 UT we used the Marcario LRS spectrograph
on the Hobby-Eberly Telescope (R ~ 230 ) to obtain one 1200s spectra
of the optical afterglow (Holland et al., GCN 7428) of GRB 080319B
(Racusin et al., GCN 7427). The spectrum covers the wavelength range
4100 to 10,500 Angstrom. We observe multiple metal absorption
features including the MgII doublet (2796, 2803 A) and MgI (2852 A) at
z ~ 0.937. We also detect lines at z ~ 0.760 (MnII 2576, MnII 2594 and
CaI 4227), z ~ 0.715 (MgII doublet) and z ~ 0.530 (NaI 5890,5896).
Our observations are consistent with the redshift and features
reported by Vreeswijk et al. (GCN 7444, 7451)."
- GCN Circular #7459
J. Racusin (PSU), D. N. Burrows (PSU), P. A. Evans (U Leicester), C.
Pagani (PSU), report on behalf of the Swift-XRT Team:
We have analysed the first four orbits of Swift-XRT data obtained for GRB
080319B (Racusin et al. GCN Circ. 7427), totaling 1.1 ks of Windowed
Timing (WT) data beginning 64 s after the BAT trigger, and 4 ks of Photon
Counting (PC) data beginning 5 ks after the BAT trigger.
The UVOT-enhanced XRT position has been given by Evans et al. in GCN Circ
7449.
The bright X-ray light-curve can be fit by a broken power-law, with an
initial decay index of 1.46 +/- 0.01 followed, after a break at 6100 +/-
440 seconds, by a steeper decay index of 2.48 +/- 0.10.
Both the WT and PC spectra are strongly affected by photon pile-up, which
can alter the spectral fits. To eliminate these effects, we exclude the
central 8 pixel radius region of the WT data, and the central 3 pixel
radius region of the PC data when creating the spectra. Preliminary fits
to the WT spectrum (64-4943 seconds), modeled with an absorbed power-law,
result in a photon index of 1.65 +/- 0.02 and an absorbing column at
z=0.937 (Vreeswijk et al., GCN Circ. 7444) of NH = (5.28 +/- 1.03)e20
cm^-2, in addition to Galactic absorption of 1.12e20 cm^-2 in the
direction of the burst, with a reduced Chi^2=1.05. The PC spectrum (5-19
ks) can be modeled as an absorbed power-law, with photon index of 1.92 +/-
0.07 and an absorbing column at z=0.937 of NH = (23.5 +/- 5.6)e20 cm^-2,
in addition to the Galactic absorption, with a reduced Chi^2=1.06. If we
freeze the NH in the PC model to the WT fitted value, we fit a photon
index of 1.73 +/ 0.04, with a reduced Chi^2=1.4, which excludes this model
as a viable fit. As another attempt to model the spectra without NH
evolution, we freeze the WT NH to the value from the PC spectral fits and
add an additional low energy thermal component. The resulting fits yield
a photon index of 1.73 +/- 0.02, kT=0.06 +/- 0.01 keV, and a reduced
Chi^2=1.07. Therefore, the extra thermal component is a possible
explanation for the apparent spectral evolution.
Assuming the source continues to decay with the same decay index of 2.5,
we predict an XRT count rate of 8.8e-4 counts/s at T+24 hours, which
corresponds to an 0.3-10.0 keV observed (unabsorbed) flux of 6.1e-14
(6.2e-14) ergs cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.
- GCN Circular #7461
M. Schubel, D. Reichart, M. Nysewander, A. LaCluyze, K. Ivarsen, J. A.
Crain, A. Foster, T. Brennan, J. Haislip, J. Styblova, and A. Trotter report:
Skynet observed the localization of GRB 080319B (Racusin et al., GCN 7427)
with three of the 16" PROMPT telescopes at CTIO beginning 32 seconds after
the trigger (15 seconds after notification) in UVRI.
We detect the afterglow (Racusin et al., GCN 7428) in all filters. At 92
seconds after the burst we measure V ~ 8.6 mag (calibrated to 3 NOMAD
stars), and at 147 seconds we measure I ~ 8.9 mag (calibrated to 6 USNO B1
stars).
- GCN Circular #7462
J. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), E. Fenimore (LANL),
N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
J. L. Racusin (PSU), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-120 to T+182 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 080319B (trigger #306757)
(Racusin, et al., GCN Circ. 7427). The BAT ground-calculated position is
RA, Dec = 217.919, 36.300 deg which is
RA(J2000) = 14h 31m 40.7s
Dec(J2000) = +36d 17' 58.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
The mask-weighted light curve shows a large long bump of a peak
starting at ~T-10 sec, ramping up until ~T+10 sec, then mostly a flat top
with some small structure superposed, then starting to decay at ~T+50 sec.
It returns nearly to background by ~T+64 sec at which point there is
a loss of data due to an on-board data product buffer overflow.
The data resumes at T+120 sec. There is still detectable emission
in the BAT 15-350 keV band out to T+180 sec (the limit of the data
downlinked so far). From other count rate data products, we can say
that there is no other peaks during the 60-sec missing event data window
and that the low-level emission is about 10-15% of the peak emission.
Given the missing data, T90 (15-350 keV) has to be >50 sec
(estimated error including systematics).
The time-averaged spectrum from T-3.8 to T+62.2 and T+120 to T+151 sec
is fit by a simple power-law model. The power law index
of the time-averaged spectrum is 1.04 +- 0.02. The fluence
in the 15-150 keV band is 8.1 +- 0.1 x 10^-05 erg/cm2.
The 1-sec peak photon flux measured from T+16.87 sec in the 15-150 keV band
is 24.8 +- 0.5 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/306757/BA/>
Due to a large backlog in downlinking the full data on this burst,
we currently do not have the usual data set out to long times yet.
Should the remaining data show that there is ongoing activity
for this burst past the data cutoff at T+182sec, then we will
issue an updated 'refined analysis' circular.
- GCN Circular #7464
P. Wozniak, W.T. Vestrand, J. Wren, and H. Davis
(Los Alamos National Laboratory)
The RAPTOR sky monitoring system began observing the location
of GRB 080319B more than an hour before the Swift BAT trigger
306757 (Racusin et al., GCN 7427). The first exposure with detectable
optical emission started ~2 seconds after the trigger at 06:12:50.9 UT.
A peak brightness of 5.6 mag was recorded in time interval from
06:13:21.2 to 06:13:31.2 UT, before the end of the gamma-ray emission.
Using the redshift z=0.937 from Vreeswijk et al. (GCN 7444) the
estimated luminosity of GRB 080319B exceeds that of GRB 990123.
Our response arrays RAPTOR-P and T began imaging at 06:14:24.3 UT
following the XRT localization trigger that interrupted the ongoing
follow-up measurements of GRB 080319A. The OT is detected by both
response instruments including all channels (V,R,I,clear) of the
simultaneous multicolor imager RAPTOR-T.
- GCN Circular #7465
Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona),
David W. Hogg (NYU), Michael R. Blanton (NYU), David J. Schlegel
(LBNL), J. Brinkmann (APO), Donald Q. Lamb (Chicago), Donald
P. Schneider (PSU), and Daniel E. Vanden Berk (PSU) report:
The Sloan Digital Sky Survey (SDSS) imaged the field of burst
GRB080319B prior to the burst. As these data should be useful
as a pre-burst comparison and for calibrating photometry,
we are supplying the images and photometry measurements for
this GRB field to the community.
Data from the SDSS, including 5 FITS images, 3 JPGS, and
3 files of photometry and astrometry, are being placed at
http://mizar.as.arizona.edu/~grb/public/GRB080319B
We supply FITS images in each of the 5 SDSS bands of a 8'x8'
region centered on the GRB position (ra=217.920 (14:31:40.7),
dec=36.3041 (36:18:14.8); GCN 7427), as well as 3 gri
color-composite JPGs (with different stretches). The units
in the FITS images are nanomaggies per pixel. A pixel is
0.396 arcsec on a side. A nanomaggie is a flux-density unit
equal to 10^-9 of a magnitude 0 source or, to the extent that
SDSS is an AB system, 3.631e-6 Jy. The FITS images have WCS
astrometric information.
In the file GRB080319B_sdss.calstar.dat, we report photometry
and astrometry of 193 bright stars (r<20.5) within 15' of the
burst location. The magnitudes presented in this file are asinh
magnitudes as are standard in the SDSS (Lupton 1999, AJ, 118,
1406). Beware that some of these stars are not well-detected
in the u-band; use the errors and object flags to monitor
data quality.
In the files GRB080319B_sdss.objects_flux.dat and
GRB080319B_sdss.objects_magnitudes.dat, we report photometry
of 705 objects detected within 6' of the GRB position.
We have removed saturated objects and objects with model
magnitudes fainter than 23.0 in the r-band. The fluxes listed
in GRB080319B_sdss.objects_flux.dat are in nanomaggies while
the magnitudes listed in GRB080319B_sdss.objects_magnitudes.dat
are asinh magnitudes.
All quantities reported are standard SDSS photometry, meaning
that they are very close to AB zeropoints and magnitudes are
quoted in asinh magnitudes. Photometric zeropoints are known
to about 2% rms. None of the photometry is corrected for
dust extinction. The Schlegel, Finkbeiner, and Davis (1998)
predictions for this region are A_U=0.059 mag, A_g=0.043 mag,
A_r = 0.031 mag, A_i=0.024 mag, and A_z=0.017 mag.
The file GRB080319B_sdss.spectro.dat contains a list of the
3 objects with SDSS spectroscopy within 6 arcminutes of the
GRB position. In addition to the redshift and 1-sigma error
for each object, this file also lists the object spectroscopic
classification.
SDSS astrometry is generally better than 0.1 arcsecond per
coordinate. Users requiring high precision astrometry should
take note that the SDSS astrometric system can differ from
other systems such as those used in other notices; we have
not checked the offsets in this region.
More detailed information pertaining to our SDSS GRB releases
can be found in our initial data release paper (Cool et
al. 2006, PASP 118, 733). See the SDSS DR4 documentation for
more details: http://www.sdss.org/dr5.
These data have been reduced using a slightly different
pipeline than that used for SDSS public data releases.
We cannot guarantee that the values here will exactly match
those in the data release in which these data are included.
In particular, we expect the photometric calibrations to differ
by of order 0.01 mag.
This note may be cited, but please also cite the SDSS data
release paper, Adelman-McCarthy et al. (2007, ApJS, 172, 634),
when using the data or referring to the technical documentation.
- GCN Circular #7469
Martin Jelinek, Alberto J. Castro-Tirado (IAA-CSIC Granada),
Virginie Chantry (Universit=E9 de Liege) and
Jorge Pl=E1 (IAC La Laguna), on behalf of a larger collaboration,
report:
"We are imaging the naked eye GRB 080319B detected by Swift
(GCN 7427) using.both the 1.2m Mercator Telescope at Obs. del
Roque de los Muchachos in La Palma, and the 0.8m IAC80 at
Obs. del Teide in Tenerife. Our R-band magnitude measured on
an image starting at 22:56UT (16.75 hr after the burst) is
about R=3D21.0. Further images are planned throughout the whole
night."
This message can be cited.
- GCN Circular #7470
H. Swan (U Mich), F. Yuan (U Mich), W. Rujopakarn (Steward)
ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
080319B (Swift trigger 306757; Racusin et al., GCN 7427) and began
imaging at 06:13:11.06 UT (5.3 sec after the GCN notice time) under
suboptimal conditions, because of condensation present on the CCD.
Observations continued until about 5 hours after the trigger. This
condensation made the analysis very difficult, but we detect the OT
first reported in GCN 7428. Further analysis is ongoing. These
unfiltered images are calibrated to the USNO B1.0 R2 catalog.
start UT end UT mag mlim(of image)
06:13:11.06 06:13:16.06 5.35 9.8
06:14:30.66 06:14:50.66 8.49 13.0
- GCN Circular #7471
Y. Urata, K.Y. Huang, C.Y. Shih, T.W. Chen, M. Im, I. Lee,
on behalf of EAFON report:
"We have monitored the GRB 080319B optical afterglow using Lulin 1-m
telescope with B, V, R, I and z' bands from 16:18 to 21:19 (UT).
Comparing with former observations made by the LOAO (Urata et al. GCN
7435), the R and I band light curves show an apparent temporal break
again at ~0.2 days after the burst. The decay index of the post-break
is ~-0.8."
This message may be cited.
- GCN Circular #7476
Martin Jelinek, Alberto J. Castro-Tirado (IAA-CSIC Granada),
Virginie Chantry (Universit=E9 de Liege) and
Jorge Pl=E1 (IAC La Laguna), on behalf of a larger collaboration,
report:
"We were imaging the naked eye GRB 080319B detected by Swift
(GCN 7427) using.both the 1.2m Mercator Telescope at Obs. del
Roque de los Muchachos in La Palma, and the 0.8m IAC80 at
Obs. del Teide in Tenerife.
Between two epochs of imaging, one started at 22:56 (~16.75hr
after the GRB), the other at 3:27UT (20h after) we measure an
aproximate decay index of ~1.3. Our R-band magnitude measured
on an image starting at 22:56UT (16.75 hr after the burst) was
about R=3D19.8. The value reported in the previous GCN 7469 has
been incorrect."
This message can be cited.
- GCN Circular #7481
A.J. van der Horst (NASA/ORAU) reports on behalf of a large collaboration:
"We observed the position of the GRB 080319B afterglow at 4.9 GHz with the
Westerbork Synthesis Radio Telescope at March 19 20.24 UT to March 20
8.22 UT, i.e. 14.0 - 26.0 hours after the burst (GCN 7427).
We do not detect a radio source at the position of the optical counterpart
(GCN 7428). The three-sigma rms noise in the map around that position is
84 microJy per beam. The formal flux measurement for a point source at the
position of the optical counterpart is 59 +/- 26 microJy.
We would like to thank the WSRT staff for rapidly scheduling and obtaining
these observations."
- GCN Circular #7482
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
and T. Cline on behalf of the Konus-Wind team report:
The bright GRB 080319B (Swift-BAT trigger #306757: Racusin et al., GCN
7427, Cummings et al., GCN 7462) triggered
Konus-Wind at T0=22370.339 s UT (06:12:50.339).
The burst light curve shows a single complex pulse
with a duration of ~60 s, followed by a long decaying tail
seen up to T-T0 ~200 s in the G1(18-70 keV) and G2(70-300 keV) bands
and even beyond in the G1 band.
Preliminary analysis of the Konus-Wind data
yields the burst fluence of 5.72(-0.13, +0.14)x10^-4 erg/cm2,
and a 64-ms peak flux measured from T0+19.2 s
of (2.17 +/- 0.21)x10^-5 erg/cm2/s
(both in the 20 keV - 7 MeV energy range).
The time-integrated spectrum of the main pulse
(from T0 to T0+59.648 s) can be fitted
(in the 25 keV - 7 MeV range)
by GRBM (Band) model for which:
the low-energy photon index is alpha = -0.822(-0.012, +0.014),
the high energy photon index beta = -3.87(-1.09, +0.44),
the peak energy Ep = 651 (-14, +13) keV (chi2 = 96.2/81 dof).
All the quoted errors are at the 90% confidence level.
Assuming z = 0.937 (Vreeswijk et al., GCN 7444, 7451) and a standard
cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.3, Omega_\Lambda =
0.7, the isotropic energy release is E_iso ~1.32x10^54 erg,
the maximum luminosity is (L_iso)_max ~9.67x10^52 erg/s, and
Ep_rest ~1261 keV.
The Konus-Wind light curve of this GRB is available
at http://www.ioffe.rssi.ru/LEA/GRBs/GRB080319_T22370/
- GCN Circular #7484
Veli-Pekka Hentunen (Varkaus, Finland), Arto Oksanen (Muurame, Finland),
and Petri Kehusmaa (Hyvinkaa, Finland) report to the AAVSO High Energy
Network the following optical detections and upper limits of GRB 080319B
(Racusin et al., GCN Circular #7427):
Veli-Pekka Hentunen and Markku Nissinen (Taurus Hill Obs., Varkaus,
Finland) report the detection of the optical afterglow of GRB 080319B
(Racusin et al., GCN Circular #7427). The afterglow was observed
unfiltered for a total of 1500 seconds using an SBIG ST8-XME CCD mounted
on a Meade LX200 0.3-m telescope. Observations commenced approximately
15.3 hours post-burst; the mid-point of the observations was 2008 March
19.8999 UT. The afterglow was clearly detected at an unfiltered
magnitude of 19.08 +/- 0.02, calibrated relative to USNO-A2.0
1200-07324239.
A detailed report of this observation is available at the following URL:
ftp://ftp.aavso.org/grb/Veli-PekkaHentunen_080319B_2454545.53358_.txt
A FITS image of this observation is available at the following URL:
ftp://ftp.aavso.org/grb/Veli-PekkaHentunen_080319B_2454545.53358_.fits
Petri Kehusmaa (Slope Rock Observatory, Hyvinkaa, Finland) reports a
non-detection of the optical afterglow of GRB 080319B. The afterglow
was observed through a V filter for a total of 1800 seconds using an
SBIG ST-7XME CCD mounted on a 0.2-m telescope. Observations commenced
approximately 17 hours post-burst; the mid-point of the observations was
2008 March 19.9675 UT. The afterglow was not detected in the V-band
with an upper limit of R=17.6 (calibrated relative to USNO-A2.0).
A detailed report of this observation is available at the following URL:
ftp://ftp.aavso.org/grb/PetriKehusmaa_GRB080319B_2454545.93778_.txt
A FITS image of this observation is available at the following URL:
ftp://ftp.aavso.org/grb/PetriKehusmaa_GRB080319B_2454545.93778_.fits
Arto Oksanen and Olli-Pekka Reimaala (Hankasalmi Obs., Hankasalmi,
Finland) also report the detection of the optical afterglow of GRB
080319B. The afterglow was observed unfiltered for a total of 2040
seconds (17 x 120s) using an SBIG STL-1001E CCD mounted on an RC Optical
Systems 0.4-m telescope. Observations commenced approximately 19.3 hours
post-burst; the mid-point of the observations was 2008 March 20.0639 UT.
The afterglow was clearly detected at an unfiltered (CR) magnitude 19.0
+/- 0.1, calibrated relative to USNO-A2.0. Note that this magnitude uses
a different comparison star from that of Hentunen and Nissinen (see
above), and may be offset by a few tenths of a magnitude.
A detailed report of this observation is available at the following URL:
ftp://ftp.aavso.org/grb/ArtoOksanen_GRB080319B_2454545.72325_.txt
A FITS image of this observation is available at the following URL:
ftp://ftp.aavso.org/grb/ArtoOksanen_GRB080319B_2454545.72325_.fits
The AAVSO thanks the Curry Foundation for their continued support of the
AAVSO International High Energy Network.
- GCN Circular #7485
Garrett Keating, Geoffrey Bower, Rick Forster, and J. S. Bloom (UC
Berkeley) report for the Allen Telescope Array team:
"The Allen Telescope Array observed GRB 080319B (Racusin et al.; GCN
7247) at a frequency of 1.43 GHz. Observations were obtained on 20
March 2008 between 5 and 7 UT. From this initial dataset, we report a
non-detection at the location of afterglow with a 3 sigma upper limit
of 18 mJy. Observations are continuing."
This message may be cited.
- GCN Circular #7486
D. A. Perley, J. S. Bloom (UC Berkeley) and H.-W. Chen (U Chicago) report:
On the night of 2008-03-20 (UT) we observed the optical afterglow of GRB
080319B (GCN 7427, Racusin et al.) with Gemini-South + GMOS in g, r, i,
and z filters (4x180s in each filter). The source is well-detected in
all bands. Magnitudes, calibrated to SDSS DR6, are:
UTstart UTend t(hr) filt mag err
06:52:17 07:10:19 24.808 g 20.95 0.09
07:11:19 07:26:11 25.099 r 20.55 0.03
07:27:10 07:42:04 25.363 i 20.40 0.05
07:43:04 07:57:55 25.686 z 20.32 0.03
We thank the observing staff for performing these observations.
- "Pi of the Sky" movie clip of the "naked eye burst"
http://grb.fuw.edu.pl/pi/ot/grb080319b/normal.html
- GCN Circular #7493
D. C.-J. Bock (CARMA), P. C. Chandra (NRAO/UVA), S. R. Kulkarni (Caltech),
D. A. Frail (NRAO), and S. B. Cenko (Caltech) report on behalf of a
larger collaboration:
We have observed the position of GRB080319B (Racusin et al.; GCN 7247)
with the Combined Array for Research in Millimeter-wave Astronomy (CARMA)
at 95 GHz on 2008 March 20 (mean time 11:30 UT). We report a non-detection
at the optical afterlow position with a 3-sigma limit of 0.75 mJy.
- GCN Circular #7496
S. T. Holland (CRESST/USRA/GSFC) & J. L. Racusin (PSU) report on
behalf of the Swift/UVOT team:
The Swift/UVOT observed the field of GRB 080319B starting 51 s
after the BAT trigger (Racusin et al., GCN Circ. 7427). We detect the
optical afterglow all filters. Preliminary magnitudes are reported
below.
Filter T_start (s) T_stop Exposure Mag Err Comment
v 175 575 393 <11.5 Saturated
b 654 664 10 13.39 0.01
u 630 649 19 12.44 0.01
uvw1 605 625 19 12.49 0.02
uvm2 581 600 19 13.39 0.05
uvw2 685 705 19 13.36 0.04
white 67 169 98 <13.9 Saturated
The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0 .01 mag (Schlegel et al.,
1998, ApJS, 500, 525). The photometry is on the UVOT flight system
described in Poole et al. (2008, MNRAS, 383,627).
- GCN Circular #7499
Nat Butler (UC Berkeley) reports:
I have applied our time-dependent pileup correction code (Butler &
Kocevski 2007; ApJ, 663, 407) to the XRT spectrum of GRB080319B (see, Racusin
et al., GCN 7459). Although I find similar temporal properties in the
afterglow decay to those quoted by the XRT team, I find significantly
different spectral properties. Notably, there is no significant evidence
for a time-variation in N_H and no significant need for a thermal component.
The WT model (0.4-10 keV) and PC mode (0.3-10 keV) spectra fitted jointly
and well (chi^2/nu=799.70/788) with an absorbed powerlaw yields:
Gamma = 1.84+/-0.01
N_H = 1.7+/-0.1 x 10^21 cm^(-2) @ z=0.937 (Vreeswijk et al., GCN 7451), in
addition to the expected Galaxy contribution along the line of sight. Here
we assume the solar chemical abundances from Anders & Ebihara (1982).
This value of N_H implies ~2 mag extinction in the observer frame V band
assuming the mean Galactic dust+gas properties.
Allowing the photon indices to vary separately: Gamma1=1.84^{+0.1}_{-0.2} and
Gamma2=1.85+/-0.05, closely consistent. The fractional possible increase in
rest-frame N_H between the WT mode data (t=660s to 4.95 ksec) and the PC mode
data (t=4.95 to 174 ksec) is modest and weakly significant:
0.74^{+0.43}_{-0.37}%. I suspect the indicated variations are purely due to
calibration uncertainties in the WT mode data. The hard WT mode spectral fit
in GCN 7459 can be reproduced by relaxing our pileup correction.
Additional evidence disfavors an interpretation of an evolving X-ray
spectrum:
Time resolved fits to the WT mode data show no significant evidence for
spectral evolution in the WT mode data considered alone. See,
http://astro.berkeley.edu/~nat/080319B_spec.jpg
The light curve is a simple (broken) powerlaw for the WT mode data, with
no flaring. Afterglows with such light curves typically exhibit weak
or no spectral evolution (e.g., Butler & Kocevski 2007, ApJ, 668, 400).
There is no significant variations in the X-ray hardness ratio for this event.
See, http://astro.berkeley.edu/~nat/080319B_hardness.jpg
A fit to BAT data (see also, Cummings et al., GCN 7462) in a time
region (58s to 303s; chi^2/nu=36.46/55) overlapping the XRT observation has
a roughly consistent powerlaw (Gamma=2.1+/-0.1), and also allows for a
smooth extrapolation in flux between BAT and XRT assuming a simple powerlaw
model connecting the flux in both instruments.
This message can be cited.
- GCN Circular #7501
G. Greco (Bologna University), F. Terra (Second University of
Roma "Tor Vergata"), C. Bartolini, A. Guarnieri, A. Piccioni
(Bologna University), F. Munz, G. Pizzichini (INAF/IASF Bologna),
D. Nanni (INAF/OAR and Second University of Rome "Tor Vergata"),
A. Shearer (Centre for Astronomy, Galway), R. Gualandi
(Bologna Observatory) report:
We observed the field of GRB 080319B (GCN 7427, Racusin et al.)
with the 152 cm telescope located in Loiano under unfavorable
conditions due to the illumination of the full moon.
By adding four consecutive 10 min exposures in the Rc filter at
mean time 2008 March 20.947 UT we do not detect any object at
the position of the optical bright afterglow reported by
Racusin et al. (GCN 7428).
Our 3-sigma limiting magnitude is R~20.3 (based on Nomad1 catalogue).
The image has been posted in our public directory
from where it can be retrieved
by sftp using
hostname: ermione.bo.astro.it
username: publicGRB
password: GRB_bo.
directory: GRB080319B
- GCN Circular #7502
S. Karpov, G. Beskin (SAO RAS, Russia), S. Bondar (RIPI, Russia), C. Bartolini,
G. Greco, A. Guarnieri, A. Piccioni (Astronomy Department of Bologna
University, Italy), D. Nanni, F. Terra (Second University of Roma "Tor
Vergata", Italy), E. Molinari, G. Chincarini, F.M. Zerbi, S. Covino, V. Testa
(Osservatorio Astronomico di Brera, Italy), G. Tosti (Universita di Perugia,
Italy), F. Vitali, L.A. Antonelli (Osservatorio Astronomico di Roma, Italy),
P. Conconi, G. Cutispoto (Osservatorio Astronomico di Catania, Italy),
G. Malaspina (Osservatorio Astronomico di Brera, Italy), L. Nicastro (Istituto
di Astrofisica Spaziale e Fisica Cosmica, Palermo, Italy), E. Palazzi (Istituto
di Astrofisica Spaziale e Fisica Cosmica, Bologna, Italy), E. Meurs (Dunsink
Observatory, Ireland), P. Goldoni (Observatori Astronomic - Universitat de
Valencia Edificio de Institutos de Investigacion, Spain)
report on behalf of TORTOREM team:
Following GCN 7452 we publish a preliminary light curve of GRB 080319b with
reduced temporal resolution (10 frames time binning, 1.3 seconds effective
exposure, no gaps between frames). The photometry is performed in instrumental
system and calibrated towards the V magnitudes of nearby Tycho2 stars. The
light curve is available online at
http://vo.astronet.ru/~karpov/grb080319b_lc_10.gif
The light curve shows fast (~5 seconds) uprise towards the peak V=5.5 at T+23,
complex multi-peak structure till T+50 and featureless decay then. In total,
the transient has been visible for ~65 seconds; 6 seconds in the T+30 - T+36
interval are currently excluded from the analysis due to repointing of REM
telescope at that time.
The light curve is consistent with the one published by Pi of the Sky (Cwiok et
al, GCN 7445).
The video sequence of the data is available at
http://vo.astronet.ru/~karpov/grb080319b.avi
and with reduced temporal resolution at
http://vo.astronet.ru/~karpov/grb080319b_lowres.avi
The results of analysis of full-resolution (0.13s exposure) data will be
published later.
- GCN Circular #7504
We observed GRB 080319B using 40cm Newtonian telescope, SBIG ST-7XMEi
CCD camera and R-band Kron-Cousins filter. We found afterglow to be
R=20.0+-0.3 mag at 2008.03.20 0.125 UT. Given time is mid-exposure
(total exposure: 6.7h). Weather conditions were poor because of clouds
and Moon. We used 13 nearby USNO-B1.0 stars to get R magnitude. An
aperture photometry package Munipack
(http://adsabs.harvard.edu/abs/1998stel.conf...30H) was used for data
reduction.
Rudolf Novak
Nicholas Copernicus Observatory & Planetarium in Brno, Czech Republic
(http://ccd.astronomy.cz)
Filip Hroch
Masaryk University, Brno
(http://monteboo.blogspot.com)
- GCN Circular #7506
Alicia Soderberg (Princeton), Poonam Chandra (U. Virginia), and Dale
Frail (NRAO) report on behalf of a larger collaboration:
"We observed the field of GRB 080319B (GCN 7427) with the Very
Large Array beginning at Mar 21.56 UT. At 4.86 GHz we detect a radio
source coincident with the optical afterglow position (GCN 7428) at
coordinates (J2000):
RA = 14 31 41.01 +/- 0.05
Dec = 36 18 09.7 +/- 0.4
with flux density 189 +- 39 microJy. Further observations are scheduled.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
- GCN Circular #7507
A.J. van der Horst (NASA/ORAU) reports on behalf of a large collaboration:
"We re-observed the position of the GRB 080319B afterglow at 4.9 GHz with
the Westerbork Synthesis Radio Telescope at March 21.84 to 22.03 UT and at
March 22.84 to 23.03 UT, i.e. 2.7 and 3.7 days after the burst (GCN 7427).
We do not detect a radio source at the position of the optical counterpart
(GCN 7428) at 2.7 days. The three-sigma rms noise in the map around that
position is 108 microJy per beam. We note that this upper limit is not
consistent with the almost simultaneous VLA detection at 4.86 GHz reported
in GCN 7506.
We tentatively detect a radio source at 4 sigma significance at 3.7 days,
with a flux density of 163 +/- 39 microJy.
We would like to thank the WSRT staff for scheduling and obtaining these
observations."
- GCN Circular #7509
H. Teplitz (IPAC), M. Werner (JPL), S. B. Cenko, S. R. Kulkarni and A. Rau
(Caltech) report on behalf of a larger collaboration:
We have imaged the field of GRB080319B (Racusin et al., GCN 7427) with the
blue filter (15.8 um) of the IRS peak-up camera on board the Spitzer Space
Telescope. Observations consisted of 60 pointings, each with two dithered
30 s cycles, beginning at March 21.81 UT (~ 2.55 d after the burst). At
the location of the optical afterglow, we measure a flux density of 35.7
+/- 3.9 uJy.
We wish to thank the entire Spitzer team for the prompt execution of these
observations.
- GCN Circular #7511
Bin-Bin Zhang (University of Nevada Las Vegas), Enwei Liang (Guangxi=20
University, China) and Bing Zhang (University of Nevada Las Vegas) report=
:
We have processed the Swift XRT data of GRB 080319B, paying special=20
attention to the possible spectral evolution in the WT mode data=20
(Racusin et al. GCN 7459; cf. Butler GCN 7499). We perform a=20
time-dependent spectral analysis using the method described in (Zhang,=20
Liang & Zhang 2007, ApJ, 666, 1002). Since the early data are strongly=20
affected by photon pile-up, we use a box annulus region for the WT mode=20
data (outer radius 40*20, inner radius 8*20; see also Racusin et al. GCN=20
7459) and time-dependent circle annulus regions for the PC mode data to=20
extract spectra and lightcurves. We fit the time-dependent spectra using=20
a simple power-law model with the absorption from the MilkyWay Galaxy=20
(NH_G=3D1.12e20 cm^{-2} ) and from the host galaxy (NH_host=3D7.3e20=20
cm^{-2}, obtained from fitting to the integrated 1st orbit WT mode=20
spectrum). We confirm Butler (GCN 7499) that the apparent spectral=20
evolution after 200 seconds is due to instrumental "pile up" effect.=20
However, in the very early time t ~ (68-100) seconds, an apparent weak=20
but significant hard-to-soft spectral evolution sustains even if we take=20
into account the pile-up corrections. The photon index evolves from 1.67=20
=C2=B1 0.02 to 1.77 =C2=B1 0.02 during this period. Our results can be fo=
und at=20
http://grb.physics.unlv.edu/~xrt/xrtweb/080319B/080319B.html.
To make sure that this early-time spectral evolution is not due to the=20
pile-up effect, we extract the time-dependent spectra with box annuli=20
having different sizes. By excluding the central regions, we enlarge the=20
outer radius up to 80 pixel * 20 pixel to make sure that there are=20
enough photons for the spectral analysis. Our tests show that even if=20
the inner box size is as large as 30 pixel * 20 pixel (spectra in annuli=20
with such a large inner radius is not possible to be affected by the=20
pile-up effect), the early time (before 200 seconds) XRT WT data still=20
show significant spectral evolution. We therefore cautiously conclude=20
that this early spectral evolution is likely intrinsic.
Strong hard-to-soft spectral evolution has been seen in the early steep=20
decay phase of many GRB X-ray afterglows (e.g. Zhang et al. 2007, 666,=20
1002), which points towards a non-forward-shock origin of the emission.=20
We notice that the lightcurve before 200 seconds show several weak=20
flaring/flicking features, which is more easily seen in linear scale=20
(see http://grb.physics.unlv.edu/~xrt/xrtweb/080319B/earlylc.png). In
view that some steep decay segments with overlapping flares typically=20
show hard-to-soft spectral evolution (Group C in Zhang et al. 2007), we=20
suspect that the weak spectral evolution in this burst is also related=20
to the weak flaring/flicking features. It is however puzzling why this=20
segment naturally transforms to a smooth decay after 200 seconds which=20
show no further spectral evolution.
Throughout our fit we have fixed the NH_host values. Another possibitly=20
is that the apparent spectral evolution is caused by a varying NH_host=20
value (Racusin et al. GCN 7459). We test such a scenario by fixing the=20
photon index to \Gamma=3D1.76 (average value after 200s) and fit the=20
time-dependent spectra before 200s using the same model=20
(wabs*zbwas*zwabs) but allowing NH_host to be a free parameter. We=20
obtain acceptable fits, and found that the NH_host in the early time=20
evolves dramatically to one half of its initiall valve (from ~ 1.1e21=20
cm^{-2} to ~ 6.6e20 cm^{-2}). The time evolution of the NH_host value=20
can be found at http://grb.physics.unlv.edu/~xrt/xrtweb/080319B/nh.png.
This is another plausible physical scenario, although a model for the
rapid depletion of NH_host is called for.
The reduced chi2 in our fitting to the wabs*zwabs*powerlaw model is=20
typically ~1. Although a possible thermal component has been suggested=20
(cf. Racusin et al. GCN 7459), in our fitting no thermal component is=20
required by the data.
This message can be cited.
- GCN Circular #7519
Yu. Krugly, I. Slyusarev (Institute of Astronomy of Kharkiv National
University), A. Pozanenko (IKI) report on behalf of larger collaboration:
We observed the afterglow of GRB080319B (Racusin et al. GCN 7427) with 0.7m
telescope of Institute of Astronomy, Kharkiv National Univ. starting on (UT)
March 19, 18:20 and continuing to March 20, 02:44. The series consist of
continuous observations in R and a few frames were taken in V around (UT)
19:58.
The afterglow (Racusin et al. GCN 7427, Holland et al. GCN 7428, Li et al.
GCN 7430) is detected in the obtained single images.
Preliminary photometry of combined images reveals a possible rapid decline
of the light curve between (UT, mid time) 18:25 (R~19.1) and 19:04 (R~19.9)
and then light curve flattering toward the end of observation March 20 (UT)
02:00 (R~20.1). The light curve between (UT) 19:00 and 02:39 is close to a
constant and not compatible with power law decay index of alpha=1.2.
The magnitude of the comparison star is based on SDSS calibration (Cool et
al, GCN 7465).
The message may be cited.
- GCN Circular #7528
A. Henden (AAVSO) reports:
While the field of GRB080319B has been observed by SDSS, we have also
obtained a four-night BVRcIc field calibration using the 35cm robotic
telescope at Sonoita Research Observatory. The calibration file
has a limiting magnitude around V=16, with good standards brighter
than V=11 or so. The file is available at
ftp://ftp.aavso.org/public/calib/grb/grb080319b.dat
This calibration is based on numerous Landolt standards, and has
an external zeropoint error of about 0.02mag. We are continuing
calibration of this field, moving to the west to pick up the
9th magnitude star SAO 64192, and will extend the calibration
file when that photometry is available. Our system is available
for any other bright BVRI calibrations (4
The AAVSO thanks the Curry Foundation for their continued support of the
AAVSO International High Energy Network.
- GCN Circular #7535
D. A. Perley, J. S. Bloom (UC Berkeley) and H.-W. Chen (U Chicago) report:
We have continued to monitor the optical afterglow of GRB 080319B from
Gemini-South. Additional images were taken on UT March 21, 25, and 28.
Despite the presence of the Moon and low elevation of the target, the
afterglow remains detected in all filters. We report on photometry,
calibrated to SDSS DR6, as follows (including an improved analysis of
images obtained on UT March 20, previously reported in GCN 7486).
t(hr) filt mag err
24.808 g 20.83 0.05
25.099 r 20.53 0.02
25.363 i 20.37 0.03
25.686 z 20.32 0.04
48.653 r 21.56 0.03
144.553 g 23.59 0.15
144.886 r 23.49 0.09
145.220 i 23.13 0.06
145.553 z 23.48 0.11
216.703 r 23.56 0.06
217.036 i 23.28 0.06
The object appears visibly extended at late times, with a possible
projection extending to the south; this may be the host galaxy of this
gamma-ray burst. The imaging was acquired under variable seeing
conditions and we caution that the presence of an underlying host may
complicate the photometry.
While roughly consistent with simple power-law decay of alpha=1.2-1.3
(e.g. GCN 7438, Li et al.), in detail the observations deviate slightly
from a simple power-law, including a flattening in the last two sets of
observations that may be due host galaxy light (and possibly a small
amount of supernova contribution.)
In addition, we note the presence of a very red source at an offset of
2.65" (slightly west of south) from the afterglow. Preliminary
photometry of this object gives the following:
g = 24.3 +/- 0.2 (marginal detection)
r = 23.76 +/- 0.06
i = 22.55 +/- 0.03
z = 21.71 +/- 0.03
This offset corresponds to 21 kpc at a redshift of 0.937 (Vreeswijk et
al., GCN 7451). It is dominated by a bright PSF-like center but also is
visibly extended to the south. It may be an intervening absorber.
Further follow-up is planned and encouraged.
- 0803.3215from 24 Mar 2008
Bloom: Observations of the Naked-Eye GRB 080319B: Implications of Nature's Brightest Explosion
Abstract: The first gamma-ray burst (GRB) confirmed to be bright enough to be seen with
the naked eye, GRB 080319B, allowed for exquisite follow-up across the
electromagnetic spectrum. We present our detailed optical and infrared
observations of the afterglow, consisting of over 5000 images starting 122 s
after the GRB trigger, in concert with our own analysis of the Swift UVOT, BAT,
and XRT data. The event is extreme not only in observed properties but
intrinsically: it was the most luminous ever recorded at optical wavelengths
and had an exceedingly high isotropic-equivalent energy release in gamma-rays.
At early times, the afterglow evolution is broadly consistent with being
reverse-shock dominated, then is subsumed by a forward shock at around 1000 s.
Analysis of the forward shock suggests that the remarkable energetics of this
burst may be owed largely to extreme collimation. The spectral energy
distribution, spanning from ultraviolet through near-infrared, shows no
evidence for a significant amount of dust extinction in the host frame. We do
find significant color evolution in the optical afterglow: starting at about
1000 s the index shifts blueward before apparently shifting back to the red at
late times. Finally, we examine the detectability of such events with current
and future facilities and find that such an event could be detected in
gamma-rays by BAT out to z = 4.9 (8 sigma), while the nominal EXIST sensitivity
would allow detection to z = 12.2. At K-band this source would have been easily
detected with meter-class telescopes to z = 17.
- GCN Circular #7558
S. Karpov, G. Beskin (SAO RAS, Russia), S. Bondar (RIPI, Russia), C. Bartolini,
G. Greco, A. Guarnieri, A. Piccioni (Astronomy Department of Bologna
University, Italy), D. Nanni, F. Terra (Second University of Roma "Tor
Vergata", Italy), E. Molinari, G. Chincarini, F.M. Zerbi, S. Covino, V. Testa
(Osservatorio Astronomico di Brera, Italy), G. Tosti (Universita di Perugia,
Italy), F. Vitali, L.A. Antonelli (Osservatorio Astronomico di Roma, Italy),
P. Conconi, G. Cutispoto (Osservatorio Astronomico di Catania, Italy),
G. Malaspina (Osservatorio Astronomico di Brera, Italy), L. Nicastro (Istituto
di Astrofisica Spaziale e Fisica Cosmica, Palermo, Italy), E. Palazzi (Istituto
di Astrofisica Spaziale e Fisica Cosmica, Bologna, Italy), E. Meurs (Dunsink
Observatory, Ireland), P. Goldoni (APC, SAp/CEA, Paris)
report on behalf of TORTOREM team:
We performed additional analysis of Tortora data on early optical
transient of GRB 080319B (GCN 7427, Racusin et al.) reported by us in
GCN 7502 and found the systematic error of 6.1 s in the time zero
point. To compensate it, all data points have to be shifted 6.1 s to
earlier times. The modified light curve, also including minor
photometric adjustments, is available at
http://vo.astronet.ru/~karpov/grb080319b_lc_10_shifted.gif
We apologize for any inconvenience this may have caused.
- 0804.0621 from 4 Apr 2008
Dado: Is there anything special about GRB 080319B?
Abstract: We show that the properties of gamma ray burst 080319B and its afterglow are
well reproduced by the cannonball model of long gamma ray bursts (GRBs). It was
an ordinary GRB, produced by a jet of highly relativistic plasmoids (CBs),
ejected in a core-collapse supernova (SN) and viewed, as some others before,
particularly close to the CB-emission axis. It still remains to be seen whether
GRB 080319B was associated with an SN akin to SN1998bw, the SN type ordinarily
associated with GRBs, or with a much more luminous SN.
- GCN Circular #7567
J.L. Racusin (PSU), S.R. Oates (UCL-MSSL), P. Schady (UCL-MSSL), S. T.
Holland (CRESST/USRA/GSFC), D.N. Burrows (PSU), report on behalf of the
Swift XRT and UVOT teams:
We have analyzed the first 19 days of Swift XRT data from GRB 080319B
(Racusin et al. GCN 7427), with a total exposure time of 200 ks. The
light curve can be fit by a triple broken power-law with initial decay
slope of 1.54+/-0.01, breaking at 2790+/-664 s to a slope of 1.85+/-0.05,
breaking again at 41.4+/-9.0 ks to a slope of 1.17+/-0.06, and finally
breaking at 1.04+/-0.43 Ms to a slope of 2.9+/-2.3.
If this last break is interpreted as a jet break, the jet opening
half-angle is 8 degrees x (n/10 cm^-3)^(1/8). We obtained Eiso=1.3x10^54
ergs (25 kev - 7 MeV) from Golenetskii et al. (GCN 7482), assuming
cosmological parameters of H_0=70 km/s/Mpc, Omega_M=0.3, Omega_Lambda =
0.7. The corresponding beaming corrected energy is 1.3 x 10^52 ergs.
The uncertanties in the post-jet break slope and time are large.
Therefore, the evidence for a break is preliminary and further
observations will be required to confirm it.
Late-time UVOT white filter observations are also suggestive of a break at
approximately the same time as the X-ray break. However, further
observations are needed to confirm the break because the afterglow flux is
near the UVOT detection limit.
We strongly encourage additional late-time optical follow-up to further
test for achromaticity and constrain the possible jet break.
This circular is an official product of the Swift Team.
- GCN Circular #7569
N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick),
A. S. Fruchter, J. Graham (STScI), K. Wiersema, E. Rol (U. Leicester)
report on behalf of a larger collaboration:
We obtained observations of GRB 080319B (GCN 7427) with HST/WFPC2 in
F606W and F814W filters on 2008 April 7th (2 orbits in each filter).
These data show the fading afterglow at magnitude F(814W_AB)=24.2
and F(606W_AB)=24.5. This fading is consistent within
the errors with a continued power-law decline in optical
brightness.
PSF subtraction reveals no obvious sign of an underlying host galaxy,
although there is what appears to be a separate galaxy 1.5 arcsec to
the south, which might be producing one of the foreground absorption
systems (GCN 7451).
A colour image showing the field around the GRB is available at:
http://www.star.le.ac.uk/~nrt3/080319b.html
Further analysis is ongoing.
- GCN Circular #7621
N. R. Tanvir (U. Leicester), D. A. Perley (UC Berkeley),
A. J. Levan (U. Warwick), J. S. Bloom (UC Berkeley),
A. S. Fruchter (STScI) and E. Rol (U. Leicester) report:
We obtained a further epoch of observations of GRB 080319B with
Gemini-North/GMOS on April 14 UT. These observations yielded the
following magnitudes: g=25.80+/-0.09, r=24.93+/-0.07, i=24.22+/-0.05.
Although the r-band magnitude is consistent with a continued power-law
decline in flux, the source is now clearly much redder than it was at
early times, suggesting it is likely contaminated by light from a host
galaxy and/or associated supernova. The g-band observation, which
would be less contaminated by any SN light, indicates a steeper
decline which may be consistent with a break in the underlying
afterglow light curve (GCN 7567).
The absence of any extended emission in the previous HST observations
(GCN 7569) argues against a significant host contribution, although a very
compact host is not ruled out.
Further analysis is ongoing.
We thank Gemini staff astronomers, particularly Sandy Leggett, for
their support in obtaining these observations.
- GCN Circular #7627
D. A. Kann, S. Schulze (TLS Tautenburg) & A. C. Updike (Clemson
University) report:
In light of recent reports on the further evolution of GRB 080319B, we did
a preliminary analysis of the multiwavelength data set.
Jet Break:
Racusin et al. (GCN 7567) reported the existence of a potential jet break
at 1.04 +/- 0.43 Ms in the X-ray band, with a hint of a steeper decay seen
in the optical as well. Using the most up-to-date data from the Swift XRT
light curve repository (Evans et al. 2007), we confirm the findings of
the Swift team and derive (using data starting at 0.5 days after the GRB):
chi^2/d.o.f. = 39/58
alpha_1 = 1.01 +/- 0.05
alpha_2 = 2.40 +/- 0.39
t_b = 9.43 +/- 1.73 days (0.815 +/- 0.149 Ms)
n = 5 fixed, no "host galaxy"
These values are in agreement with those of the Swift team, with
significantly reduced errors. We note that there seems to be a steep decay
in the X-ray light curve from 0.35 to 0.5 days, and a similar evolution
has been reported in the optical (Krugly et al., GCN 7519) at about the
same time. This is reminiscent of the X-ray light curve of GRB 070110
(Troja et al. 2007).
In the optical, we add data from Perley et al. (GCN 7535) and Tanvir et
al. (GCN 7621) to the data set from Bloom et al. 2008 (arXiv:0803.3215).
Tanvir et al. report a significant reddening, which we confirm.
At the moment, it is unclear how much the host galaxy and a potential
supernova contribute in the g band, but a roughly achromatic steepening is
seen in this band (Tanvir et al.) in comparison to the X-ray light curve.
Energetics:
Using the prompt emission data derived from Konus-Wind (Golenetskii et
al., GCN 7482), we find in the bolometric band (1 - 10000 keV, host
frame):
E_iso = 1.32 +/- 0.03 x 10^54 erg (log E_iso = 54.12)
In the sample of Kann et al. 2007 (arXiv:0712.2186), only two GRBs (000131
and 990123) exceed this value.
Using the jet break time derived above, as well as the redshift z=0.937
(Vreeswijk et al., GCN 7444), and assuming standard parameters
(constant-density medium, circumburst density n = 10 cm^-3, efficiency eta
= 0.2), we find:
theta_jet = 10.24 +/- 0.71 degrees
E_jet = 2.11 +/- 0.30 x 10^52 erg (log E_jet = 52.3)
This value is comparable to or higher than for GRB 050904 (Tagliaferri et
al. 2005, Frail et al. 2006), GRB 050820A (Cenko et al. 2006) and GRB
070125 (Updike et al. 2008, Chandra et al. 2008), implying that this is
the fourth hyper-energetic GRB (cf. Chandra et al. 2008). We note that
broadband modeling may refine the circumburst density; if it is
significantly higher than 10 cm^-3, the colimation-corrected energy
will also be significantly higher.
Supernova:
In the i' band, the afterglow does not show a late steep decay, indicating
the possibility of a supernova that is by now contributing to the optical
transient (Tanvir et al.). Using the composite light curve (Bloom et al.)
shifted to the i' band (using the early Rc - i' color), and assuming an
achromatic break (t_b, alpha_2 fixed from the X-ray fit) and no host
galaxy, we find, using data after 0.7 days (after the steep decay +
plateau phase, Krugly et al.):
chi^2/d.o.f. = 44/10 (scatter)
alpha_1 = 1.33 +/- 0.02
k = 2.40 +/- 0.15
s = 1 fixed (stretch factor)
k is the peak luminosity in units of the SN 1998bw peak luminosity. This
is a high value (Ferrero et al. 2006) and represents an upper limit on the
SN flux. Assuming m_host(i') = 25, we find k = 1.24 +/- 0.14, a more
reasonable result, indicating the contribution of a host galaxy to
the late afterglow.
This message may be cited.
- 0804.2141from 14 Apr 2008
DElia: The prompt, high resolution spectroscopic view of the "naked-eye" GRB080319B
Abstract: GRB080319B reached 5th optical magnitude during the burst. Thanks to the
VLT/UVES rapid response mode, we observed its afterglow just 8m:30s after the
GRB onset when the magnitude was R ~ 12. This allowed us to obtain the best
signal-to-noise, high resolution spectrum of a GRB afterglow ever (S/N per
resolution element ~ 50). The spectrum is rich of absorption features belonging
to the main system at z=0.937, divided in at least six components spanning a
total velocity range of 100 km/s. The VLT/UVES observations caught the
absorbing gas in a highly excited state, producing the strongest Fe II fine
structure lines ever observed in a GRB. A few hours later the optical depth of
these lines was reduced by a factor of 4-20, and the optical/UV flux by a
factor of ~ 60. This proves that the excitation of the observed fine structure
lines is due to ``pumping'' by the GRB UV photons. A comparison of the observed
ratio between the number of photons absorbed by the excited state and those in
the Fe II ground state suggests that the six absorbers are $\gs18-34$ kpc from
the GRB site, with component I ~ 2 times closer to the GRB site than components
III to VI. Component I is characterized also by the lack of Mg I absorption,
unlike all other components. This may be due to a higher gas temperature,
suggesting a structured ISM in this galaxy complex.
- 0805.0144from 1 May 2008
Kumar: What did we learn from gamma-ray burst 080319B ?
Abstract: The optical and gamma-ray observations of GRB 080319B allow us to determine a
fairly complete physical picture for this remarkable burst. The data indicate
that the prompt optical and gamma-ray photons were produced at the same
location but by different radiation processes: synchrotron and synchrotron
self-Compton, respectively. The burst emission was produced at a distance of
10^{16.5} cm from the center of explosion by an ultra-relativistic source
moving at Lorentz factor of ~500. A straightforward inference is that about 10
times more energy must have been radiated at tens of GeV than that released at
~1 MeV. Assuming that the GRB outflow was baryonic and that the gamma-ray
source was shock-heated plasma, the collimation-corrected kinetic energy of the
jet powering GRB 080319B was larger than 10^{52.3} erg. The decay of the early
afterglow optical emission (up to 1 ks) is too fast to be attributed to the
reverse shock crossing the GRB ejecta but is consistent with the expectations
for the "large-angle emission" released during the burst. The pure power-law
decay of the optical afterglow flux from 1 ks to 10 day is most naturally
identified with the (synchrotron) emission from the shock propagating into a
wind-like medium. However, the X-ray afterglow requires a departure from the
standard blast-wave model.
- GCN Circular #7710
A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), A.S. Fruchter (STScI)
and J. Graham (STScI) report:
We have obtained a second epoch of HST observations of GRB 080319B on 11
May 2008. 2 orbits (3200s) of observations were taken in the F606W and
F814W filters. The afterglow has clearly faded from our first epoch of
observations and a faint host galaxy is now visible at the afterglow
location. We measure magnitudes for the combined (afterglow+host) source
of;
F606W(AB)=26.3 +/ -0.1
F814W(AB)=25.9 +/ -0.1
Relative astrometry between the two epochs of HST observations suggests
that the afterglow is marginally (0.1 +/- 0.05 arcseconds) offset from the
centroid of the host galaxy in the F606W image. This implies that the
afterglow may not be the dominant source of light at the current epoch,
and is likely significantly fainter than the magnitudes quoted above.
- GCN Report 134.1
GCN_Report 134.1 has been posted:
http://gcn.gsfc.nasa.gov/reports/report_134_1.pdf
by J.L.
at Racusin
titled: "PSU"
- 0805.1557from 11 May 2008
Racusin: GRB 080319B: A Naked-Eye Stellar Blast from the Distant Universe
Abstract: Long duration gamma-ray bursts (GRBs) release copious amounts of energy
across the entire electromagnetic spectrum, and so provide a window into the
process of black hole formation from the collapse of a massive star. Over the
last forty years, our understanding of the GRB phenomenon has progressed
dramatically; nevertheless, fortuitous circumstances occasionally arise that
provide access to a regime not yet probed. GRB 080319B presented such an
opportunity, with extraordinarily bright prompt optical emission that peaked at
a visual magnitude of 5.3, making it briefly visible with the naked eye. It was
captured in exquisite detail by wide-field telescopes, imaging the burst
location from before the time of the explosion. The combination of these unique
optical data with simultaneous gamma-ray observations provides powerful
diagnostics of the detailed physics of this explosion within seconds of its
formation. Here we show that the prompt optical and gamma-ray emissions from
this event likely arise from different spectral components within the same
physical region located at a large distance from the source, implying an
extremely relativistic outflow. The chromatic behaviour of the broadband
afterglow is consistent with viewing the GRB down the very narrow inner core of
a two-component jet that is expanding into a wind-like environment consistent
with the massive star origin of long GRBs. These circumstances can explain the
extreme properties of this GRB.
- 0806.2010from 12 Jun 2008
Yu: GRB 080319B: optical and gamma-ray emissions from internal forward-reverse shocks
Abstract: The temporal coincidence between the prompt $\gamma$-ray and optical
emissions of gamma-ray burst (GRB) 080319B suggests that they may originate
from a same emitting region or two regions sharing the same dynamical behavior.
Meanwhile, the significant excess of the optical flux over the extrapolation of
the $\gamma$-ray spectrum to the optical band indicates two different emission
components. We here consider the popular internal shock model where a forward
and a reverse shock are generated simultaneously during a collision of two
relativistic shells. In the case that the Lorentz factors of these two shocks
are very different, the synchrotron emission driven by them could peak at two
different energy bands. We show that such a two-component synchrotron scenario
can account for the prompt optical and $\gamma$-ray emissions of GRB 080319B
under some unique conditions. In addition, the luminosity of an inverse-Compton
sub-GeV or GeV component predicted in this scenario is not higher than that of
synchrotron MeV gamma-rays, which could be tested by the {\em Gamma-ray Large
Area Space Telescope} (GLAST).
- 0809.0189from 1 Sep 2008
Margutti: Temporal variability of GRB early X-ray afterglows and GRB080319B prompt emission
Abstract: We performed the first systematic search for the minimum variability time
scale between 0.3 and 10 keV studying the 28 brightest early (<3000 s)
afterglows detected by Swift-XRT up to March 2008. We adopt the power spectrum
analysis in the time domain: unlike the Fourier spectrum, this is suitable to
study the rms variations at different time-scales. We find that early XRT
afterglows show variability in excess of the Poissonian noise level on
time-scales as short as about 1 s (rest frame value), with the shortest t_{min}
associated with the highest energy band. The gamma-ray prompt emission of
GRB080319B shows a characteristic average variability time-scale t_{var} of
about 1s; this parameter undergoes a remarkable evolution during the prompt
emission (BAT observation).
- 0810.2481from 14 Oct 2008
Wozniak: Gamma-Ray Burst at the extreme: "the naked-eye burst" GRB 080319B
Abstract: On 19 March 2008, the northern sky was the stage of a spectacular optical
transient that for a few seconds remained visible to the naked eye. The
transient was associated with GRB 080319B, a gamma-ray burst at a luminosity
distance of about 6 Gpc (standard cosmology), making it the most luminous
optical object ever recorded by human kind. We present comprehensive sky
monitoring and multi-color optical follow-up observations of GRB 080319B
collected by the RAPTOR telescope network covering the development of the
explosion and the afterglow before, during, and after the burst. The extremely
bright prompt optical emission revealed features that are normally not
detectable. The optical and gamma-ray variability during the explosion are
correlated, but the optical flux is much greater than can be reconciled with
single emission mechanism and a flat gamma-ray spectrum. This extreme optical
behavior is best understood as synchrotron self-Compton model (SSC). After a
gradual onset of the gamma-ray emission, there is an abrupt rise of the prompt
optical flux suggesting that variable self-absorption dominates the early
optical light curve. Our simultaneous multi-color optical light curves
following the flash show spectral evolution consistent with a rapidly decaying
red component due to large angle emission and the emergence of a blue forward
shock component from interaction with the surrounding environment. While
providing little support for the reverse shock that dominates the early
afterglow, these observations strengthen the case for the universal role of the
SSC mechanism in generating gamma-ray bursts.
- 0811.2997 from 19 Nov 2008
Zou: Expected high energy emission from GRB 080319B and origins of the GeV emission of GRBs 080514B, 080916C and 081024B
Abstract: We calculate the high energy (sub-GeV to TeV) prompt and afterglow emission
of GRB 080319B that was distinguished by a naked-eye optical flash and by an
unusual strong early X-ray afterglow. There are three possible sources for high
energy emission: the prompt optical and $\gamma$-ray photons IC scattered by
the internal shock electrons, the prompt photons IC scattered by the early
external reverse-forward shock electrons, and the higher band of the
synchrotron and the synchrotron self-Compton emission of the external shock.
There should have been in total $\sim 500$ high energy photons detectable for
the Large Area Telescope (LAT) onboard the Fermi satellite, and $> 30$ photons
of those with energy $> 10$ GeV. The $> 10$ GeV emission had a duration about
twice that of the soft $\gamma$-rays. AGILE could have observed these energetic
signals if it was not occulted by the Earth at that moment. The physical
origins of the high energy emission detected in GRB 080514B, GRB 080916C and
GRB 081024B are also discussed. These observations can be reasonably
interpreted by available high energy emission models based on our current
understanding of GRBs and afterglows.
- 0812.0318 from 1 Dec 2008
Zou: Clues from the prompt emission of GRB 080319B
Abstract: The extremely bright optical flash that accompanied GRB 080319B suggested, at
first glance, that the prompt $\gamma$-rays in this burst were produced by
Synchrotron self Compton (SSC). We analyze here the observed optical and
$\gamma$ spectrum. We find that the very strong optical emission poses, due to
self absorption, very strong constraints on the emission processes and put the
origin of the optical emission at a very large radius, almost inconsistent with
internal shock. Alternatively it requires a very large random Lorentz factor
for the electrons. We find that SSC could not have produced the prompt
$\gamma$-rays. We also show that the optical emission and the $\gamma$ rays
could not have been produced by synchrotron emission from two populations of
electron within the same emitting region. Thus we must conclude that the
optical and the $\gamma$-rays were produced in different physical regions. A
possible interpretation of the observations is that the $\gamma$-rays arose
from internal shocks but the optical flash resulted from external shock
emission. This would have been consistent with the few seconds delay observed
between the optical and $\gamma$-rays signals.
- 0812.0021from 1 Dec 2008
Kumar: Gamma-ray Burst 080319B: Evidence for Relativistic Turbulence, Not Internal Shocks
Abstract: We show that the excellent optical and gamma-ray data available for GRB
080319B rule out the internal shock model for the prompt emission. The data
instead point to a model in which the observed radiation was produced close to
the deceleration radius ($\sim10^{17}$ cm) by a turbulent source with random
Lorentz factors $\sim10$ in the comoving frame. The optical radiation was
produced by synchrotron emission from relativistic electrons, and the
gamma-rays by inverse Compton scattering of the synchrotron photons. The
gamma-ray emission originated both in eddies and in an inter-eddy medium,
whereas the optical radiation was mostly from the latter. Therefore, the
gamma-ray emission was highly variable whereas the optical was much less
variable. The model explains all the observed features in the prompt optical
and gamma-ray data of GRB 080319B. We are unable to determine with confidence
whether the energy of the explosion was carried outward primarily by particles
(kinetic energy) or magnetic fields. Consequently, we cannot tell whether the
turbulent medium was located in the reverse shock (we can rule out the forward
shock) or in a Poynting-dominated jet.
- 0901.2128 from 14 Jan 2009
Fan: Naked-eye optical flash from GRB 080319B: Tracing the decaying neutrons in the outflow
Abstract: For an unsteady baryonic gamma-ray burst (GRB) outflow, the fast and slow
proton shells collide with each other and produce energetic soft gamma-ray
emission. If the outflow has a significant neutron component, the
ultra-relativistic neutrons initially expand freely until decaying at a larger
radius. The late time proton shells ejected from the GRB central engine, after
powering the regular internal shocks, will sweep these $\beta-$decay products
and give rise to very bright UV/optical emission. The naked-eye optical flash
from GRB 080319B, an energetic explosion in the distant universe, can be well
explained in this way.
- GCN Circular #8883
Alexander Kappes for the IceCube collaboration (http://www.icecube.wisc.edu
) reports:
IceCube is a 1 km^3 neutrino telescope located at the geographic South
Pole sensitive to neutrinos above ~100 GeV. We used the data from
IceCube in its 9-string configuration to search for high-energy muon
neutrinos from the position of GRB 080319B (Racusin et al., GCN 7427)
using an unbinned likelihood method. The search was performed in a
narrow time window of 66 s (T_0 - 3.8s to T_0 + 62.2s) corresponding
to the observed prompt gamma-ray emission, and in a wider window of
about 5 minutes (T_0 - 173s to T_0 + 130 s).
We do not find any indications for a deviation from the background-
only hypothesis in either of the two time windows. Therefore, we use
the null result from the prompt window to place an upper limit (90%
C.L.) on the prompt muon neutrino flux from GRB 080319B of 9.0e-3 erg
cm^-2 in the energy range between 145 TeV and 2.1 PeV.
A corresponding paper has been submitted to ApJ. The preprint version
can be found at arXiv:0902.0131.
- 1005.1569 from 11 May 10
G. Chincarini et al.: The Sooner: a Large Robotic Telescope
D'Alessio, P. D'Avanzo, V. De Caprio, M. Della Valle, A. Fernandez-Soto, D. Fugazza, E. Giro, A. Gomboc, C. Guidorzi, D. Magrin, G. Malaspina,
L. Mankiewicz, R. Margutti, R. Mazzoleni, L. Nicastro, A. Riva, M. Riva, R. Salvaterra, P. Spano, M. Sperandio, M. Stefanon, G. Tosti, V. Testa
The approach of Observational Astronomy is mainly aimed at the construction of larger aperture telescopes, more sensitive detectors and broader
wavelength coverage. Certainly fruitful, this approach turns out to be not completely fulfilling the needs when phenomena related to the
formation of black holes (BH), neutron stars (NS) and relativistic stars in general are concerned. Recently, mainly through the Vela, Beppo-SAX
and Swift satellites, we reached a reasonable knowledge of the most violent events in the Universe and of some of the processes we believe are
leading to the formation of black holes (BH). We plan to open a new window of opportunity to study the variegated physics of very fast
astronomical transients, particularly the one related to extreme compact objects. The innovative approach is based on three cornerstones: 1)
the design (the conceptual design has been already completed) of a 3m robotic telescope and related focal plane instrumentation characterized
by the unique features: "No telescope points faster"; 2) simultaneous multi-wavelengths observations (photometry, spectroscopy o\&
polarimetry); 3) high time resolution observations. The conceptual design of the telescope and related instrumentation is optimized to address
the following topics: High frequency a-periodic variability, Polarization, High z GRBs, Short GRBs, GRB-Supernovae association,
Multi-wavelengths simultaneous photometry and rapid low dispersion spectroscopy. This experiment will turn the "exception" (like the optical
observations of GRB 080319B) to "routine".
- 1101.3952 from 21 Jan 11
R. Hascoët et al.: Origin of the bright prompt optical emission in the naked eye burst
The huge optical brightness of GRB 080319B (the "Naked Eye Burst) makes this event really challenging for models of the prompt GRB emission. In
the framework of the internal shock model, we investigate a scenario where the dominant radiative process is synchrotron emission and the high
optical flux is due to the dynamical properties of the relativistic outflow: if the initial Lorentz factor distribution in the jet is highly
variable, many internal shocks will form within the outflow at various radii. The most violent shocks will produce the main gamma-ray component
while the less violent ones will contribute at lower energy, including the optical range.
- 1111.0004 from 2 Nov 11
Lech Wiktor Piotrowski: Modelling of the "Pi of the Sky" detector
The ultimate goal of the "Pi of the Sky" apparatus is observation of optical flashes of astronomical origin and other light sources variable on
short timescales. We search mainly for optical emission of Gamma Ray Bursts, but also for variable stars, novae, etc. This task requires an
accurate measurement of the brightness, which is difficult as "Pi of the Sky" single camera has a field of view of about 20*20 deg. This causes
a significant deformation of a point spread function (PSF), reducing quality of measurements with standard algorithms. Improvement requires a
careful study and modelling of PSF, which is the main topic of the presented thesis. A dedicated laboratory setup has been created for
obtaining isolated, high quality profiles, which in turn were used as the input for mathematical models. Two different models are shown:
diffractive, simulating light propagation through lenses and effective, modelling the PSF shape in the image plane.
The effective model, based on PSF parametrization with selected Zernike polynomials describes the data well and was used in photometry and
astrometry analysis. No improvement compared to standard algorithms was observed in photometry, however more than factor of 2 improvement in
astrometry accuracy was reached for bright stars. Additionally, the model was used to recalculate limits on the optical precursor to GRB080319B
- a limit higher by 0.75 mag compared to previous calculations has been obtained.
The PSF model was also used to develop a dedicated tool to generate Monte Carlo samples of images corresponding to the "Pi of the Sky"
observations. The simulator allows for a detailed reproduction of the frame as seen by our cameras. A comparison of photometry performed on
real and simulated data resulted in very similar results, proving the simulator a worthy tool for future "Pi of the Sky" hardware and software
development.
- 1202.5322 from 27 Feb 12
Lech Wiktor Piotrowski: Constraints on the optical precursor to the naked-eye burst GRB080319B from Pi of the Sky observations
I present the results of the search for an optical precursor to the naked-eye burst - GRB080319B, which reached 5.87m optical peak luminosity
in the "Pi of the Sky" data. A burst of such a high brightness could have been preceded by an optical precursor luminous enough to be in
detection range of our experiment. The "Pi of the Sky" cameras observed the coordinates of the GRB for about 20 minutes prior to the explosion,
thus provided crucial data for the precursor search. No signal within 3 sigma limit was found. A limit of 12m (V-band equivalent) was set based
on the data combined from two cameras, the most robust limit to my knowledge for this precursor.
- 1206.3531 from 18 Jun 12
L. Resmi et al.: Gamma Ray Burst Prompt Emission Variability in Synchrotron and Synchrotron Self-Compton Lightcurves
Gamma Ray Burst prompt emission is believed to originate from electrons accelerated in a highly relativistic outflow. "Internal shocks" due to
collisions between shells ejected by the central engine is a leading candidate for electron acceleration. While synchrotron radiation is
generally invoked to interpret prompt gamma-ray emission within the internal shock model, synchrotron self-Compton (SSC) is also considered as
a possible candidate of radiation mechanism. In this case, one would expect a synchrotron emission component at low energies, and the naked-eye
GRB 080319B has been considered as such an example. In the view that the gamma-ray lightcurve of GRB 080319B is much more variable than its
optical counterpart, in this paper we study the relative variability between the synchrotron and SSC components. We develop a "top-down"
formalism by using observed quantities to infer physical parameters, and subsequently to study the temporal structure of synchrotron and SSC
components of a GRB. We complement the formalism with a "bottom-up" approach where the synchrotron and SSC lightcurves are calculated through a
Monte-Carlo simulations of the internal shock model. Both approaches lead to the same conclusion. Small variations in the synchrotron
lightcurve can be only moderately amplified in the SSC lightcurve. The SSC model therefore cannot adequately interpret the gamma-ray emission
properties of GRB 080319B.
- 1206.5605 from 26 Jun 12
Barbara Patricelli et al.: Analysis of GRB 080319B and GRB 050904 within the fireshell model: evidence for a broader spectral energy distribution
Vereshchagin
(Shortened) GRB080319B, with an isotropic energy E_{iso}=1.32x10^{54}erg, and GRB050904, with E_{iso}=1.04x10^{54}erg, offer the possibility of
studying the spectral properties of the prompt radiation of two of the most energetic Gamma-Ray Bursts (GRBs). This allows us to probe the
validity of the fireshell model for GRBs beyond 10^{54}erg, well outside the energy range where it has been successfully tested up to now
(10^{49}-10^{53}erg). We find that in the low energy region, the prompt emission spectra observed by Swift BAT reveals more power than
theoretically predicted. The opportunities offered by these observations to improve the fireshell model are outlined. One of the distinguishing
features of the fireshell model is that it relates the observed spectra to the spectrum in the comoving frame of the fireshell. Originally, a
fully radiative condition and a comoving thermal spectrum were adopted. An additional power-law in the comoving thermal spectrum is required
[...] in the fireshell model for GRBs 080319B and 050904. A new phenomenological parameter \alpha is correspondingly introduced in the model.
We perform numerical simulations of the prompt emission in the Swift BAT bandpass by assuming different values of \alpha [...]. We compare them
with the GRB080319B and GRB050904 observed time-resolved spectra, as well as with their time-integrated spectra and light curves. Although
GRB080319B and GRB050904 are at very different redshifts (z=0.937 and z=6.29 respectively), a value of \alpha=-1.8 leads for both of them to a
good agreement between the numerical simulations and the observed BAT light curves, time-resolved and time-integrated spectra. Such a modified
spectrum is also consistent with the observations of previously analyzed less energetic GRBs and reasons for this additional agreement are
given. Perspectives for future low energy missions are outlined.
- 1211.5673 from 27 Nov 12
Xiao-Hong Cui et al.: Delayed Onset and Fast Rise of Prompt Optical-UV Emission from Gamma-Ray Bursts in Molecular Clouds
Observations imply that long \gamma-ray bursts (GRBs) are originated from explosions of massive stars, therefore they may occur in the
molecular clouds where their progenitors were born. We show here that the prompt optical-UV emission from GRBs may be delayed due to the dust
extinction, which can well explain the observed optical delayed onset and fast rise in GRB 080319B. The density and the size of the molecular
cloud around GRB 080319B are roughly constrained to be \sim10^3cm^{-3} and \sim 8pc, respectively. We also investigate the other GRBs with
prompt optical-UV data, and find similar values of the densities and sizes of the local molecular clouds. The future observations of prompt
optical-UV emission from GRBs in subsecond timescale, e.g., by UFFO-Pathfinder and SVOM-GWAC, will provide more evidence and probes of the
local GRB environments.
- 1308.2868 from 14 Aug 13
Da-Bin Lin et al.: Revisiting the Light Curves of Gamma-ray Bursts in the Relativistic Turbulence Model
Rapid temporal variability has been widely observed in the light curves of gamma-ray bursts (GRBs). One possible mechanism for such variability
is related to the relativistic eddies in the jet. In this paper, we include the contribution of the inter-eddy medium together with the eddies
to the gamma-ray emission. We show that the gamma-ray emission can either lead or lag behind the observed synchrotron emission, where the
latter originates in the inter-eddy medium and provides most of seed photons for producing gamma-ray emission through the inverse-Compton
scattering. As a consequence, we argue that the lead/lag found in non-stationary short-lived light curves may not reveal the intrinsic lead/lag
of different emission components. In addition, our results may explain the lead of gamma-ray emission with respect to optical emission observed
in GRB 080319B.
- 1311.2183 from 12 Nov 13
Si-Yao Xu et al.: Prompt Optical Emission from Gamma-ray Bursts with Non-single Timescale Variability of Central Engine Activities
The complete high-resolution lightcurves of GRB 080319B present an opportunity for detailed temporal analysis of the prompt optical emission.
With a two-component distribution of initial Lorentz factors, we simulate the dynamical process of the ejected shells from the central engine
in the framework of the internal shock model. The emitted radiation are decomposed into different frequency ranges for a temporal correlation
analysis between the lightcurves in different energy bands. The resulting prompt optical and gamma-ray emission show similar temporal profiles,
both as a superposition of a slow variability component and a fast variability component, except that the gamma-ray lightcurve is much more
variable than its optical counterpart. The variability features in the simulated lightcurves and the strong correlation with a time lag between
the optical and gamma-ray emission are in good agreement with the observations of GRB 080319B. Our simulations suggest that the variations seen
in the lightcurves stem from the temporal structure of the shells injected from the central engine of gamma-ray bursts. The future high
temporal resolution observations of prompt optical emission from GRBs, e.g., by UFFO-Pathfinder and SVOM-GWAC, provide a useful tool to
investigate the central engine activity.
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