- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 26 Mar 12 01:20:49 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 518626, Seg_Num: 0
GRB_RA: 273.925d {+18h 15m 42s} (J2000),
273.902d {+18h 15m 36s} (current),
274.018d {+18h 16m 04s} (1950)
GRB_DEC: +69.278d {+69d 16' 41"} (J2000),
+69.283d {+69d 16' 58"} (current),
+69.259d {+69d 15' 31"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 2293 [cnts] Image_Peak=130 [image_cnts]
TRIGGER_DUR: 0.512 [sec]
TRIGGER_INDEX: 121 E_range: 15-50 keV
BKG_INTEN: 28837 [cnts]
BKG_TIME: 4815.96 SOD {01:20:15.96} UT
BKG_DUR: 8 [sec]
GRB_DATE: 16012 TJD; 86 DOY; 12/03/26
GRB_TIME: 4829.28 SOD {01:20:29.28} UT
GRB_PHI: -119.78 [deg]
GRB_THETA: 15.33 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 10.14 [sigma]
IMAGE_SIGNIF: 7.23 [sigma]
MERIT_PARAMS: +1 +0 +0 -1 +1 -3 +0 +0 -2 +0
SUN_POSTN: 5.32d {+00h 21m 16s} +2.30d {+02d 18' 01"}
SUN_DIST: 88.35 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.49d {+02h 41m 58s} +17.76d {+17d 45' 37"}
MOON_DIST: 85.15 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 99.52, 28.39 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 63.31, 86.91 [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 = 74.21,-7.93 [deg].
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 26 Mar 12 01:22:02 UT
NOTICE_TYPE: Swift-XRT Position
TRIGGER_NUM: 518626, Seg_Num: 0
GRB_RA: 273.9022d {+18h 15m 36.52s} (J2000),
273.8795d {+18h 15m 31.07s} (current),
273.9948d {+18h 15m 58.74s} (1950)
GRB_DEC: +69.2593d {+69d 15' 33.4"} (J2000),
+69.2639d {+69d 15' 50.1"} (current),
+69.2401d {+69d 14' 24.4"} (1950)
GRB_ERROR: 5.1 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 2.01e-09 [erg/cm2/sec]
GRB_SIGNIF: 9.32 [sigma]
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 4888.82 SOD {01:21:28.82} UT, 59.5 [sec] since BAT Trigger Time
TAM[0-3]: 327.64 237.22 261.60 243.47
AMPLIFIER: 2
WAVEFORM: 134
SUN_POSTN: 5.32d {+00h 21m 16s} +2.30d {+02d 18' 02"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.50d {+02h 42m 01s} +17.76d {+17d 45' 45"}
MOON_DIST: 85.17 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 99.50, 28.39 [deg] galactic lon,lat of the burst
ECL_COORDS: 63.26, 86.93 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: The XRT position is 1.21 arcmin from the BAT position.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 26 Mar 12 01:22:18 UT
NOTICE_TYPE: Swift-XRT Image
TRIGGER_NUM: 518626, Seg_Num: 0
GRB_RA: 273.9022d {+18h 15m 36.5s} (J2000),
273.8795d {+18h 15m 31.0s} (current),
273.9948d {+18h 15m 58.7s} (1950)
GRB_DEC: +69.2593d {+69d 15' 33.4"} (J2000),
+69.2639d {+69d 15' 50.1"} (current),
+69.2401d {+69d 14' 24.4"} (1950)
GRB_ERROR: 5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN: 87 [cnts]
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 4888.82 SOD {01:21:28.82} UT, 59.5 [sec] since BAT Trigger Time
CENTROID_X: 292.15, raw= 292 [pixels]
CENTROID_Y: 256.39, raw= 256 [pixels]
ROLL: 87.81 [deg]
GAIN: 1
MODE: 3, Long Image mode
WAVEFORM: 134
EXPO_TIME: 2.50 [sec]
GRB_POS_XRT_Y: -98.06
GRB_POS_XRT_Z: -27.20
IMAGE_URL: sw00518626000msxps_rw.img
SUN_POSTN: 5.32d {+00h 21m 16s} +2.30d {+02d 18' 02"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.51d {+02h 42m 01s} +17.76d {+17d 45' 47"}
MOON_DIST: 85.17 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 99.50, 28.39 [deg] galactic lon,lat of the burst
ECL_COORDS: 63.26, 86.93 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 26 Mar 12 01:22:26 UT
NOTICE_TYPE: Swift-XRT Processed Image
TRIGGER_NUM: 518626, Seg_Num: 0
GRB_RA: 273.9022d {+18h 15m 36.5s} (J2000),
273.8795d {+18h 15m 31.0s} (current),
273.9948d {+18h 15m 58.7s} (1950)
GRB_DEC: +69.2593d {+69d 15' 33.4"} (J2000),
+69.2639d {+69d 15' 50.1"} (current),
+69.2401d {+69d 14' 24.4"} (1950)
GRB_ERROR: 5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN: 87 [cnts]
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 4888.82 SOD {01:21:28.82} UT, 59.5 [sec] since BAT Trigger Time
CENTROID_X: 292.15, raw= 292 [pixels]
CENTROID_Y: 256.39, raw= 256 [pixels]
ROLL: 87.81 [deg]
GAIN: 1
MODE: 3, Long Image mode
WAVEFORM: 134
EXPO_TIME: 2.50 [sec]
GRB_POS_XRT_Y: -98.06
GRB_POS_XRT_Z: -27.20
IMAGE_URL: sw00518626000msxps_rw.img
SUN_POSTN: 5.32d {+00h 21m 16s} +2.30d {+02d 18' 03"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.51d {+02h 42m 02s} +17.76d {+17d 45' 48"}
MOON_DIST: 85.17 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 99.50, 28.39 [deg] galactic lon,lat of the burst
ECL_COORDS: 63.26, 86.93 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Processed Image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 26 Mar 12 01:24:23 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 518626, Seg_Num: 0
GRB_RA: 273.925d {+18h 15m 42s} (J2000),
273.902d {+18h 15m 36s} (current),
274.018d {+18h 16m 04s} (1950)
GRB_DEC: +69.278d {+69d 16' 41"} (J2000),
+69.283d {+69d 16' 58"} (current),
+69.259d {+69d 15' 31"} (1950)
GRB_DATE: 16012 TJD; 86 DOY; 12/03/26
GRB_TIME: 4829.28 SOD {01:20:29.28} UT
TRIGGER_INDEX: 121
GRB_PHI: -119.78 [deg]
GRB_THETA: 15.33 [deg]
DELTA_TIME: -51.00 [sec]
TRIGGER_DUR: 0.512 [sec]
SOLN_STATUS: 0x3
RATE_SIGNIF: 10.14 [sigma]
IMAGE_SIGNIF: 7.23 [sigma]
LC_URL: sw00518626000msb.lc
SUN_POSTN: 5.32d {+00h 21m 17s} +2.30d {+02d 18' 04"}
SUN_DIST: 88.35 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.52d {+02h 42m 05s} +17.77d {+17d 46' 01"}
MOON_DIST: 85.16 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 99.52, 28.39 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 63.31, 86.91 [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 = 74.21,-7.93 [deg].
- GCN Circular #13105
M. H. Siegel (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
N. Gehrels (NASA/GSFC), D. Grupe (PSU), E. A. Hoversten (PSU),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-OAB/PSU) and
C. A. Swenson (PSU) report on behalf of the Swift Team:
At 01:20:29 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120326A (trigger=518626). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 273.925, +69.278 which is
RA(J2000) = 18h 15m 42s
Dec(J2000) = +69d 16' 41"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single FRED
structure with a duration of about 40 sec. The peak count rate
was ~8000 counts/sec (15-350 keV), at ~4 sec after the trigger.
The XRT began observing the field at 01:21:28.8 UT, 59.5 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 273.90195,
69.26028 which is equivalent to:
RA(J2000) = 18h 15m 36.47s
Dec(J2000) = +69d 15' 37.0"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 70 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 5.24
x 10^20 cm^-2 (Kalberla et al. 2005).
The initial flux in the 2.5 s image was 2.01e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White
filter starting 67 seconds after the BAT trigger. No credible
afterglow candidate has been found in the initial data products. No
afterglow is seen in the 2.7'x2.7' sub-image. The 8'x8' region for the
list of sources generated on-board covers 100% of the XRT error
circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to
E(B-V) of 0.05.
Burst Advocate for this burst is M. H. Siegel (siegel 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 NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 26 Mar 12 01:31:27 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 518626, Seg_Num: 0
POINT_RA: 273.880d {+18h 15m 31s} (J2000)
POINT_DEC: +69.287d {+69d 17' 12"} (J2000)
POINT_ROLL: 87.817d
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 5108.55 SOD {01:25:08.55} UT, 279.3 [sec] since BAT Trigger Time
FILTER: 7, U
BKG_MEAN: 0.440
N_STARS: 23
X_OFFSET: 626 [pixels]
Y_OFFSET: 687 [pixels]
X_MAX: 1585 [pixels]
Y_MAX: 1646 [pixels]
DET_THRESH: 6
PHOTO_THRESH: 3
SL_URL: sw00518626000msufc0279.fits
SUN_POSTN: 5.32d {+00h 21m 18s} +2.30d {+02d 18' 11"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.58d {+02h 42m 20s} +17.78d {+17d 46' 47"}
MOON_DIST: 85.17 [deg]
MOON_ILLUM: 11 [%]
GAL_COORDS: 99.53, 28.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 63.64, 86.91 [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: Mon 26 Mar 12 01:26:59 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 518626, Seg_Num: 0
POINT_RA: 273.880d {+18h 15m 31s} (J2000)
POINT_DEC: +69.287d {+69d 17' 12"} (J2000)
ROLL: 87.817d
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 4896.61 SOD {01:21:36.61} UT, 67.3 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 354417704
X_OFFSET: 946 [pixels]
Y_OFFSET: 1007 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 1106
Y_GRB_POS: 1167
BINNING_INDEX: 1
IM_URL: sw00518626000msuni0076.fits
SUN_POSTN: 5.32d {+00h 21m 17s} +2.30d {+02d 18' 07"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.54d {+02h 42m 11s} +17.77d {+17d 46' 18"}
MOON_DIST: 85.16 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 99.53, 28.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 63.64, 86.91 [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: Mon 26 Mar 12 01:25:01 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 518626, Seg_Num: 0
POINT_RA: 273.880d {+18h 15m 31s} (J2000)
POINT_DEC: +69.287d {+69d 17' 12"} (J2000)
POINT_ROLL: 87.817d
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 4896.61 SOD {01:21:36.61} UT, 67.3 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 3.746
N_STARS: 84
X_OFFSET: 624 [pixels]
Y_OFFSET: 544 [pixels]
X_MAX: 1583 [pixels]
Y_MAX: 1503 [pixels]
DET_THRESH: 16
PHOTO_THRESH: 9
SL_URL: sw00518626000msufc0067.fits
SUN_POSTN: 5.32d {+00h 21m 17s} +2.30d {+02d 18' 05"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.53d {+02h 42m 07s} +17.77d {+17d 46' 05"}
MOON_DIST: 85.16 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 99.53, 28.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 63.64, 86.91 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 26 Mar 12 01:27:06 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 518626, Seg_Num: 0
POINT_RA: 273.880d {+18h 15m 31s} (J2000)
POINT_DEC: +69.287d {+69d 17' 12"} (J2000)
ROLL: 87.817d
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 4896.61 SOD {01:21:36.61} UT, 67.3 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 354417704
X_OFFSET: 946 [pixels]
Y_OFFSET: 1007 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 1106
Y_GRB_POS: 1167
BINNING_INDEX: 1
IM_URL: sw00518626000msuni0076.fits
SUN_POSTN: 5.32d {+00h 21m 17s} +2.30d {+02d 18' 07"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.55d {+02h 42m 11s} +17.77d {+17d 46' 19"}
MOON_DIST: 85.16 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 99.53, 28.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 63.64, 86.91 [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: All 4 attachments are included.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 26 Mar 12 01:32:59 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 518626, Seg_Num: 0
POINT_RA: 273.880d {+18h 15m 31s} (J2000)
POINT_DEC: +69.287d {+69d 17' 12"} (J2000)
ROLL: 87.817d
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 5108.55 SOD {01:25:08.55} UT, 279.3 [sec] since BAT Trigger Time
FILTER: 7, U
EXPOSURE_ID: 354417916
X_OFFSET: 946 [pixels]
Y_OFFSET: 1007 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 1106
Y_GRB_POS: 1167
BINNING_INDEX: 1
IM_URL: sw00518626000msuni0288.fits
SUN_POSTN: 5.33d {+00h 21m 18s} +2.30d {+02d 18' 13"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.60d {+02h 42m 23s} +17.78d {+17d 46' 58"}
MOON_DIST: 85.17 [deg]
MOON_ILLUM: 11 [%]
GAL_COORDS: 99.53, 28.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 63.64, 86.91 [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: All 4 attachments are included.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 26 Mar 12 01:25:27 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 518626, Seg_Num: 0
POINT_RA: 273.880d {+18h 15m 31s} (J2000)
POINT_DEC: +69.287d {+69d 17' 12"} (J2000)
POINT_ROLL: 87.817d
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 4896.61 SOD {01:21:36.61} UT, 67.3 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 3.746
N_STARS: 84
X_OFFSET: 624 [pixels]
Y_OFFSET: 544 [pixels]
X_MAX: 1583 [pixels]
Y_MAX: 1503 [pixels]
DET_THRESH: 16
PHOTO_THRESH: 9
SL_URL: sw00518626000msufc0067.fits
SUN_POSTN: 5.32d {+00h 21m 17s} +2.30d {+02d 18' 05"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.53d {+02h 42m 08s} +17.77d {+17d 46' 08"}
MOON_DIST: 85.16 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 99.53, 28.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 63.64, 86.91 [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: Mon 26 Mar 12 01:31:10 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 518626, Seg_Num: 0
POINT_RA: 273.880d {+18h 15m 31s} (J2000)
POINT_DEC: +69.287d {+69d 17' 12"} (J2000)
POINT_ROLL: 87.817d
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 5108.55 SOD {01:25:08.55} UT, 279.3 [sec] since BAT Trigger Time
FILTER: 7, U
BKG_MEAN: 0.440
N_STARS: 23
X_OFFSET: 626 [pixels]
Y_OFFSET: 687 [pixels]
X_MAX: 1585 [pixels]
Y_MAX: 1646 [pixels]
DET_THRESH: 6
PHOTO_THRESH: 3
SL_URL: sw00518626000msufc0279.fits
SUN_POSTN: 5.32d {+00h 21m 18s} +2.30d {+02d 18' 11"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.58d {+02h 42m 19s} +17.78d {+17d 46' 46"}
MOON_DIST: 85.17 [deg]
MOON_ILLUM: 11 [%]
GAL_COORDS: 99.53, 28.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 63.64, 86.91 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
COMMENTS: The Pointing RA,Dec,Roll values came from the 1st SrcList Notice.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 26 Mar 12 01:32:28 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 518626, Seg_Num: 0
POINT_RA: 273.880d {+18h 15m 31s} (J2000)
POINT_DEC: +69.287d {+69d 17' 12"} (J2000)
ROLL: 87.817d
IMG_START_DATE: 16012 TJD; 86 DOY; 12/03/26
IMG_START_TIME: 5108.55 SOD {01:25:08.55} UT, 279.3 [sec] since BAT Trigger Time
FILTER: 7, U
EXPOSURE_ID: 354417916
X_OFFSET: 946 [pixels]
Y_OFFSET: 1007 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 1106
Y_GRB_POS: 1167
BINNING_INDEX: 1
IM_URL: sw00518626000msuni0288.fits
SUN_POSTN: 5.32d {+00h 21m 18s} +2.30d {+02d 18' 12"}
SUN_DIST: 88.36 [deg] Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN: 40.59d {+02h 42m 22s} +17.78d {+17d 46' 54"}
MOON_DIST: 85.17 [deg]
MOON_ILLUM: 11 [%]
GAL_COORDS: 99.53, 28.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 63.64, 86.91 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Image.
COMMENTS: The Pointing RA,Dec,Roll values came from the 1st Image Notice.
COMMENTS: The GRB Position came from the XRT Position Command.
COMMENTS: The image has 2x2 binning (compression).
- GCN Circular #13106
W. Rujopakarn (Steward) and H. Flewelling (IfA/Hawaii) report on
behalf of the ROTSE collaboration:
ROTSE-IIId, located at the Turkish National Observatory at
Bakirlitepe, Turkey, responded to GRB 120326A (Swift trigger 518626;
Siegel et al., GCN 13105), producing images beginning 9.9 s after the
GCN notice time. An automated response took the first image at
01:20:51.9 UT, 22.6 s after the burst, under fair conditions. We took
10 5-sec, 10 20-sec and 10 60-sec exposures. These unfiltered images
are calibrated relative to USNO A2.0 (R). Imaging is on going.
Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma Swift/BAT error circle or the XRT error circle, for both
single images and coadding into sets of 10. Individual images have
limiting magnitudes ranging from 14.7-16.7; we set the following
specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
01:20:51.9 01:20:56.9 5 14.7 22.6 N
01:20:51.9 01:22:59.9 128 16.3 22.6 Y
- GCN Circular #13107
Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR),
Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:
We imaged the field of GRB 120326A detected by SWIFT
(trigger 518626) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.
The observations started 133.1s after the GRB trigger
(119.3s after the notice). The elevation of the field increased from
49 degrees above horizon and weather conditions
were good.
We detect a new fading source in the error box given by SWIFT
We detected the candidate couterpart at the XRT position
mentioned by Siegel et al. (GCNC 13105)
at the following position (+/- 2 arcsec):
RA(J2000.0) = 18h 15m 37.06s
DEC(J2000.0) = +69d 15' 35.3"
OT was R~18.2 at 163s after GRB.
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
As the afterglow was not detected by UVOT, we suggest
a high redshift (but z<7) for this burst.
N.B. Galactic coordinates are lon= 99.5219 lat=+28.3852
and the galactic extinction in R band is about 0.1 magnitude
estimated from D. Schlegel et al. 1998ApJ...500..525S.
This message may be cited.
- GCN Circular #13108
Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR),
Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:
The TAROT observations are continuing after the optical
detection mentioned in the GCNC (13107):
start end Rmag
(min) (min)
2.22 3.21 18.2
24.91 40.66 19.1
That suggests a slow decay (alpha~0.35) of the optical
afterglow.
- GCN Circular #13109
A. LaCluyze, J. Haislip, K. Ivarsen, M. Maturi, D. Reichart, J. Moore, H.
T. Cromartie, R. Egger, A. Foster, N. Frank, M. Nysewander, A. Oza, E.
Speckhard, A.Trotter, and J. A. Crain report:
Skynet observed the Swift/XRT localization of GRB 120326A (Swift trigger
#518626) with the Dolomites Astronomical Observatory located at the Carlo
Magno Hotel Spa Resort in Italy. Observations in SDSS g',r',i' and z' began
93 seconds after the trigger (113 seconds after the burst). We detect an
optical transit at the position reported by Klotz et. al. (GCN 13107).
Stacking images and calibrating to USNO B1.0 stars yields the following:
Mean Time
Since triger Tel Exposures Filter Magnitude
37.23 m DAO 3 x 160 s g=A2 20.770
39.90 m DAO 4 x 160 s r=A2 19.868
51.48 m DAO 5 x 160 s i=A2 19.236
- GCN Circular #13110
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1040 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 120326A, 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 = 273.90451, +69.25998 which is equivalent
to:
RA (J2000): 18h 15m 37.08s
Dec (J2000): +69d 15' 35.9"
with an uncertainty of 1.8 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) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
- GCN Circular #13111
C. Guidorzi (U. Ferrara) reports on behalf of
the LJMU GRB group:
The 2-m Liverpool Telescope automatically observed
Swift GRB 120326A (Siegel et al. GCN Circ. 13105)
on March 26, from 01:34:07 UT, corresponding to
13.6 minutes after the BAT trigger time.
Within the XRT error circle we clearly detect the
optical afterglow (Klotz et al. GCN Circ. 13107,
13108; LaCluyze et al. GCN Circ 13109) with the
SDSS riz filters at the following position
18:15:37.13 +69:15:35.7 (J2000)
uncertainty of 0.3". We estimate the magnitude
of the afterglow as follows:
Mid time from Exp Filter Magnitude
GRB (min) (s)
---------------------------------------------
14.1 3x10 r 19.1 +- 0.2
44.8 120 r 19.6 +- 0.1
---------------------------------------------
Magnitudes are calibrated against nearby USNOB-1
stars.
- GCN Circular #13112
Walker, C., Court J., Duffy, R., Edwards T., Herath, M., Kirk, J.,
Patel, S., Prajs, S., Tunbridge, B., Williams, D., Wood, R., Wright,
P., Munoz-Darias, T., Knigge, C., Coriat, M. (University of
Southampton), Gimeno, R. (IAC, Tenerife), Gorosabel, J. (IAA-CSIC,
Granada), report:
We observed the Swift/XRT location of the GRB 120326A (Goad et al.,
GCNC 13110) using the IAC80 82cm telescope at Tenerife (Canary
Islands, Spain). We took a set
of VRI-band images from 02:23:20 UT to 05:47:06 UT. The optical
transient (Klotz et al., GCNC 13108) is clearly detected. After a
calibration using the USNO B1 catalogue, we detected an important
rebrightening from R=19.4 to R=18.4.
- GCN Circular #13113
B. Dintinjana and B. Mikuz on behalf of PIKA observing program at Crni=20
Vrh Observatory:
We observed the afterglow of GRB 120326A (Siegel et al., GCN 13105) with=20
60 cm Cichocki robotic telescope at Crni Vrh Observatory, Slovenia. The=20
series of twenty 60 second exposures with R filter started at 1:27:50UT,=20
440 seconds after the burst. We confirm optical afterglow at coordinates=20
by C. Guidorzi (GCN 13111).
Photometry results are given in table below. The table contains the time=20
since the Swift GRB detection to the middle of exposure in seconds, R=20
magnitude and photometric error. The magnitudes are derived using=20
comparison stars from the USNO-B1 catalogue. The 3-sigma limiting=20
magnitude in R filter is around magnitude 20.5 =B1 0.3
Time [s] R Mag Err.
----------------------------
440 18.51 0.2
507 19.07 0.2
574 19.21 0.3
641 19.75 0.4
708 19.63 0.6
775 19.10 0.2
842 19.48 0.3
909 19.19 0.2
976 19.77 0.4
1043 19.01 0.2
1110 19.11 0.2
1177 19.18 0.2
1244 19.62 0.3
1311 20.02 0.5
1379 19.35 0.3
1446 19.79 0.4
1513 19.38 0.3
1580 18.97 0.2
1647 19.42 0.3
1714 19.82 0.4
----------------------------
- GCN Circular #13114
N. P. M. Kuin (MSSL-UCL), S. Holland (STScI), and M. H. Siegel (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120326A
67 s after the BAT trigger (Siegel et al., GCN Circ. 13105).
A source consistent with the XRT position (Goad et al., GCN Circ. 13110
is detected in the initial UVOT exposures at position: RA (J2000)
= 18:15:37.13, Dec (J2000) = +69:15:35.36 or, in decimal degrees:
273.90471, 69.259822 with an uncertainty of 0.5" (90 % confidence).
The transient was initially increasing in brightness, and after a small
decay rebrightened around 10ks after the trigger. There is also some
indication of colour dependence of the time of rebrightening.
The detection in the UVOT uvw2 filter gives an upper limit for the
redshift of about z < 1.6 for this burst.
Preliminary detections and 3-sigma upper limits using the UVOT
photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 67 217 147 >20.0
white 3903 4103 197 20.16 +/- 0.12
v 4314 5949 393 >19.3
b 3697 5334 393 20.23 +/- 0.16
u 4929 5128 197 19.66 +/- 0.20
m2 4518 16222 1228 >21.2
w2 4109 5744 393 >21.0
w1 9527 10427 886 20.21 +/- 0.18
v 21959 22259 295 18.67 +/- 0.12
w2 21052 21952 886 21.26 +/- 0.32
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).
- GCN Circular #13115
J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.P. Osborne
(U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), G.
Stratta (ASDC), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and M.H.
Siegel report on behalf of the Swift-XRT team:
We have analysed 12 ks of XRT data for GRB 120326A (Siegel et al. GCN
Circ. 13105), from 65 s to 34.6 ks after the BAT trigger. The data
comprise 100 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Goad et al. (GCN. Circ 13110).
The late-time light curve (from T0+3.7 ks) can be modelled with an
initial power-law decay with an index of alpha=0.20 (+0.15, -0.11),
followed by a break at T+16.6 ks to an alpha of -1.47 (+0.76, -0.03).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 4.4 (+0.4, -0.3). The
best-fitting absorption column is 3.4 (+/-0.5) x 10^21 cm^-2, in
excess of the Galactic value of 5.2 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 1.89 (+/-0.10) and a
best-fitting absorption column of 9.1 (+2.3, -2.2) x 10^20 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.8 x 10^-11 (4.6 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 9.1 (+2.3, -2.2) x 10^20 cm^-2
Galactic foreground: 5.2 x 10^20 cm^-2
Excess significance: 2.9 sigma
Photon index: 1.89 (+/-0.10)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00518626.
This circular is an official product of the Swift-XRT team.
- GCN Circular #13117
Myungshin Im, Jae-Woo Kim, and Duho Kim (CEOU/Seoul National Univ.)
We observed GRB 120326A (Siegel et al., GCN 13105) in
g,r,i,z,Y filters using CQUEAN camera on the 2.1m Otto-Struve
telescope at McDonald Observatory, Texas, US.
The observation started at 2012-03-26 10:09:22 UT,
or about 8.8 hours after the BAT alert.
In all of the g,r,i,z,Y-band images with 300 sec
exposure time each, we clearly detect the afterglow
reported earlier (Klotz et al. GCN 13107,
Guidorzi et al. GCN 13111, Walker et al. GCN 13112,
Dintinjana et al. GCN 13113, Kuin et al. GCN 13114),
We thank Karl Gebhardt and Alysha Shugart for allowing us
to observe this object during their observing run.
We plan to perform additional observations.
- GCN Circular #13118
J. C. Tello, R. S=E1nchez-Ram=EDrez, J. Gorosabel, A. J. Castro-Tirado
(IAA-CSIC Granada), M. A. Rivero, G. G=F3mez-Velarde (GTC La Palma) and A.
Klotz (IRAP-CNRS-OMP), on behalf of a larger collaboration, report:
"Following the detection of the optical afterglow to GRB 120326A (Siegel
et al. GCNC 13105, Klotz et al. GCNC 13107), we have taken four spectra
(600s each) with the 10.4m GTC (+ OSIRIS) at the Spanish Observatorio del
Roque de los Muchachos (La Palma). The spectra, covering the range
4000-10000 A were taken starting 1.8 hr post burst, and reveal several
absorption features, including CIV 1548-1550, Fe II 2344, Fe II 2383,
Mg II 2796-
2804 at a common redshift of 1.798. We therefore suggest this to be the
redshift of GRB 120326A."
This message can be quoted.
- GCN Circular #13120
S. D. Barthelmy (GSFC), T. Sakamoto (GSFC/UMBC), C. B. Markwardt (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL),
G. Sato (ISAS), M. H. Siegel (PSU), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 120326A (trigger #518626)
(Siegel, et al., GCN Circ. 13105). The BAT ground-calculated position is
RA, Dec = 273.906, 69.248 deg, which is
RA(J2000) = 18h 15m 37.3s
Dec(J2000) = +69d 14' 54.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 91%.
The mask-weighted light curve shows a possible (2-sigma) precursor peak
at ~T-105 sec, and two definite precursor peaks (~30 sec wide each) at ~T-60 sec
and ~T-25 sec. The main FRED peak starts T_0, peaks at ~T+4 sec, and
returns to background at ~T+20 sec. T90 (15-350 keV) is 69.6 +- 8.3 sec
(estimated error including systematics).
The time-averaged spectrum from T-67.90 to T+22.56 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.41 +- 0.34,
and Epeak of 41.1 +- 6.9 keV (chi squared 55.8 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 2.6 +- 0.3 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+3.59 sec in the 15-150 keV band is
4.6 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index
of 2.06 +- 0.07 (chi squared 68.4 for 57 d.o.f.). 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/518626/BA/
- GCN Circular #13119
Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill
Observatory, Varkaus, Finland) report:
T17 (AstroCamp Observatory, Nerpio, Spain) CDK17 17 inch (0.43 m)
f/6.8 and FLI ProLine CCD camera were used to detect GRB 120326A
optical afterglow 1.7 hours after the burst trigger. The observations were
started at 2012-03-26 02:54:48 (UT) and stopped at 2012-03-26
03:10:24 (UT). Six unfiltered observations with 120s exposure time were
made. The afterglow was detected at following position RA 18:15:37.13
and DEC +69:15:35.6.
The following magnitude was obtained from the observations using
NOMAD1 1592-0145660 (R = 17.740) as the comparison:
Tmid(sec)+T0 Filter Exp (sec) Mag Mag err Limit
6125 unfiltered 6x120 19.0 0.2 20.0
A jpg image of the observation is available at the following URL link:
- GCN Circular #13121
Y. Urata (NCU) and K.Y. Huang (ASIAA) on behalf of EAFON
We observed the field of GRB 120326A (GCN 13105) in g, r, i, and z-bands
with the Lulin 1m telescope operated by IANCU. The observation was
started at 17.2 hrs after the GRB. The optical afterglow (GCN 13107,
13109, 13111) is clearly detected in all of the g,r,i,z-bands. The
afterglow is still keeping the brightness around r = 19.0 (at 18.7 hrs
after the GRB).
- GCN Circular #13122
X.-H. Zhao (YNAO), J. Mao (KASI/YNAO), D. Xu (WIS/NAOC), J.-M. Bai
(YNAO) report on behalf of a larger collaboration:
We observed the afterglow of GRB 120326A (Siegel et al., GCN 13105) with
the 2.4m Gao-Mei-Gu (GMG) telescope. Observations started at 19:03:32
UT on 2012-3-26 (i.e., ~17.7 hrs after the burst) . We found the
following magnitudes:
Start time post-burst (hr) Exp. (s) Filter Magnitude (err)
17.7 300 R 18.7 (0.1)
17.8 300 V 18.7 (0.1)
17.9 300 B 19.4 (0.1)
18.0 300 R 18.8 (0.1)
18.1 300 V 18.8 (0.1)
18.2 300 B 19.5 (0.1)
The magnitudes were calibrated with the NOMAD1 stars. Further
observations are planned.
We thank the GMG staff, especially W.-M. Yi, H. -Y. Gao and D. -Q.
Wang for performing these observations.
2012-03-27
zhaoxiaohong78
- GCN Circular #13126
Soulier J.-F. (Observatoire de Maisoncelles) reports
the observation of the afterglow of GRB 120326A
19.7 hours after the GRB using a 30cm F/4 telescope
at the Observatoire de Maisoncelles, France (IAU
observatory code is C10).
A CCD camera ST7XME and no filter were
used. A stack of images shows clearly the
presence of the afterglow that confirms the
rebrightening mentioned by Gorosabel et al.
(GCNC 13112):
Tgrb +
start end Rmag error
19.7h 20.7h 18.6 0.1
We used the star NOMAD1 1593-0145121
(ra,dec)=(273.9707306,+69.3063278)
as reference R=15.32. Magnitudes are not
corrected for galactic dust extinction.
- GCN Circular #13131
L.P. Xin, J. Y.Wei, Y.L. Qiu, J. Wang, J.S. Deng,
C. Wu, X. H. Han on behalf of EAFON report:
We began to observe GRB120326A (Siegel et al., GCN Circ. 13105)
with Xinglong TNT telescope in R-band at 20:47:11.734 (UT), 19.45 hours after
the burst. The optical counterpart (e.g. Klotz et al. GCN Cir 13107)
was clearly detected with a brightness of 18.56 mag relatively to USNO B1.0 R2 mag
Further observations are planed.
This message may be cited.
For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org:8080/grb/index.html
We thank Liang Ma for performing these observations.
- GCN Circular #13136
Y. Urata (NCU), K.Y. Huang, S. Takahashi (ASIAA), G. Petitpas (SMA)
on behalf of EAFON
We observed the field of GRB120326A(GCN 13105) using Sub-Millimeter
Array (SMA). The observation in 219 GHz was started at 2012 Mar 26,
10:15 and ended at 21:10 (UT). Our preliminary analysis shows a radio
counterpart at the position of optical afterglow(GCN 13107, 13109, 13111).
The averaged flux density during the observation is 3.1 +/- 0.5 mJy.
Further detail analysis and monitoring are ongoing.
- GCN Circular #13139
M. Jang, M. Im, (SNU), & Y. Urata (NCU) on behalf of EAFON
We observed GRB 120326A (120326A et al., GCN 13105)
in R-band with a 1 m telescope at Mt. Lemmon, Arizona, U.S.
The obsevation started at 09:06:33 2012-03-26 UT, ~ 8 hours
after the burst alert.
We totally took 6 frames with 300 sec of exposure time and found
a bright optical afterglow in each frame (Im et al. GCN 13117,
Klotz et al. GCN 13107, Guidorzi et al. GCN 13111, Walker et al. GCN 13112,
Dintinjana et al. GCN 13113, Kuin et al. GCN 13114).
Preliminary photometry values are shown below. The R magnitudes were calibrated
with three nearby USNO B1.0 stars, USNO-B1.0 1592-0143334, 1592-0143322,
and 1592-0143349
Mid-time[sec] R-mag Err
================================
27639 17.63 0.06
27964 17.53 0.04
28282 17.61 0.04
28601 17.84 0.03
28915 17.90 0.03
29239 18.08 0.03
We thank the LOAO operator, I. Baek for her assistance with this observation.
- GCN Circular #13142
U.Quadri, L.Strabla, R.Girelli and A.Quadri
report:
We imaged the field of GRB 120326A detected by SWIFT
(trigger 518626) Goad et al (GCNC 13110), with the robotic
telescope of (IAU station 565) Bassano Bresciano
Observatory (member of ISSP), Italy.
The observations had started 19h 58m and ended 26h 08m after the
GRB trigger,with our schmidt telescope D=320 mm F/D=3.1.
Weather conditions were good.
We co-added some series of 20 exposures of 120s takings for the
whole night between 26 and 27 March 2012.
We detected clearly the presence of the optical couterpart
(e.g. Klotz et al. GCNC 13107) that confirms the rebrightening
mentioned by Gorosabel et al.(GCNC 13112),
at the following position:
RA (J2000.0) = 18 15 37.19
DEC(J2000.0) = +69 15 35.5
The CCD unfiltered magnitude during all through the
observations has been 18.7 (+/- 0.2)
The magnitude has nearly been constant during
this period.
Magnitudes were estimated with the UCAC-3
catalog and are not corrected for galactic
dust extinction.
Lightcurve analisis is in progress,
further observations are planed.
This message may be cited.
- GCN Circular #13143
A. N. Morgan (UC Berkeley) reports:
We observed the field of GRB 120326A (Siegel et al., GCN 13105) with the
1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at
2012-03-27 09:25:19 UT, ~32.1 hours after the Swift Trigger. In mosaics
(effective exposure time of 1.31 hours) taken simultaneously in the J, H,
and Ks filters, we detect a source at the optical afterglow location (Klotz
et al., GCN 13107; LaCluyze et al., GCN 13109; Guidorzi et al., GCN 13111;
Walker et al., GCN 13112; Kuin et al., GCN 13114; Im et al., GCN 13117;
Hentunen et al., GCN 13119; Urata et al., GCN 13121; Zhao et al., GCN
13122; Soulier, GCN 13126; Jang et al., GCN 13139; Quadri et al., GCN
13142).
The preliminary photometry yields:
post burst
t_mid (hr) exp.(hr) filt mag m_err
33.58 1.31 J 17.5 0.1
33.58 1.31 H 16.7 0.1
33.58 1.31 Ks 16.0 0.2
All magnitudes are given in the Vega system, calibrated to 2MASS. No
correction for Galactic extinction has been made to the above reported
values. Further observations are ongoing.
- GCN Circular #13145
Andrew C. Collazzi (NASA/ORAU)
reports on behalf of the Fermi GBM Team:
"At 01:20:31.51 UT on March 26, 2012, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 120326A (trigger 354417633 / 120326056) which was
triggered and detected by Swift (Siegel et al., GCN 13105).
The on-ground calculated location, using the Fermi GBM trigger data,
is consistent with the locations seen by Swift.
The GBM light curve shows a single FRED-like event with a
duration (T90) of about 12 s (50-300 keV).
The time-averaged spectrum from T0-3.584 to T0+13.824 s
is fit equally well by a Band and Comptonized Power Law function.
For the Band function, the parameters are:
Epeak = 46.45 +/- 3.67 keV, alpha = -0.98 +/- 0.14, and beta = -2.53 +/- 0.15.
This results in a 1-s peak flux of 3.10 +/- 0.05 ph/s-cm^2 and a
yields a fluence (10-1000 keV) in this time interval
of (3.539 +/- 0.174)E-06 erg/cm^2. The C-Stat for this fit is
653.15 over 489 degrees of freedom.
For the Comptonized function, the parameters are:
Epeak = 55.46 +/- 2.61 keV, and alpha = -1.21 +/- 0.08.
This results in a 1-s peak flux of 3.08 +/- 0.05 ph/s-cm^2.
Which yields a fluence (10-1000 kev) in this time interval of
(3.027 +/- 0.091)E-06 erg/s-cm^2. The C-Stat for this fit is
654.83 over 490 degrees of freedom.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
- GCN Circular #13149
L.P. Xin, J. Y.Wei, Y.L. Qiu, J. Wang, J.S. Deng,
C. Wu, X. H. Han on behalf of EAFON report:
We began to reobserve GRB120326A (Siegel et al., GCN Circ. 13105)
with Xinglong TNT telescope in R-band at 20:30:50.7 (UT), Mar. 28th 2012.
43.7 hours after the burst. The optical counterpart (e.g. Klotz et al. GCN Cir 13107)
was still clearly detected with a brightness of R=19.32 mag, relatively to USNO B1.0 R2 mag.
Comparing to the observation last time (Xin et al. GCN Cir. 13131),
the brightness decayed by a magnitude of 0.76 mag during these two epoch.
Further observations are planed.
This message may be cited.
For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org:8080/grb/index.html
We thank Chunlan Lu for performing these observations.
xlp@bao.ac.cn
- GCN Circular #13150
L.P. Xin, J. Y.Wei, Y.L. Qiu, J. Wang, J.S. Deng,=20
C. Wu, X. H. Han on behalf of EAFON report:
We began to reobserve GRB120326A (Siegel et al., GCN Circ. 13105)
with Xinglong TNT telescope in R-band at 20:30:50.7 (UT), Mar. 27th 2012.=
=20
43.7 hours after the burst. The optical counterpart (e.g. Klotz et al. =
GCN Cir 13107)=20
was still clearly detected with a brightness of R=3D19.32 mag, relatively=
to USNO B1.0 R2 mag.=20
Comparing to the observation last time (Xin et al. GCN Cir. 13131),
the brightness decayed by a magnitude of 0.76 mag during these two epoch.
Further observations are planed.
This message may be cited.
For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org:8080/grb/index.html
We thank Chunlan Lu for performing these observations.
- GCN Circular #13155
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ),
K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima),
K. Ohta (Kyoto) and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME collaboration:
We observed the field of GRB 120326A (Siegel et al., GCNC 13105)
with the optical three color (g', Rc and Ic) CCD camera attached
to the Murikabushi 1m telescope of Ishigakijima Astronomical
Observatory.
The observation started on 2012-03-27 16:59:18 UT (~1.65 days after the
burst). We detected the previously reported afterglow (Klotz et al.,
GCNC 13107; Guidorzi, GCNC 13111) in g' and Rc bands.
Photometric results of the OT are listed below. We used GSC2.3 catalog
for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic
----------------------------------------------------------------------
1.68494 17:46:48 960.0 20.3 0.2 19.9 0.2 >18.93
----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
- GCN Circular #13160
U.Quadri, L.Strabla, R.Girelli and A.Quadri
report:
We reobserved GRB120326A (see GCNC 13142)
with the robotic telescope of (IAU station 565) Bassano Bresciano
Observatory (member of ISSP), Italy.
We began on 2012/03/27.988 - 46.4 hours after the burst.
and finished on 2012/03/28.117 - 49.5 hours after the burst.
We co-added a series of 80 exposures (120s each) takings for
whole night between 27 and 28 March 2012.
The afterglow was still detected. Unfiltered magnitude was decreasing
from 19.1 (+/-0.1) to 19.7 (+/-0.1) during this period.
Weather conditions were good.
Magnitudes were estimated with the UCAC-3
catalog and are not corrected for galactic
dust extinction.
Lightcurve analisis is in progress,
further observations are planed.
This message may be cited.
- GCN Circular #13170
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ),
K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima),
K. Ohta (Kyoto) and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME collaboration:
We observed the field of GRB 120326A (Siegel et al., GCNC 13105)
with the optical three color (g', Rc and Ic) CCD camera attached
to the Murikabushi 1m telescope of Ishigakijima Astronomical
Observatory.
The observation started on 2012-03-28 15:12:13 UT (~2.58 days after the
burst). We detected the previously reported afterglow (Klotz et al.,
GCNC 13107; Guidorzi, GCNC 13111; Kuroda et al., GCNC 13155) in g' and Rc
bands.
Photometric results of the OT are listed below. We used GSC2.3 catalog
for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic
----------------------------------------------------------------------
2.61348 16:03:53 1620.0 20.0 0.2 20.1 0.2 >18.9
----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
- GCN Circular #13172
U.Quadri, L.Strabla, R.Girelli and A.Quadri
report:
We imaged the field of GRB 120326A detected by SWIFT
(trigger 518626) Goad et al (GCNC 13110), with the robotic
telescope of (IAU station 565) Bassano Bresciano
Observatory (member of ISSP), Italy.
The observations had started 19h 58m and ended 26h 08m after the
GRB trigger,with our schmidt telescope D=320 mm F/D=3.1.
Weather conditions were good.
We co-added some series of 20 exposures of 120s takings for the
whole night between 26 and 27 March 2012.
We detected clearly the presence of the optical couterpart
(e.g. Klotz et al. GCNC 13107) that confirms the rebrightening
mentioned by Gorosabel et al.(GCNC 13112),
at the following position:
RA (J2000.0) = 18 15 37.19
DEC(J2000.0) = +69 15 35.5
The CCD unfiltered magnitude during all through the
observations has been 18.7 (+/- 0.2)
The magnitude has nearly been constant during
this period.
Magnitudes were estimated with the UCAC-3
catalog and are not corrected for galactic
dust extinction.
Lightcurve analisis is in progress,
further observations are planed.
This message may be cited.
- GCN Circular #13175
D. A. Perley (Caltech), K. Alatalo (UCB), and A. Horesh (Caltech) report:
We observed the position of GRB 120326A (Siegel et al., GCN 13105) with
the Combined Array for Research in Millimeter-Wave Astronomy (CARMA) at
a frequency of 92.5 GHz (3 mm) between 13:33 and 15:19 UT on 2012-03-30.
A bright point source is observed consistent with the X-ray and
optical positions (Goad et al., GCN 13110; Klotz et al., GCN 13107;
Guidorzi et al., GCN 13111), at (J2000):
18:15:37.14 +69:15:35.07 (+/- 0.4")
We measure a flux density of 3.2 +/- 0.4 mJy at the mean time of t =
4.55 days after the GRB trigger.
- GCN Circular #13176
W. Iwakiri, M. Tashiro, Y. Terada, T. Yasuda, K. Takahara, M. Asahina,
S. Kobayashi, A. Sakamoto (Saitama U.),
Y. Hanabata, T. Uehara, T. Kawano, K. Takaki, M. Mizuno, M. Ohno,
Y. Fukazawa (Hiroshima U.), S. Sugita (Nagoya U.), K. Yamaoka (Aoyama
Gakuin U.), M. Kokubun,
T. Takahashi (ISAS/JAXA), Y. E. Nakagawa (Waseda U.), N. Ohmori, M.
Akiyama,
M. Yamauchi (Univ. of Miyazaki), Y. Urata, P. Tsai (NCU),
K. Nakazawa, K. Makishima (Univ. of Tokyo),
on behalf of the Suzaku WAM team, report:
The long GRB 120326A (Swift/BAT trigger #518626 ; Siegel et al., GCN
13105) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers
an energy range of 50 keV - 5 MeV at 01:20:31.907 UT (=T0).
The observed light curve shows a single peak starting at T0-5 s, ending
at T0+10 s, with a duration (T90) of about 9 seconds. The fluence in 100
- 1000 keV was 1.61(+/-0.26) x 10^-6 erg/cm^2. The 1-s peak flux
measured from T0+3 s was 0.61(-0.44, +0.40) photons/cm^2/s in the same
energy range.
Preliminary result shows that the time-averaged spectrum from T0-5 s to
T0+10 s is well fitted by a single power-law with a photon index of 2.14
(-0.31, 0.45) (chi2/d.o.f = 11.1/14).
All the quoted errors are at statistical 90% confidence level, in which
the systematic uncertainties are not included.
The light curves for this burst will be available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
- GCN Circular #13177
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ),
K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima),
K. Ohta (Kyoto) and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME collaboration:
We observed the field of GRB 120326A (Siegel et al., GCNC 13105)
with the optical three color (g', Rc and Ic) CCD camera attached
to the Murikabushi 1m telescope of Ishigakijima Astronomical
Observatory.
The observation started on 2012-03-29 17:40:10 UT (~3.68 days after the
burst). We detected the previously reported afterglow (Klotz et al.,
GCNC 13107; Guidorzi, GCNC 13111; Kuroda et al., GCNC 13155, 13170)
in all the three bands.
Photometric results of the OT are listed below. We used GSC2.3 catalog
for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic Ic_err
----------------------------------------------------------------------
3.71188 18:25:35 4320.0 20.9 0.2 20.8 0.2 19.7 0.3
----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
- GCN Circular #13178
U.Quadri, L.Strabla, R.Girelli and A.Quadri
report:
Photometric optical measurements of GRB 120326A detected by SWIFT (trigger 518626)
M. H. Siegel et al (GCNC 13105) have been done using the Schmidt telescope 0.32m F/3.1
and Starlight CCD camera HX-516 applied at direct focus. 120 sec. exposure time and
2x2 binning were used for all photos. All exposure were unfiltered.
Every night flat field and dark have been captured and all images were corrected
with them. In order to capture faint objects 60 shots was added before measurement
MPO Canopus version 10.4.0.20 was used to perform differential photometry on
the reduced images.
began of period: 2012/03/26.945 - 21.3 hours after the burst.
end of period: 2012/03/29.103 - 73.1 hours after the burst.
-----------------
GSC1.2 STARS USED
-----------------
ID: 0442901998
ID: 0442901953
ID: 0442902070
ID: 0442901970
The photometric results as follow:
-------------------------
Date UTC Mag.
-------------------------
2012 03 26.94456 18.75
2012 03 26.96648 18.70
2012 03 26.98842 18.70
2012 03 27.01038 18.80
2012 03 27.03232 18.70
2012 03 27.05427 18.80
2012 03 27.07624 19.85
2012 03 27.10038 19.95
2012 03 28.03167 19.30
2012 03 28.05361 19.48
2012 03 28.05362 19.41
2012 03 28.07558 19.52
2012 03 29.02885 19.77
2012 03 29.04972 19.91
2012 03 29.07231 19.93
2012 03 29.09504 20.00
2012 03 29.10332 19.98
-------------------------
Images and analisis are available at the following address:
http://www.osservatoriobassano.org/archivio/grb/GRB120326A-Trig-518626-2012-03-26.htm
This message may be cited.
- GCN Circular #13181
T. Laskar, A. Zauderer, and E. Berger (Harvard) report:
"We observed the position of GRB 120326A (GCN 13105) with the EVLA at a
mean frequency of 21.9 GHz starting on 2012 March 31.51 UT (5.45 days after
the burst). We detect a radio counterpart consistent with the Swift-XRT
position (Goad et al., GCN 13110), the optical position (Klotz et al., GCN
13107; Guidorzi et al., GCN 13111; Kuin et al., GCN 13114), and the CARMA 3
mm position (Perley et al., GCN 13175) with a flux density of 1.36 mJy.
Further observations are planned."
- GCN Circular #13185
D.K. Sahu, G.C. Anupama (Indian Institute of Astrophysics, Bangalore)
and S.B. Pandey (ARIES, Nainital) report.
The optical afterglow of GRB 120326A (Siegel et al., GCN 13105)
was observed in Bessell R band, with the 2m. Himalayan Chandra Telescope of
the Indian Astronomical Observatory, Hanle, India. Observations were made
between 22:36 UT and 23:14 UT on 27/03/2012. The optical afterglow was
detected in our individual frames of 300sec each.
The preliminary R magnitudes of the optical afterglow
calibrated using nearby USNO B1.0 stars is as under:
------------------------------------------------------------------
Date Mid UT Mid time from Exp. R Magnitude
GRB(hrs) (sec)
------------------------------------------------------------------
23-03-2012 22:55 45.5750 5x300 19.68 +/-0.07
-------------------------------------------------------------------
- GCN Circular #13189
M.Tonincelli, G.Arici (Cima Rest obs.)
U.Quadri, L.Strabla, R.Girelli and A.Quadri (Bassano Bresciano Obs.)
report:
We imaged the field of GRB 120326A detected by SWIFT
(trigger 518626) Goad et al (GCNC 13110), with the telescope
D=508 mm F/D=5 of Cima Rest Observatory (IAU station B11), Italy
during a collaboration with Bassano Bresciano Observatory
(IAU station 565), Italy
The observations:
had started 5d 19h 49m after the burst (2012-03-31 at 21h 08m UTC)
and ended 6d 00h 33m after the burst (2012-04-01 at 01h 51m UTC)
We co-added 40 exposures of 300s each.
We detected very faint optical couterpart
of 21.8 (+/- 0.1) unfiltered CCD magnitude.
at the following coordinates:
RA (J2000.0) = 18 15 37.03
DEC(J2000.0) = +69 15 35.1
Magnitudes were estimated using USNO-B1.0
catalog and are not corrected for galactic
dust extinction.
This message may be cited.
- GCN Circular #13192
U.Quadri, L.Strabla, R.Girelli and A.Quadri
report:
Photometric optical measurements of GRB 120326A detected by SWIFT (trigger 518626)
M. H. Siegel et al (GCNC 13105) have been done using the Schmidt telescope 0.32m F/3.1
and Starlight CCD camera HX-516 applied at direct focus. 120 sec. exposure time and
2x2 binning were used for all photos. All exposure were unfiltered.
Every night flat field and dark have been captured and all images were corrected
with them. In order to capture faint objects 60 shots was added before measurement
MPO Canopus version 10.4.0.20 was used to perform differential photometry on
the reduced images.
began of period: 2012/03/26.945 - 21.3 hours after the burst.
end of period: 2012/03/29.103 - 73.1 hours after the burst.
-----------------
GSC1.2 STARS USED
-----------------
ID: 0442901998
ID: 0442901953
ID: 0442902070
ID: 0442901970
The photometric results as follow:
-------------------------
Date UTC Mag.
-------------------------
2012 03 26.94456 18.75
2012 03 26.96648 18.70
2012 03 26.98842 18.70
2012 03 27.01038 18.80
2012 03 27.03232 18.70
2012 03 27.05427 18.80
2012 03 27.07624 18.85
2012 03 27.10038 18.95
2012 03 28.03167 19.30
2012 03 28.05361 19.48
2012 03 28.05362 19.41
2012 03 28.07558 19.52
2012 03 29.02885 19.77
2012 03 29.04972 19.91
2012 03 29.07231 19.93
2012 03 29.09504 20.00
2012 03 29.10332 19.98
-------------------------
Images and analisis are available at the following address:
http://www.osservatoriobassano.org/archivio/grb/GRB120326A-Trig-518626-2012-03-26.htm
This message may be cited.
- GCN Circular #13201
V. Golovnya, L. Kizyun (Main Astronomical Observatory, Kyiv)
report:
We have undertaken the review of the sky area in vicinity of=20
GRB 120326AA (M.R. Goad et al., GCN Circ.13110) on=20
astronegatives, collected in Ukrainian NAS Main astronomical=20
observatory plate archive (1976-1996). All the plates with=20
the possible object appearance are digitized using Microtek=20
ScanMaker 9800XL TMA and Epson Expression 10000XL flatbed=20
scanners and have been placed into Golosiiv Plate Archive=20
database DBGPA with open access to them.
The list of plates is given in the table:
YYYYMMDD/TimeUT --Plates-- Ex. LimM Star USNOA2=20
19860529/234300 GUA040C000924A 18 14.90 1575-03932397
19860531/232820 GUA040C000931 25 15.65 1575-03932513
19860710/175702 TAS040A000019B 45 17.90 1575-03933870
19860710/175706 TAS040B000020 45 17.95 1575-03933903
19860716/205409 GUA040C000960 16 15.85 1575-03934841
19940726/200551 GUA040C002347 18 15.45 1575-03933972
Plates:
GUA040C =96the plates archive identifier of DWA (D/F=3D400/2000,
M=3D103"/mm) of the Ukrainian NAS Main Astro obs.
(Marsden's number - 83) the plate number [1].
TAS040A,-the plates archive identifier of DAZ (D/F=3D400/3000,
TAS040B M=3D68.8"/mm) of the Tashkent Astro obs.
(Marsden's number - 186) the plate number [1].
Ex. - Duration of the maximum exposure (minutes).
LimM - Limited V mag, derived in the 15 minutes area around
the location given in M.R.Goad et al. GCN Circ.13110:
RA(J2000): 18h 15m 37.08s, Dec(J2000): +69d 15' 35.9"
Star USNOA2 - Comparison star.
The preview images of 6 areas together with =20
the 35x15 min.of arc area from SkyMap can be found in =20
http://gua.db.ukr-vo.org/img/grb/120326A/index.html
The images with full resolution are available via e-mail on=20
demand.
References:
1.L.Pakuliak DATABASE of GOLOSIIV PLATE ARCHIVE (DBGPA V2.0),
http://gua.db.ukr-vo.org
- 1211.3115 from 15 Nov 12
T. D. Staley et al.: Automated rapid follow-up of Swift GRBs with AMI-LA
We present 15-GHz follow-up radio observations of eleven Swift gamma-ray burst (GRB) sources, obtained with the Arcminute Microkelvin Imager
Large Array (AMI-LA). The initial follow-up observation for each source was made in a fully automated fashion; as a result four observations
were initiated within five minutes of the GRB alert timestamp. These observations provide the first millijansky-level constraints on prolonged
radio emission from GRBs within the first hour post-burst. While no radio emission within the first six hours after the GRB is detected in this
preliminary analysis, radio afterglow is detected from one of the GRBs (GRB120326A) on a timescale of days. The observations were made as part
of an ongoing programme to use AMI-LA as a systematic follow-up tool for transients at radio frequencies. In addition to the preliminary
results, we explain how we have created an easily extensible automated follow-up system, describing new software tools developed for
astronomical transient alert distribution, automatic requesting of target-of-opportunity observations, and robotic control of the observatory.
- GCN Report 409.1
GCN_Report 409.1 has been posted:
http://gcn.gsfc.nasa.gov/reports/report_409_1.pdf
by M.H. Siegel
at PSU
titled: "Swift Observations of GRB 120326A"
- 1402.6545 from 27 Feb 14
S. J. Hou et al.: The origin of the plateau and late rebrightening in the afterglow of GRB 120326A
GRB 120326A is an unusual gamma-ray burst (GRB) which has a quite long plateau and a very late rebrightening both in X-ray and optical bands.
The similar behavior of the optical and X-ray light curves suggests that they maybe have a common origin. The long plateau starts from several
hundred seconds and ends at tens of thousands seconds. The peak time of the late rebrightening is about 30000 s. We analyze the energy
injection model by means of numerical and analytical solutions, considering both the wind environment and ISM environment for GRB afterglows.
We especially study the influence of the injection starting time, ending time, stellar wind density (or density of the circumburst
environment), and injection luminosity on the shape of the afterglow light curves, respectively. We find that the light curve is largely
affected by the parameters in the wind model. There is a "bump" at the late time only in the wind model too. In the wind case, it is
interesting that the longer the energy injected, the more obvious the rebrightening will be. We also find the peak time of bump is determined
by the stellar wind density. We use the late continuous injection model to interpret the unusual afterglow of GRB 120326A. The model can well
fit the observational data, however, we find that the time scale of the injection must be larger than ten thousands seconds. This implies that
the time scale of the central engine activity must be more than ten thousands seconds. This can give useful constraints on the central engine
of GRBs. We consider a new born millisecond pulsar with strong magnetic field as the central engine. On the other hand, our results suggest
that the circumburst environment of GRB 120326A is very likely a stellar wind.
- 1405.4331 from
Yuji Urata et al.: Synchrotron Self-inverse Compton Radiation From Reverse-shock on GRB120326A
We present multi-wavelength observations of a typical long duration GRB 120326A at z=1.798, including rapid observations using a submillimeter array (SMA), and a comprehensive monitoring in X-ray and optical. The SMA observation provided the fastest detection to date among seven submillimeter afterglows at 230 GHz. The prompt spectral analysis, using Swift and Suzaku yielded a spectral peak energy of Esrcpeak=107.8+15.3\u221215.3 keV and equivalent isotropic energy of Eiso as 3.18+0.40\u22120.32×1052 erg. The temporal evolution and spectral properties in the optical were consistent with the standard forward shock synchrotron with jet collimation (6\u2218.69±0\u2218.16). The forward shock modeling using a 2D relativistic hydrodynamic jet simulation also determined the reasonable burst explosion and the synchrotron radiation parameters for the optical afterglow. The X-ray light curve showed no apparent jet break and the temporal decay index relation between the X-ray and optical (\u03b1o\u2212\u03b1X=\u22121.45±0.10) indicated different radiation processes in the X-ray and optical. Introducing synchrotron self-inverse Compton radiation from reverse shock is a possible solution, and the detection and the slow decay of the afterglow in submillimeter supports that this is a plausible idea. The observed temporal evolution and spectral properties as well as forward shock modeling parameters, enabled to determine reasonable functions to describe the afterglow properties. Because half of events share similar properties in the X-ray and optical to the current event, GRB120326A will be a benchmarks with further rapid follow-ups, using submillimeter instruments such as SMA and ALMA.
- 1409.6467 from 24 Sep 14
A. Melandri et al.: The nature of the late achromatic bump in GRB 120326A
The long ${\it Swift}$ gamma-ray burst GRB 120326A at redshift $z=1.798$ exhibited a multi-band light curve with a striking feature: a
late-time, long-lasting achromatic rebrightening, rarely seen in such events. Peaking in optical and X-ray bands $\sim 35$ ks ($\sim 12.5$ ks
in the GRB rest frame) after the 70-s GRB prompt burst, the feature brightens nearly two orders of magnitude above the underlying optical
power-law decay. Modelling the multiwavelength light curves, we investigate possible causes of the rebrightening in the context of the standard
fireball model. We exclude a range of scenarios for the origin of this feature: reverse-shock flash, late-time forward shock peak due to the
passage of the maximal synchrotron frequency through the optical band, late central engine optical/X-ray flares, interaction between the
expanding blast wave and a density enhancement in the circumburst medium and gravitational microlensing. Instead we conclude that the
achromatic rebrightening may be caused by a refreshed forward shock or a geometrical effect. In addition, we identify an additional component
after the end of the prompt emission, that shapes the observed X-ray and optical light curves differently, ruling out a single overall emission
component to explain the observed early time emission.
Previous IAU Circulars 