- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sun 10 May 09 00:23:18 UT
NOTICE_TYPE: Fermi-LAT Update Position
RECORD_NUM: 2
TRIGGER_NUM: 263607783
GRB_RA: 333.400d {+22h 13m 36s} (J2000),
333.532d {+22h 14m 08s} (current),
332.695d {+22h 10m 47s} (1950)
GRB_DEC: -26.767d {-26d 45' 59"} (J2000),
-26.720d {-26d 43' 11"} (current),
-27.015d {-27d 00' 52"} (1950)
GRB_ERROR: 7.00 [arcmin radius, statistical only]
GRB_INTEN_TOT: 213 [cnts]
GRB_INTEN1: 168 [cnts] (0-100 MeV)
GRB_INTEN2: 165 [cnts] (0.1-1 GeV)
GRB_INTEN3: 40 [cnts] ( 1-10 GeV)
GRB_INTEN4: 8 [cnts] (10-up GeV)
INTEG_DUR: 0.002 [sec]
FIRST_PHOTON: 1380.62 SOD {00:23:00.62} UT
LAST_PHOTON: 1383.18 SOD {00:23:03.18} UT
TRIGGER_INDEX: 0
GRB_DATE: 14961 TJD; 130 DOY; 09/05/10
GRB_TIME: 1381.22 SOD {00:23:01.22} UT
GRB_PHI: 230.70 [deg]
GRB_THETA: 13.87 [deg]
SOLN_STATUS: 0x30000002
BURST_ID: 0x10028
TEMP_TEST_STAT: 464.25 (log(prob), time domain)
IMAGE_TEST_STAT: 538.00 (log(prob), image domain)
SUN_POSTN: 47.04d {+03h 08m 10s} +17.60d {+17d 36' 11"}
SUN_DIST: 83.93 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 235.86d {+15h 43m 28s} -24.31d {-24d 18' 17"}
MOON_DIST: 85.61 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.27,-54.97 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 325.63,-14.72 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-LAT Coordinates.
COMMENTS: The starting/seed location came from LAT.
COMMENTS: An energy cut was applied to the gammas used for the localization.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sun 10 May 09 00:23:20 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 48
TRIGGER_NUM: 263607781
GRB_RA: 340.783d {+22h 43m 08s} (J2000),
340.914d {+22h 43m 39s} (current),
340.081d {+22h 40m 19s} (1950)
GRB_DEC: -33.333d {-33d 19' 59"} (J2000),
-33.284d {-33d 17' 02"} (current),
-33.596d {-33d 35' 43"} (1950)
GRB_ERROR: 4.00 [deg radius, statistical plus systematic]
GRB_INTEN: 1382 [cnts/sec]
DATA_SIGNIF: 45.70 [sigma]
INTEG_TIME: 0.512 [sec]
GRB_DATE: 14961 TJD; 130 DOY; 09/05/10
GRB_TIME: 1379.97 SOD {00:22:59.97} UT
GRB_PHI: 255.00 [deg]
GRB_THETA: 20.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO: 0.40
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 95% GRB
2nd_MOST_LIKELY: 4% Generic Transient
DETECTORS: 0,0,0, 1,0,0, 1,0,1, 0,0,0, 0,0,
SUN_POSTN: 47.04d {+03h 08m 10s} +17.60d {+17d 36' 11"}
SUN_DIST: 81.00 [deg] Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN: 235.87d {+15h 43m 28s} -24.31d {-24d 18' 18"}
MOON_DIST: 88.39 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 12.39,-61.72 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 329.17,-23.25 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 105.25,25.43 [deg].
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SIMBAD_NED NOTICE
NOTICE_DATE: Sun May 10 00:23:34 UTC 2009
NOTICE_TYPE: Swift-BAT Position search
TRIGGER_NUM: 351588
RA: 333.5550 (J2000)
DEC: -26.6056 (J2000)
SIMBAD search for BAT_RA,Dec=333.5550,-26.6056,radius=10.0arcmin
Num RA Dec Name Type Num_Pub Distance
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Sun 10 May 09 00:23:59 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 58
TRIGGER_NUM: 263607781
GRB_RA: 338.350d {+22h 33m 24s} (J2000),
338.483d {+22h 33m 56s} (current),
337.640d {+22h 30m 34s} (1950)
GRB_DEC: -33.530d {-33d 31' 47"} (J2000),
-33.482d {-33d 28' 53"} (current),
-33.788d {-33d 47' 16"} (1950)
GRB_ERROR: 1.00 [deg radius, statistical only]
DATA_SIGNIF: 48.10 [sigma]
DATA_INTERVAL: 0.512 [sec]
GRB_DATE: 14961 TJD; 130 DOY; 09/05/10
GRB_TIME: 1379.97 SOD {00:22:59.97} UT
GRB_PHI: 249.00 [deg]
GRB_THETA: 20.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 413 (Gnd S/W Version number)
SUN_POSTN: 47.04d {+03h 08m 10s} +17.60d {+17d 36' 11"}
SUN_DIST: 82.89 [deg] Sun_angle= 4.6 [hr] (West of Sun)
MOON_POSTN: 235.87d {+15h 43m 29s} -24.31d {-24d 18' 21"}
MOON_DIST: 86.50 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 12.24,-59.68 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 327.07,-22.61 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN NOTICE
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Sun 10 May 09 00:23:51 UT
NOTICE_TYPE: INTEGRAL SPI ACS Trigger
TRIGGER_NUM: 5867, Sub_Num: 0
GRB_INTEN: 17.33 [sigma]
GRB_TIME: 1380.01 SOD {00:23:00.01} UT
GRB_DATE: 14961 TJD; 130 DOY; 09/05/10
COMMENTS: INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:
+ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2009-05/2009-05-10T00-22-59.8166-12714-00007-0.lc
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:23:22 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 351588, Seg_Num: 0
GRB_RA: 333.555d {+22h 14m 13s} (J2000),
333.686d {+22h 14m 45s} (current),
332.851d {+22h 11m 24s} (1950)
GRB_DEC: -26.606d {-26d 36' 19"} (J2000),
-26.559d {-26d 33' 31"} (current),
-26.854d {-26d 51' 14"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 4726 [cnts] Image_Peak=154 [image_cnts]
TRIGGER_DUR: 0.256 [sec]
TRIGGER_INDEX: 126 E_range: 50-350 keV
BKG_INTEN: 22800 [cnts]
BKG_TIME: 1371.27 SOD {00:22:51.27} UT
BKG_DUR: 8 [sec]
GRB_DATE: 14961 TJD; 130 DOY; 09/05/10
GRB_TIME: 1380.48 SOD {00:23:00.48} UT
GRB_PHI: 20.28 [deg]
GRB_THETA: 46.07 [deg]
SOLN_STATUS: 0x20000003
RATE_SIGNIF: 145.48 [sigma]
IMAGE_SIGNIF: 7.48 [sigma]
MERIT_PARAMS: +1 +0 +0 -2 +3 -2 +0 +0 -11 +0
SUN_POSTN: 47.04d {+03h 08m 10s} +17.60d {+17d 36' 11"}
SUN_DIST: 83.74 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 235.87d {+15h 43m 28s} -24.31d {-24d 18' 18"}
MOON_DIST: 85.81 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.58,-55.08 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 325.83,-14.63 [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 = 65.09,-5.92 [deg].
COMMENTS:
COMMENTS: NOTE: This BAT event is temporally(1.0<100sec) coincident with the FERMI_LAT event (trignum=263607783).
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:24:42 UT
NOTICE_TYPE: Swift-XRT Nack-Position
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.607d {-26d 36' 23"} (J2000)
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1474.58 SOD {00:24:34.58} UT, 94.1 [sec] since BAT Trigger Time
COUNTS: 4 Min_needed= 20
STD_DEV: 0.00 Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER: 1 Max_iter_allowed= 4
ERROR_CODE: 1
COMMENTS: SWIFT-XRT Nack Position.
COMMENTS: No source found in the image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:27:16 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 351588, Seg_Num: 0
GRB_RA: 333.555d {+22h 14m 13s} (J2000),
333.686d {+22h 14m 45s} (current),
332.851d {+22h 11m 24s} (1950)
GRB_DEC: -26.606d {-26d 36' 19"} (J2000),
-26.559d {-26d 33' 31"} (current),
-26.854d {-26d 51' 14"} (1950)
GRB_DATE: 14961 TJD; 130 DOY; 09/05/10
GRB_TIME: 1380.48 SOD {00:23:00.48} UT
TRIGGER_INDEX: 126
GRB_PHI: 20.28 [deg]
GRB_THETA: 46.07 [deg]
DELTA_TIME: 38.00 [sec]
TRIGGER_DUR: 0.256 [sec]
SOLN_STATUS: 0x3
RATE_SIGNIF: 145.48 [sigma]
IMAGE_SIGNIF: 7.48 [sigma]
LC_URL: sw00351588000msb.lc
SUN_POSTN: 47.04d {+03h 08m 11s} +17.60d {+17d 36' 13"}
SUN_DIST: 83.74 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 235.90d {+15h 43m 36s} -24.31d {-24d 18' 40"}
MOON_DIST: 85.78 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.58,-55.08 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 325.83,-14.63 [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 = 65.09,-5.92 [deg].
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:27:34 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.607d {-26d 36' 23"} (J2000)
POINT_ROLL: 66.816d
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1477.80 SOD {00:24:37.80} UT, 97.3 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 3.192
N_STARS: 32
X_OFFSET: 367 [pixels]
Y_OFFSET: 578 [pixels]
X_MAX: 1326 [pixels]
Y_MAX: 1537 [pixels]
DET_THRESH: 15
PHOTO_THRESH: 8
SL_URL: sw00351588000msufc0097.fits
SUN_POSTN: 47.04d {+03h 08m 11s} +17.60d {+17d 36' 14"}
SUN_DIST: 83.73 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 235.90d {+15h 43m 37s} -24.31d {-24d 18' 42"}
MOON_DIST: 85.79 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.59,-55.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 325.84,-14.63 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:28:12 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.607d {-26d 36' 23"} (J2000)
POINT_ROLL: 66.816d
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1477.80 SOD {00:24:37.80} UT, 97.3 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 3.192
N_STARS: 32
X_OFFSET: 367 [pixels]
Y_OFFSET: 578 [pixels]
X_MAX: 1326 [pixels]
Y_MAX: 1537 [pixels]
DET_THRESH: 15
PHOTO_THRESH: 8
SL_URL: sw00351588000msufc0097.fits
SUN_POSTN: 47.04d {+03h 08m 11s} +17.60d {+17d 36' 14"}
SUN_DIST: 83.73 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 235.91d {+15h 43m 38s} -24.31d {-24d 18' 45"}
MOON_DIST: 85.78 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.59,-55.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 325.84,-14.63 [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: Sun 10 May 09 00:29:16 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.607d {-26d 36' 23"} (J2000)
ROLL: 66.816d
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1477.80 SOD {00:24:37.80} UT, 97.3 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 263607882
X_OFFSET: 686 [pixels]
Y_OFFSET: 897 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 846
Y_GRB_POS: 1057
BINNING_INDEX: 1
IM_URL: sw00351588000msuni0102.fits
SUN_POSTN: 47.05d {+03h 08m 11s} +17.60d {+17d 36' 15"}
SUN_DIST: 83.73 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 235.92d {+15h 43m 41s} -24.31d {-24d 18' 51"}
MOON_DIST: 85.77 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.59,-55.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 325.84,-14.63 [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: All 4 attachments are included.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:28:54 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.607d {-26d 36' 23"} (J2000)
ROLL: 66.816d
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1477.80 SOD {00:24:37.80} UT, 97.3 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 263607882
X_OFFSET: 686 [pixels]
Y_OFFSET: 897 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 846
Y_GRB_POS: 1057
BINNING_INDEX: 1
IM_URL: sw00351588000msuni0102.fits
SUN_POSTN: 47.05d {+03h 08m 11s} +17.60d {+17d 36' 15"}
SUN_DIST: 83.73 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 235.92d {+15h 43m 40s} -24.31d {-24d 18' 49"}
MOON_DIST: 85.78 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.59,-55.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 325.84,-14.63 [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/SIMBAD_NED NOTICE
NOTICE_DATE: Sun May 10 00:33:34 UTC 2009
NOTICE_TYPE: Swift-XRT Position search
TRIGGER_NUM: 351588
RA: 333.5519 (J2000)
DEC: -26.5834 (J2000)
SIMBAD search for XRT_RA,Dec=333.5519,-26.5834,radius=1.0arcmin
Num RA Dec Name Type Num_Pub Distance
NED search for XRT_RA,Dec=333.5519,-26.5834,radius=1.0arcmin
Num RA Dec Name Type Distance
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:33:30 UT
NOTICE_TYPE: Swift-XRT Position
TRIGGER_NUM: 351588, Seg_Num: 0
GRB_RA: 333.5519d {+22h 14m 12.45s} (J2000),
333.6833d {+22h 14m 43.99s} (current),
332.8482d {+22h 11m 23.57s} (1950)
GRB_DEC: -26.5834d {-26d 35' 00.2"} (J2000),
-26.5367d {-26d 32' 12.2"} (current),
-26.8319d {-26d 49' 54.8"} (1950)
GRB_ERROR: 3.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 1.00e-10 [erg/cm2/sec]
GRB_SIGNIF: 10.00 [sigma]
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1655.00 SOD {00:27:35.00} UT, 274.5 [sec] since BAT Trigger Time
TAM[0-3]: 100.00 100.00 100.00 100.00
AMPLIFIER: 1
WAVEFORM: 31
SUN_POSTN: 47.05d {+03h 08m 12s} +17.60d {+17d 36' 18"}
SUN_DIST: 83.74 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 235.96d {+15h 43m 50s} -24.32d {-24d 19' 16"}
MOON_DIST: 85.73 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.62,-55.07 [deg] galactic lon,lat of the burst
ECL_COORDS: 325.83,-14.60 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: TAM values, flux and significance fields are not valid
COMMENTS: This position was automatically generated on the ground using
COMMENTS: Photon Counting data telemetered via TDRSS (SPER data).
COMMENTS: See http://www.swift.ac.uk/sper/docs.php for details.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:27:34 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.607d {-26d 36' 23"} (J2000)
POINT_ROLL: 66.816d
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1477.80 SOD {00:24:37.80} UT, 97.3 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 3.192
N_STARS: 32
X_OFFSET: 367 [pixels]
Y_OFFSET: 578 [pixels]
X_MAX: 1326 [pixels]
Y_MAX: 1537 [pixels]
DET_THRESH: 15
PHOTO_THRESH: 8
SL_URL: sw00351588000msufc0097.fits
SUN_POSTN: 47.04d {+03h 08m 11s} +17.60d {+17d 36' 14"}
SUN_DIST: 83.73 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 235.90d {+15h 43m 37s} -24.31d {-24d 18' 42"}
MOON_DIST: 85.79 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.59,-55.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 325.84,-14.63 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN Circular #9331
E. A. Hoversten (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
M. M. Chester (PSU), D. Grupe (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (MSSL),
D. M. Palmer (LANL) and T. N. Ukwatta (GSFC/GWU) report on behalf of
the Swift Team:
At 00:23:00 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090510 (trigger=351588). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 333.555, -26.606 which is
RA(J2000) = 22h 14m 13s
Dec(J2000) = -26d 36' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a single spike
with a duration of about 0.5 sec. The peak count rate
was ~21000 counts/sec (15-350 keV), at 0 sec after the trigger.
The XRT began observing the field at 00:24:34.6 UT, 94.1 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 333.55195, -26.58345 which is
equivalent to:
RA(J2000) = 22h 14m 12.47s
Dec(J2000) = -26d 35' 00.4"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 81 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
1.66e+20 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 150 seconds with the White
filter starting 97 seconds after the BAT trigger. No credible
afterglow candidate has been found in the initial data products.
The 2.7'x2.7' sub-image does not include the position of the XRT
candidate. The 8'x8' region for the list of sources generated
on-board covers the XRT position and 100% of the BAT 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 0.02.
We note the existence of the galaxy 2dFGRS TGS176Z296 at
a distance of 140 arcsec from the XRT position.
Burst Advocate for this burst is E. A. Hoversten (hoversten 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: Sun 10 May 09 00:49:12 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.604d {-26d 36' 13"} (J2000)
POINT_ROLL: 66.815d
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1689.57 SOD {00:28:09.57} UT, 309.1 [sec] since BAT Trigger Time
FILTER: 7, U
BKG_MEAN: 0.939
N_STARS: 47
X_OFFSET: 127 [pixels]
Y_OFFSET: 338 [pixels]
X_MAX: 1566 [pixels]
Y_MAX: 1777 [pixels]
DET_THRESH: 8
PHOTO_THRESH: 4
SL_URL: sw00351588000msufc0309.fits
SUN_POSTN: 47.06d {+03h 08m 14s} +17.61d {+17d 36' 28"}
SUN_DIST: 83.74 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 236.11d {+15h 44m 25s} -24.35d {-24d 20' 45"}
MOON_DIST: 85.61 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.59,-55.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 325.84,-14.63 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SIMBAD_NED NOTICE
NOTICE_DATE: Sun May 10 00:49:50 UTC 2009
NOTICE_TYPE: Swift-XRT Position search
TRIGGER_NUM: 351588
RA: 333.5523 (J2000)
DEC: -26.5831 (J2000)
SIMBAD search for XRT_RA,Dec=333.5523,-26.5831,radius=1.0arcmin
Num RA Dec Name Type Num_Pub Distance
NED search for XRT_RA,Dec=333.5523,-26.5831,radius=1.0arcmin
Num RA Dec Name Type Distance
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:49:44 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.604d {-26d 36' 13"} (J2000)
POINT_ROLL: 66.815d
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1689.57 SOD {00:28:09.57} UT, 309.1 [sec] since BAT Trigger Time
FILTER: 7, U
BKG_MEAN: 0.939
N_STARS: 47
X_OFFSET: 127 [pixels]
Y_OFFSET: 338 [pixels]
X_MAX: 1566 [pixels]
Y_MAX: 1777 [pixels]
DET_THRESH: 8
PHOTO_THRESH: 4
SL_URL: sw00351588000msufc0309.fits
SUN_POSTN: 47.06d {+03h 08m 14s} +17.61d {+17d 36' 28"}
SUN_DIST: 83.74 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 236.11d {+15h 44m 26s} -24.35d {-24d 20' 48"}
MOON_DIST: 85.61 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.59,-55.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 325.84,-14.63 [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: Sun 10 May 09 00:49:44 UT
NOTICE_TYPE: Swift-XRT Position UPDATE
TRIGGER_NUM: 351588, Seg_Num: 0
GRB_RA: 333.5523d {+22h 14m 12.55s} (J2000),
333.6837d {+22h 14m 44.09s} (current),
332.8486d {+22h 11m 23.67s} (1950)
GRB_DEC: -26.5831d {-26d 34' 59.1"} (J2000),
-26.5364d {-26d 32' 11.2"} (current),
-26.8316d {-26d 49' 53.7"} (1950)
GRB_ERROR: 2.4 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 1.00e-10 [erg/cm2/sec]
GRB_SIGNIF: 10.00 [sigma]
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1655.00 SOD {00:27:35.00} UT, 274.5 [sec] since BAT Trigger Time
TAM[0-3]: 100.00 100.00 100.00 100.00
AMPLIFIER: 1
WAVEFORM: 31
SUN_POSTN: 47.06d {+03h 08m 14s} +17.61d {+17d 36' 28"}
SUN_DIST: 83.75 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 236.11d {+15h 44m 26s} -24.35d {-24d 20' 48"}
MOON_DIST: 85.60 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.62,-55.07 [deg] galactic lon,lat of the burst
ECL_COORDS: 325.84,-14.60 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.
COMMENTS: TAM values, flux and significance fields are not valid
COMMENTS: This position was automatically generated on the ground using
COMMENTS: Photon Counting data telemetered via TDRSS (SPER data).
COMMENTS: See http://www.swift.ac.uk/sper/docs.php for details.
COMMENTS: This position was enhanced using UVOT field astrometry
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:49:12 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.604d {-26d 36' 13"} (J2000)
POINT_ROLL: 66.815d
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1689.57 SOD {00:28:09.57} UT, 309.1 [sec] since BAT Trigger Time
FILTER: 7, U
BKG_MEAN: 0.939
N_STARS: 47
X_OFFSET: 127 [pixels]
Y_OFFSET: 338 [pixels]
X_MAX: 1566 [pixels]
Y_MAX: 1777 [pixels]
DET_THRESH: 8
PHOTO_THRESH: 4
SL_URL: sw00351588000msufc0309.fits
SUN_POSTN: 47.06d {+03h 08m 14s} +17.61d {+17d 36' 28"}
SUN_DIST: 83.74 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 236.11d {+15h 44m 25s} -24.35d {-24d 20' 45"}
MOON_DIST: 85.61 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.59,-55.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 325.84,-14.63 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 00:50:35 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.604d {-26d 36' 13"} (J2000)
ROLL: 66.815d
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1689.57 SOD {00:28:09.57} UT, 309.1 [sec] since BAT Trigger Time
FILTER: 7, U
EXPOSURE_ID: 263608094
X_OFFSET: 686 [pixels]
Y_OFFSET: 897 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 846
Y_GRB_POS: 1057
BINNING_INDEX: 1
IM_URL: sw00351588000msuni0314.fits
SUN_POSTN: 47.06d {+03h 08m 14s} +17.61d {+17d 36' 29"}
SUN_DIST: 83.75 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 236.12d {+15h 44m 28s} -24.35d {-24d 20' 52"}
MOON_DIST: 85.60 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.59,-55.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 325.84,-14.63 [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: Sun 10 May 09 00:51:02 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 351588, Seg_Num: 0
POINT_RA: 333.572d {+22h 14m 17s} (J2000)
POINT_DEC: -26.604d {-26d 36' 13"} (J2000)
ROLL: 66.815d
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1689.57 SOD {00:28:09.57} UT, 309.1 [sec] since BAT Trigger Time
FILTER: 7, U
EXPOSURE_ID: 263608094
X_OFFSET: 686 [pixels]
Y_OFFSET: 897 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 846
Y_GRB_POS: 1057
BINNING_INDEX: 1
IM_URL: sw00351588000msuni0314.fits
SUN_POSTN: 47.06d {+03h 08m 14s} +17.61d {+17d 36' 29"}
SUN_DIST: 83.75 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 236.12d {+15h 44m 29s} -24.35d {-24d 20' 55"}
MOON_DIST: 85.59 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.59,-55.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 325.84,-14.63 [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: All 4 attachments are included.
- GCN Circular #9332
F. E. Marshall (GSFC) and E. A. Hoversten (PSU) report on behalf of the
Swift team:
UVOT took a second finding chart exposure of 250 seconds with the U filter starting
309 seconds after the BAT trigger for GRB 090510 (Hoversten et al.
GCN Circ. 9331). There is a candidate afterglow in the
rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 22:14:12.54 = 333.55227
DEC(J2000) = -26:34:58.4 = -26.58290
with a 90%-confidence error radius of about 0.69 arc sec. This position is 0.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.95 with a 1-sigma error of about 0.17. No information about
variability is available at this time. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.02.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Sun 10 May 09 01:32:39 UT
NOTICE_TYPE: Swift-UVOT Position
TRIGGER_NUM: 351588, Seg_Num: 0
GRB_RA: 333.5523d {+22h 14m 12.55s} (J2000),
333.6837d {+22h 14m 44.09s} (current),
332.8486d {+22h 11m 23.67s} (1950)
GRB_DEC: -26.5828d {-26d 34' 58.0"} (J2000),
-26.5361d {-26d 32' 10.1"} (current),
-26.8313d {-26d 49' 52.6"} (1950)
GRB_ERROR: 0.7 [arcsec radius, statistical only]
GRB_MAG: 18.95 +/- 0.17 [mag]
FILTER: 7, U
IMG_START_DATE: 14961 TJD; 130 DOY; 09/05/10
IMG_START_TIME: 1692.00 SOD {00:28:12.00} UT, 311.5 [sec] since BAT Trigger Time
SUN_POSTN: 47.09d {+03h 08m 21s} +17.62d {+17d 36' 56"}
SUN_DIST: 83.78 [deg] Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN: 236.51d {+15h 46m 02s} -24.41d {-24d 24' 49"}
MOON_DIST: 85.24 [deg]
MOON_ILLUM: 99 [%]
GAL_COORDS: 24.62,-55.07 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 325.84,-14.60 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT UVOT Position Notice.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: E(B-V) of 0.02
- GCN Circular #9334
Masanori Ohno(ISAS/JAXA), Veronique Pelassa(CNRS/IN2P3/LPTA) report
on behalf of the Fermi LAT team:
At 00:23:01.22 UT on 10 May 2009, the Fermi Large Area Telescope (LAT) triggered and located GRB 090510 (trigger 263607783 / 090510016).
Emission was observed in the LAT up to GeV energy band with a detection significance of more than 5 sigma.
The best LAT on-board localization is found to be
(RA,Dec=333.400, -26.767) with an error radius of 7 arcmin (statistical only).
This position is consistent with both Fermi/GBM and Swift/XRT position.
Further analysis is ongoing.
We suggest follow up observation for this burst.
The points of contact for this burst is
Masanori Ohno ohno@astro.isas.jaxa.jp
The Fermi LAT is a pair conversion telescope designed to
cover the energy band from 20 MeV to greater than 300 GeV.
It is the product of an international collaboration between NASA and DOE in the U.S.
and many scientific institutions across France, Italy, Japan and Sweden.
This message can be cited.
- GCN Circular #9336
S. Guiriec, V. Connaughton and M. Briggs (UAH)
report on behalf of the Fermi GBM Team:
"At 00:22:59.97 UT on 2009 May 10, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090510 (trigger 263607781 / 090510016) which
was also detected by the Swift-BAT (Hoversten et al. 2009, GCN 9331) and
the Fermi-LAT (Ohno et al. 2009, GCN 9334).
The GBM position is consistent with those reported by Swift and the LAT.
The GBM triggered on a precursor lasting 30 ms followed 0.4 s later by an
intense and hard emission period of 0.5 s and a tail lasting
a further 0.5 s. The intense period has several narrow peaks and
its integrated spectrum is well fit by a Band function with
alpha =3D -0.80 +/- 0.03, beta =3D 2.6 +/- 0.3 and EPeak =3D 4.4 +/- 0.4 =
MeV.
The peak flux on a 64 ms timescale between 8 keV and 40 MeV was
measured 0.55 s after the trigger to be 80 ph.cm^-2.s^-1.
The 8 keV to 40 MeV fluence in the 0.512 s long period of intense emission
is (3.0 =B1 0.2) E-5 erg.cm^-2.
The spectral analysis results presented above are preliminary;
further analysis is on-going."
- GCN Circular #9337
T. N. Ukwatta (GWU) S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
E. A. Hoversten (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
(i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090510 (trigger #351588)
(Hoversten, et al., GCN Circ. 9331). The BAT ground-calculated position is
RA, Dec = 333.552, -26.598 deg, which is
RA(J2000) = 22h 14m 12.6s
Dec(J2000) = -26d 35' 51.1"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 16%.
The mask-weighted light curve shows a small precursor peak at ~T-0.54 sec
(width ~ 30 msec). Then the main peak starts at ~T-0.05 sec, peaks at T+0.04 sec
with a width of ~50 msec. Then come two smaller peaks at T+0.24 and T+0.32 sec,
each about 40 msec in width. At the 3-sigma level, there is the possibility
of low-level emission between T+110 sec to ~T+170 sec. T90 (15-350 keV)
is 0.3 +- 0.1 sec (estimated error including systematics).
The time-averaged spectrum from T+0.0 to T+0.4 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
0.98 +- 0.20. The fluence in the 15-150 keV band is 3.4 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.30 sec in the 15-150 keV band
is 9.7 +- 1.1 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/351588/BA/
- GCN Circular #9338
G. Olofsson, M. Ergon (Univ. Stockholm), D. Malesani, J.P.U. Fynbo
(DARK/NBI), P. Jakobsson (Univ. Iceland), N.R. Tanvir, K. Wiersema
(Univ. Leicester), A.J. Levan (Univ. Warwick), report on behalf of a
larger collaboration:
We observed the field of short Swift/Fermi GRB 090510 (Hoversten et al.,
GCN 9331; Ohno & Pelassa, GCN 9334; Guiriec et al., GCN 9336) with the
Nordic Optical Telescope equipped with ALFOSC. Observations were carried
out in twilight and at high airmass (~3).
The candidate afterglow (Marshall & Hoversten, GCN 9332) is clearly
detected in a stack of our images taken at a mean epoch May 10.215 UT
(4.7 hr after the GRB). Calibrating against closeby USNO stars (R1
magnitudes), we get R ~ 21.2. Comparing this value with the magnitude
reported by Marshall & Hoversten (GCN 9332) indicates fading, thus
confirming that this object is the afterglow of GRB 090510.
Astrometry of the field yields the following coordinates for the
afterglow (0.4" error):
RA(J2000) = 22:14:12.64
Dec(J2000) = -26:35:02.8
which is consistent with the UVOT position. We note the presence of a
fainter source ~1" East of the afterglow. A finding chart is posted at
the following URL:
http://www.astro.ku.dk/~malesani/GRB/090510/090510_finder.png
We acknowledge the observiers at the NOT for carrying out this difficult
observation.
- GCN Circular #9339
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1675 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090510, 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 = 333.55271, -26.58266 which is equivalent
to:
RA (J2000): 22h 14m 12.65s
Dec (J2000): -26d 34' 57.6"
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) and Evans
et al. (2009, arXiv:0812.3662).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
- GCN Circular #9340
D. Malesani (DARK/NBI) reports:
The coordinates of the afterglow reported in GCN 9338 (Olofsson et al.)
are wrong. The correct ones (referenced to USNO-B1 stars, 0.3" error) are:
RA(J2000) = 22:14:12.56
Dec(J2000) = -26:34:59.0
These coordinates are 0.7" away from the UVOT position (Marshall &
Hoversten, GCN 9332) and indeed consistent within their quoted error.
The object identified in the finding chart posted at
http://www.astro.ku.dk/~malesani/GRB/090510/090510_finder.png
is correctly the afterglow.
I thank Frank Marshall for pointing out the mistake, and regret for any
confusion that this may have created. No blame should go to the other
co-authors of GCN 9338.
- GCN Circular #9341
D. Grupe (PSU) and E. Hoversten (PSU) report on behalf of the Swift-
XRT team:
We have analysed XRT data for GRB090510 (Hoversten et al. GCN Circ.
9331) up to
25ks after the burst
beginning 94.1 s after the BAT trigger. The data comprise 200 s in
Windowed
Timing (WT) mode and 9.7 ks in Photon Counting (PC) mode.
The enhanced XRT position for this burst was given by Goad et al.
(GCN. Circ 9339).
The light curve can be modelled with a broken power-law decay with an
index of alpha=0.77+/-0.05, followed by a break at T+1470+/-160 s to
an alpha of 2.16 (+0.17, -0.14).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.57+/-0.08 with an
absorption column consistent with the Galactic
value of 1.66 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum
is consistent with this result.
If the light curve continues to decay with a power-law decay index of
2.16,
the count rate at T+24 hours will be 1.3e-4 counts/s, corresponding to
an
observed 0.3-10 keV flux of 6.1 x 10^-15 erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00351588.
This circular is an official product of the Swift-XRT team.
- GCN Circular #9342
N. P. M. Kuin (MSSL/UCL) and E.A. Hoversten (PSU) report on
behalf of the Swift UVOT team.
The Swift UltraViolet/Optical Telescope (UVOT) began observations of
the short hard burst GRB 090510 (Swift BAT trigger number 351588;
Hoversten et al. GCN Circ. 9331) on May 10, 2009, at 00:24:24 UT,
80 seconds after the BAT trigger with a settling exposure in the
UVOT v filter.
A new optical source was found by the UVOT (Marshall and Hoversten,
GCN Circ. 9332) for which we have a refined position (based on
matching the UVOT field sources to the USNO-B1 catalogue) of
RA, DEC = 333.55208, -26.58311, which is equivalent to:
RA = 22:14:12.5, DEC = -26:34:59.2, with an uncertainty of 1.5"
(90% confidence). The refined UVOT position is offset 1.6" from
the refined XRT position (Goad et al., GCN Circ. 9339) and is
consistent with the revised NOT position (Malesani, GCN Circ. 9340)
to within 0.2".
GRB 090510 is detected in all UVOT filters, except perhaps in b,
which implies that the redshift is less than about 1.5. The
emission is seen to rise to a peak around 600s after the trigger.
The initial magnitude observed in the UVOT filters are given below:
Filter Tstart(s) Tstop(s) Exposure(s) Magnitude
wh 97 247 147.4 19.63 +/- 0.17
wh 588 608 19.5 18.76 +/- 0.22
wh 1167 1526 58.3 19.16 +/- 0.20
v 80 1410 97.3 18.46 +/- 0.33
b 564 1502 97.2 >19.62 (2.2 sigma)
u 712 1477 323.6 19.05 +/- 0.17
uvw1 687 1452 75.9 18.61 +/- 0.27
uvm2 662 1434 93.7s 18.10 +/- 0.22
uvw2 614 1552 115.4s 18.31 +/- 0.18
The values quoted above are on the UVOT Photometric System
(Poole et al, 2008, MNRAS 383,627). They are not corrected for the
expected galactic reddening of E(B-V) = 0.020 in the direction of
the burst (Schlegel et al. 1998).
- GCN Circular #9343
F. Longo, E. Moretti, G. Barbiellini, E. Vallazza (INFN Trieste),
A. Giuliani (INAF/IASF Milan), S. Cutini, C. Pittori (ASDC) M.
Marisaldi, A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco,
C. Labanti, F. Fuschino, M. Galli (INAF/IASF Bologna),
A. Chen, S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF Milan),
Y. Evangelista, E. Del Monte, M. Feroci, I. Donnarumma, L. Pacciani, P.
Soffitta, E. Costa, F. Lazzarotto, I. Lapshov, M. Rapisarda(INAF/IASF
Rome), A. Pellizzoni, M. Pilia (INAF/OA Cagliari), S. Vercellone
(INAF/IASF Palermo),
M. Tavani, G. Pucella, F. D'Ammando, V.Vittorini, A. Argan, A. Trois,
G. Piano, S. Sabatini (INAF/IASF Rome), P. Picozza, A. Morselli (INFN
Roma-2), M. Prest (Universita` dell'Insubria), P. Lipari, D. Zanello
(INFN Roma-1), A. Rappoldi, P. Cattaneo (INFN Pavia) and P. Giommi,
P. Santolamazza,
F. Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team,
report:
AGILE detected the remarkable short GRB 090510 (Hoversten et al. GCN
#9331, Ohno et al. GCN #9334) at approximately 61 degrees off-axis.
An analysis of AGILE-GRID data shows an above 5-sigma detection of
gamma-ray emission above 100 MeV. The gamma-ray lightcurve above 100 MeV
shows emission during both the prompt phase and during a "delayed" phase.
Also the Mini-Calorimeter detected a very significant and structured
event lasting ~200 msec with emission well above 3 MeV.
The burst triggered also SuperAGILE, although outside the field of view.
This is the first short GRB with emission above 100 MeV detected by AGILE.
- GCN Circular #9344
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:
The short hard GRB 090510 (Swift-BAT trigger #351588: Hoversten et al.,
GCN 9331, Ukwatta et al., GCN 9337; Fermi-LAT trigger 263607783 /
090510016: Ohno & Pelassa, GCN 9334) triggered Konus-Wind at T0=1381.547
s UT (00:23:01.547).
The burst light curve shows a multipeaked structure with a duration of
~0.4 s
As observed by Konus-Wind the burst
had a fluence of (2.42 +/- 0.37)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+0.002 s
of (2.27 +/- 0.63)x10^-4 erg/cm2/s
(both in the 20 keV - 15 MeV energy range).
The spectrum of the most intense part
(from T0 to T0+0.192 s; it comprises ~75% of the total counts)
is well fitted (in the 20 keV - 15 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = 0.11(-0.43, +0.48),
the high energy photon index beta = -1.61(-0.34, +0.15),
the peak energy E0 = 552(-249, +448) keV (chi2 = 28.6/31 dof).
Since beta > -2 we can establish only the lower limit on the peak energy
in the EF(E) spectrum: Ep > 912 keV.
The emission is clearly seen up to the end of the Konus-Wind energy
range at 15 MeV.
All the quoted errors are at the 90% confidence level.
We note that since beta > -2 the bolometric fluence might be
substantially higher than the given value.
The Konus-Wind light curve of this GRB is available
at
http://www.ioffe.ru/LEA/GRBs/GRB090510_T01381/
- GCN Circular #9345
V. Pal'shin on behalf of the Konus-Wind team, report:
"...the peak energy E0 = 552(-249, +448) keV (chi2 = 28.6/31 dof)."
in GCN 9344
should be read as:
"...the e-folding energy E0 = 552(-249, +448) keV (chi2 = 28.6/31 dof)."
- GCN Circular #9350
N. Omodei (INFN Pisa), J. Granot (University of Hertfordshire),
P. Meszaros (PSU), J. McEnery (GSFC), F. Piron (LPTA), S. Razzaque (NRL)
H. Tajima (SLAC), V. Vasileiou (GSFC/UMBC), D. Williams (UCSC),
report on behalf of the Fermi LAT Collaboration.
A follow-up analysis of the short bright Fermi GRB 090510 (Ohno et al.,
GCN 9334, Guiriec et al., GCN 9336) has been performed by the Fermi-LAT
team.
Fermi LAT has detected more than 50 events above 100 MeV (>10 above 1
GeV) during the first second and more than 150 events above 100 MeV (>20
above 1 GeV) in the first minute after the GBM trigger.
All these events are positionally consistent (within the 95% containment
radius of the LAT point spread function) with the position reported by
Swift (Goad et al. GCN 9339). They indicate extended emission above GeV
energies, making this burst an absolute priority for follow-up searches,
especially a redshift determination.
The points of contact for this burst is:
Masanori Ohno ohno@astro.isas.jaxa.jp
The Fermi LAT is a pair conversion telescope designed to
cover the energy band from 20 MeV to greater than 300 GeV.
It is the product of an international collaboration between NASA and DOE
in the U.S. and many scientific institutions across France, Italy, Japan
and Sweden.
- GCN Circular #9351
N. P. M. Kuin (MSSL/UCL), S. Oates (MSSL/UCL), M. De Pasquale (MSL/UCL),
E.A. Hoversten (PSU), and F. Marshall (GSFC) report on behalf of the
Swift UVOT team.
The Swift UltraViolet/Optical Telescope (UVOT) continued observations of
the short hard burst GRB 090510 (Swift BAT trigger number 351588;
Hoversten et al. GCN Circ. 9331) today. The summed image in the white
filter taken between 92.7ks and 127.6 ks shows that the source has faded
from the initial magnitude of wh = 18.76 mag at T+800 and is now possibly
detected at 3.3 sigma at a magnitude of 22.9+/-0.3. Observations between
T+2000s and T+100ks show a decay index of about 1. There are also two
nearby sources at the 6 sigma level detectable, which we consider to be
possible hosts of GRB 090510.
The first, nearest, candidate is at position RA, DEC = 333.55220, -26.584525
(22h 14m 12.53s, -26d 35m 04.29s (J2000)), with a diameter of 2.3", and the
second, more extended, candidate is found at position RA, DEC =
333.54963, -26.582294 (22h 14m 11.91s, -26d 34m 56.26s (J2000)), is more
elongated with a diameter of about 3.1". The estimated positional accuracy
is 0.7" for both sources. Both sources have a wh magnitude of 21.61 +/- 0.17.
We encourage follow-up observations.
We would like to make a correction: The UVOT positional error on GRB 090510
quoted in GCN 9342 was too large. The correct uncertainty in the GRB position
was 0.61" (90% confidence radius).
- GCN Circular #9352
F. Olivares (MPE Garching), S. Klose (Tautenburg), T. Kruehler, J. Greiner
(both MPE Garching) report on behalf of the GROND team:
GROND, mounted at the 2.2m on La Silla, observed the field of GRB 090510,
detected by Swift (Hoversten et al., GCN 9331), Fermi GBM (Guiriec et al.,
GCN 9336) and LAT (Ohno & Pelassa, GCN #9334), AGILE (Longo et al., GCN
9343) and Konus-Wind (Golenetskii et al., GCN 9344), in g'r'i'z'JHK
starting at 6:34 UT on 10 May 2009.
We detect the afterglow reported by Marshall & Hoversten (GCN #9332) and
Olofsson et al. (GCN #9338) in the optical bands. At a midtime of 9.0 h
after the burst, we measure the following AB magnitudes of the afterglow
and upper limits in stacked images
g' = 23.5 +/- 0.3
r' = 23.0 +/- 0.1
i' = 22.8 +/- 0.1
z' = 22.6 +/- 0.1
J > 21.8
H > 21.4
K > 20.7
calibrated against the GROND zeropoints and 2MASS field stars. We caution
that the photometry might be contaminated by the nearby source mentioned by
Olofsson et al. (GCN #9338).
Together with the magnitude reported by NOT (Olofsson et al. GCN #9338),
this implies a rapid early fading with an index of ~2 during this epoch,
which is compatible to the X-ray afterglow at a similar time interval
(Grupe & Hoversten, GCN #9341). A late flattening of the optical light
curve is then indicated by the UVOT detection (Kuin et al. #GCN 9351).
- GCN Circular #9353
Arne Rau (MPE Garching), Sheila McBreen (UCD/MPE Garching), Thomas
Kruehler, and Jochen Greiner (both MPE Garching) report:
We present follow-up optical spectroscopy of the short Swift/Fermi GRB
090510 (Hoversten et al., GCN 9331; Ohno & Pelassa, GCN 9334; Guiriec
et al., GCN 9336) using VLT/FORS2 (PI McBreen). Observations of the
optical source consistent with position of the afterglow (Marshall &
Hoversten, GCN 9332; Olofsson et al., GCN 9338; Olivares et al., GCN
9352) started on May 12 08:17UT. A total of three 30min exposures
with the 300I grism were obtained, covering an approximate wavelength
range of 6000-10000 Angstroms.
Preliminary analysis of the spectra reveals two emission lines at 7093
and 9250 Angstroms, which we identify as [OII] and Hbeta at a common
redshift of z=0.903 +/- 0.003. Furthermore, there are indications of a
spectral break in the continuum around 7600 Angstroms, suggesting a
possible 4000A break at the same redshift.
The detection of emission lines and the possible 4000A break suggest
the dominance of the underlying host galaxy over the afterglow at the
time of our observations. It also confirms that host galaxies of short
GRBs are not all old and dead ellipticals but instead drawn from the
underlying field galaxy distribution (e.g., Berger 2009, ApJ, 690,
231).
In the acquisition image the center of the host is 0.7" offset with
respect to the NOT refined afterglow position, which corresponds to 5.5
kpc at z=0.903.
At a redshift of z=0.903, the isotropic equivalent energy of the burst
is 3.8E52 erg in the 1 keV - 10 MeV rest frame (using the Fermi/GBM
spectral parameters of Guiriec et al., GCN 9336). The peak energy of
the best fit GBM Band function model is 8.4 +/- 0.8 MeV in the rest
frame.
We acknowledge excellent support from the ESO staff, in particular
F. Selman and I. Condor.
- GCN Circular #9354
D. A. Frail (NRAO) and P. Chandra (RMC) report on behalf of a
larger collaboration:
"We have used the Very Large Array (VLA) to image a field toward the
short, bright Fermi-LAT burst GRB 090510 (GCN # 9350, 9334). The VLA
observed at a frequency of 8.46 GHz on three epochs, May 11.48, May
12.48 and May 13.52 UT. There is no radio source detected at the
position of the optical afterglow (GCN #9340). Adding the data
together for all three epochs, the 3-sigma limit is 84 uJy. No further
observations are planned.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
- GCN Circular #9355
N. Ohmori, K. Noda, E. Sonoda, M. Yamauchi, K. Kono, H. Hayashi,
A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa (Hiroshima U.),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
on behalf of the Suzaku WAM team, report:
The short hard GRB 090510 detected by the Fermi-LAT (Swift/BAT trigger
#351588; Hoversten et al., GCN 9331,Fermi-LAT trigger #263607783;
Ohno et al., GCN 9334)
triggered the Suzaku Wide-band All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 00:23:00 UT (=T0).
The observed light curve shows a multi-peaked structure starting at T0-0.1s,
ending at T0+0.9s with a duration (T90) of about 0.33 seconds.
The emissions was clearly detected at least up to 5 MeV.
However, since the incident angle of this burst to the WAM is off-axis, we
cannot perform a reliable spectral analysis at this moment.
We are now improving our detector response from such an off-axis direction.
The light curves for this burst are available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
- GCN Report 218.1
GCN_Report 218.1 has been posted:
http://gcn.gsfc.nasa.gov/reports/report_218_1.pdf
by E.A. Hoversten
at PSU
titled: "Final Swift Results on GRB 090510"
-
Press
story in New York Times on Nature article.
- 1002.0228 from 2 Feb 10
Masanori Ohno et al.: Fermi-LAT observations of GRBs with weak LAT emission
We present the analysis results of three Gamma-Ray Bursts (GRBs) detected by the Gamma-ray Burst Monitor (GBM) and the Large Area Telescope
(LAT) onboard Fermi: the two long GRB 080825C and GRB 090217, and the first short burst with GeV photons GRB 081024B. The emission from GRB
081024B observed by the LAT above 100 MeV is delayed with respect to the GBM trigger, and significantly extends after the low-energy episode.
Some hints for spectral hardening was observed in this burst as well as in GRB 080825C, possibly related to a separate and harder component
showing up at late times. Conversely, GRB 090217 does not exhibit any noticeable feature. Together with the other bright LAT detected bursts
(e.g. GRB 080916C and GRB 090510), these observations help to classify the GRB properties and give new insight on the acceleration mechanisms
responsible for their emission at the highest energies.
- 1002.0349 from 3 Feb 10
Vlasios Vasileiou: Constraining Lorentz Invariance Violation with Fermi
A cornerstone of special relativity is Lorentz Invariance, the postulate that all observers measure exactly the same photon speeds
independently on the photon energies. However, a hypothesized structure of spacetime may alter this conclusion at ultra-small length scales, a
possibility allowed in many of the Quantum-Gravity (QG) formalisms currently investigated. A generalized uncertainty principle suggests that
such effects might occur for photon energies approaching the Planck energy, $E_{Planck}=M_{Planck} c^2 \simeq 1.22\times10^{19} GeV$. Even
though all photons yet detected have energies $E_{ph}< 1002.2863 from 16 Feb 10
V. Pelassa et al.: Fermi and Swift observations of the bright short GRB 090510
The bright short-hard GRB 090510 was observed by both Swift and Fermi telescopes. The study of the prompt emission by Fermi revealed an
additional high-energy spectral component, the largest lower limit ever on the bulk Lorentz factor in a short GRB jet, and brought the most
stringent constraint ever on linear Lorentz invariance violation models. The fast repoint and follow-up by both telescopes allowed the first
multiwavelength study of a GRB afterglow from optical range to several GeV. This long-lived emission has been studied in the framework of the
internal shock and external shock models.
- 1002.3377 from 19 Feb 10
G. Ghisellini et al.: Fermi/LAT Gamma Ray Burst emission models and jet properties
The GeV emission of Gamma Ray Bursts, first detected by EGRET in an handful of bursts, is now an established property of roughly the 10% of all
bursts, thanks to the Fermi/LAT observations. GRB 090510, a short burst, is particularly interesting because the good timing allows to derive a
severe limit to theories of quantum gravity. With the dozen bursts detected in the 0.1-30 GeV band so far, we start to see some common
properties: (i) the duration is often longer than the duration of the softer emission detected by the Gamma Burst Monitor (GBM) onboard Fermi;
(ii) the spectrum is consistent with F(v)~v^{-1} with no strong spectral evolution; (iii) for the brightest bursts, the flux detected by the
LAT decays as a power law with a typical slope: t^{-1.5}; iv) the peak energy of the GBM emission exceeds 500 keV (rest frame). These
properties suggest a similar process for the origin of the GeV flux. We propose that it is afterglow synchrotron emission shortly following the
start of the prompt phase. The steep decay slope suggests that the fireball emits in the radiative regime, i.e. all dissipated energy is
radiated away. The large peak energy of the GBM flux suggests that electron-positron pairs might play a crucial role. The rapid onset, but with
some delay, of the GeV flux with respect to the GBM one suggests that the bulk Lorentz factor Gamma of these bursts is of the order of 1000.
Therefore the relatively small fraction of bursts detected at high energies might correspond to the fraction of bursts having the largest
Gamma. If the emission occurs in the radiative regime we can start to understand why the observed X-ray and optical afterglow energetics are
much smaller than the energetics emitted during the prompt phase.
- 1003.3885 from 23 Mar 10
S. McBreen et al.: Optical and near-infrared follow-up observations of four Fermi/LAT GRBs : Redshifts, afterglows, energetics and host galaxies
Fermi can measure the spectral properties of gamma-ray bursts over a very large energy range and is opening a new window on the prompt emission
of these energetic events. Localizations by the instruments on Fermi in combination with follow-up by Swift provide accurate positions for
observations at longer wavelengths leading to the determination of redshifts, the true energy budget, host galaxy properties and facilitate
comparison with pre-Fermi bursts. Multi-wavelength follow-up observations were performed on the afterglows of four bursts with high energy
emission detected by Fermi/LAT : GRB090323, GRB090328, GRB090510 and GRB090902B. They were obtained in the optical/near-infrared bands with
GROND mounted at the MPG/ESO 2.2m telescope and additionally of GRB090323 in the optical with the 2 m telescope in Tautenburg, Germany. Three
of the events are classified as long bursts while GRB090510 is a well localized short GRB with GeV emission. In addition, host galaxies were
detected for three of the four bursts. Spectroscopic follow-up was initiated with the VLT for GRB090328 and GRB090510. The afterglow
observations in 7 bands are presented for all bursts and their host galaxies are investigated. Knowledge of the distance and the local dust
extinction enables comparison of the afterglows of LAT-detected GRBs with the general sample. The spectroscopic redshifts of GRB090328 and
GRB090510 were determined to be z=0.7354+/-0.0003 and z=0.903 +/- 0.001 and dust corrected star-formation rates of 4.8 Mdot yr^-1 and 0.60
M_dot yr^-1 were derived for their host galaxies, respectively. The afterglows of long bursts exhibit power-law decay indices alpha from less
than 1 to ~2.3 and spectral indices (beta) values from 0.65 to ~1.2 which are fairly standard for GRB afterglows. Constraints are placed on the
jet half opening angles of less than 2.1 deg to greater than 6.4 deg which allows limits to be placed on the beaming corrected energies. These
range from less than 5x10^50 erg to the one of the highest values ever recorded, greater than 2.2x10^52 erg for GRB090902B, and are not
consistent with a standard candle. The extremely energetic long Fermi bursts have optical afterglows which lie in the top half of the
brightness distribution of all optical afterglows detected in the Swift era or even in the top 5% if incompleteness is considered. The
properties of the host galaxies of these LAT detected bursts in terms of extinction, star formation rates and masses do not appear to differ
from previous samples.
- 1005.1051 from 7 May 10
Ano Neamus: Can the forward-shock model account for the multiwavelength emission of GRB afterglow 090510 ?
GRB 090510 is the first burst whose afterglow emission above 100 MeV was measured by Fermi over two decades in time. Owing to its power-law
temporal decay and power-law spectrum, it seems likely that the high-energy emission is from the forward-shock energizing the ambient medium
(the standard blast-wave model for GRB afterglows), the GeV flux and its decay rate being consistent with that model's expectations. However,
the synchrotron emission from a collimated outflow (the standard jet model) has difficulties in accounting for the lower-energy afterglow
emission, where a simultaneous break occurs in the optical and X-ray light-curves at 2 ks, but with the optical flux decay (before and after
the break) being much slower than in the X-rays (at same time). The measured X-ray and GeV fluxes are incompatible with the higher-energy
afterglow emission being from same spectral component as the lower-energy afterglow emission, which suggests a synchrotron self-Compton model
for this afterglow. Cessation of energy injection in the blast-wave can account for the optical and X-ray light-curves provided that the
ambient medium has a wind-like n propto r^{-2} density. The latter is incompatible with this short-GRB originating from the merger of two
compact stars.
- 1005.2141 from 13 May 10
The Fermi LAT et al.: Fermi Observations of GRB 090510: A Short Hard Gamma-Ray Burst with an Additional, Hard Power-Law Component from 10 keV to GeV Energies
We present detailed observations of the bright short-hard gamma-ray burst GRB 090510 made with the Gamma-ray Burst Monitor (GBM) and Large Area
Telescope (LAT) on board the Fermi observatory. GRB 090510 is the first burst detected by the LAT that shows strong evidence for a deviation
from a Band spectral fitting function during the prompt emission phase. The time-integrated spectrum is fit by the sum of a Band function with
$\Epeak = 3.9\pm 0.3$\,MeV, which is the highest yet measured, and a hard power-law component with photon index $-1.62\pm 0.03$ that dominates
the emission below $\approx$\,20\,keV and above $\approx$\,100\,MeV. The onset of the high-energy spectral component appears to be delayed by
$\sim$\,0.1\,s with respect to the onset of a component well fit with a single Band function. A faint GBM pulse and a LAT photon are detected
0.5\,s before the main pulse. During the prompt phase, the LAT detected a photon with energy $30.5^{+5.8}_{-2.6}$ GeV, the highest ever
measured from a short GRB. Observation of this photon sets a minimum bulk outflow Lorentz factor, $\Gamma\ga$\,1200, using simple
$\gamma\gamma$ opacity arguments for this GRB at redshift $z = 0.903$ and a variability time scale on the order of tens of ms for the
$\approx$\,100\,keV--few MeV flux. Stricter high confidence estimates imply $\Gamma \ga 1000$ and still require that the outflows powering
short GRBs are at least as highly relativistic as those of long duration GRBs. Implications of the temporal behavior and power-law shape of the
additional component on synchrotron/synchrotron self-Compton (SSC), external-shock synchrotron, and hadronic models are considered.
- 1009.1432 from 9 Sep 10
Hao-Ning He et al.: On the High Energy Emission of the Short GRB 090510
Long-lived high-energy (>100 MeV) emission, a common feature of most Fermi-LAT detected Gamma-ray burst, is detected up to ~10^2 s in the short
GRB 090510. We study the origin of this long-lived high-energy emission of GRB 090510, using broad-band observations including X-ray and
optical data. We confirm that the late > 100 MeV, X-ray and optical emission can be naturally explained via synchrotron emission from an
adiabatic forward shock propagating in a homogeneous ambient medium with low number density. The Klein-Nishina effects are found to be
significant, and effects due to jet spreading and magnetic field amplification in the shock appear to be required. Under the constraints from
the low-energy observations, the adiabatic forward shock synchrotron emission is consistent with the later-time (t > 2 s) high-energy emission,
but falls below the early-time (t<2 s) high energy emission. Thus we argue that an extra high energy component is needed at early times, which
accounts for the initial steep decay of the light curve. We consider several possible origins for the extra component, most of which can be
excluded. Based on the high initial temporal variability and the coincident emerging bumps in the LAT and BAT light curves at t~1-3 s, we
suggest that the duration of the prompt emission is T~2 s. Thus, we attribute the early part of the high-energy emission (t<2 s) to the prompt
component, and the long-lived high energy emission (t>2 s) to the adiabatic forward shock synchrotron afterglow radiation. This avoids the
requirement for an extremely high initial Lorentz factor.
- 1108.6034 from 31 Aug 11
HAWC collaboration: A. U. Abeysekara et al.: On the sensitivity of the HAWC observatory to gamma-ray bursts
We present the sensitivity of HAWC to Gamma Ray Bursts (GRBs). HAWC is a very high-energy gamma-ray observatory currently under construction in
Mexico at an altitude of 4100 m. It will observe atmospheric air showers via the water Cherenkov method. HAWC will consist of 300 large water
tanks instrumented with 4 photomultipliers each. HAWC has two data acquisition (DAQ) systems. The main DAQ system reads out coincident signals
in the tanks and reconstructs the direction and energy of individual atmospheric showers. The scaler DAQ counts the hits in each
photomultiplier tube (PMT) in the detector and searches for a statistical excess over the noise of all PMTs. We show that HAWC has a realistic
opportunity to observe the high-energy power law components of GRBs that extend at least up to 30 GeV, as it has been observed by Fermi LAT.
The two DAQ systems have an energy threshold that is low enough to observe events similar to GRB 090510 and GRB 090902b with the
characteristics observed by Fermi LAT. HAWC will provide information about the high-energy spectra of GRBs which in turn will lead to
understanding about e-pair attenuation in GRB jets, extragalactic background light absorption, as well as establishing the highest energy to
which GRBs accelerate particles.
- 1109.5191 from 27 Sep 11
Robert J. Nemiroff et al.: Limiting properties of light and the universe with high energy photons from Fermi-detected Gamma Ray Bursts
An analysis of four Fermi-detected gamma-ray bursts (GRBs) is given that sets upper limits on the energy dependence of the speed and dispersion
of light across the universe. The analysis focuses on photons recorded above 1 GeV for Fermi detected GRB 080916C, GRB 090510A, GRB 090902B,
and GRB 090926A. Upper limits on time scales for statistically significant bunching of photon arrival times were found and cataloged. In
particular, the most stringent limit was found for GRB 090510A at redshift $z \gtrsim 0.897$ for which $\Delta t < 0.00136$ sec, a limit driven
by three separate photon bunchings. These photons occurred among the first seven super-GeV photons recorded for GRB 090510A and contain one
pair with an energy difference of $\Delta E \gtrsim 23.5$ GeV. The next most limiting burst was GRB 090902B at a redshift of $z \gtrsim 1.822$
for which $\Delta t < 0.161$, a limit driven by several groups of photons, one pair of which had an energy difference $\Delta E \gtrsim$ 1.56
GeV. Resulting limits on the differential speed of light and Lorentz invariance were found for all of these GRBs independently. The strongest
limit was for GRB 090510A with $\Delta c / c < 6.09$ x $10^{-21}$. Given generic dispersion relations across the universe where the time delay
is proportional to the photon energy to the first or second power, the most stringent limits on the dispersion strengths were $k_1 <$ 1.38 x
$10^{-5}$ sec Gpc$^{-1}$ GeV$^{-1}$ and $k_2 <$ 3.04 x $10^{-7}$ sec Gpc$^{-1}$ GeV$^{-2}$ respectively. Such upper limits result in upper
bounds on dispersive effects created, for example, by dark energy, dark matter or the spacetime foam of quantum gravity. Relating these
dispersion constraints to loop quantum gravity energy scales specifically results in limits of $M_1 c^2 >$ 7.43 x $10^{21}$ GeV and $M_2 c^2 >$
7.13 x $10^{11}$ GeV respectively.
- 1206.4187 from 20 Jun 12
M. Lemoine: Synchrotron signature of a relativistic blast wave with decaying microturbulence
Microphysics of weakly magnetized relativistic collisionless shock waves, corroborated by recent high performance numerical simulations,
indicate the presence of a microturbulent layer of large magnetic field strength behind the shock front, which must decay beyond some hundreds
of skin depths. The present paper discusses the dynamics of such microturbulence, borrowing from these same numerical simulations, and
calculates the synchrotron signature of a powerlaw of shock accelerated particles. The decaying microturbulent layer is found to leave distinct
signatures in the spectro-temporal evolution of the spectrum $F_\nu \propto t^{-\alpha}\nu^{-\beta}$ of a decelerating blast wave, which are
potentially visible in early multi-wavelength follow-up observations of gamma-ray bursts. This paper also discusses the influence of the
evolving microturbulence on the acceleration process, with particular emphasis on the maximal energy of synchrotron afterglow photons, which
falls in the GeV range for standard gamma-ray burst parameters. Finally, this paper argues that the evolving microturbulence plays a key role
in shaping the spectra of recently observed gamma-ray bursts with extended GeV emission, such as GRB090510.
- 1212.4418 from 19 Dec 12
N. Fraija et al.: Long and short high energy components presented in GRBs
We present a leptonic model on the external shock framework to describe the long- and short- lasting GeV component of some GRBs. This model was
already applied successfully to GRB 090926A, and we extend it to describe the high-energy emission of GRB 090902B and GRB 090510. We argue that
the high-energy emission consists of two components, one at MeV energies with a duration of a few seconds during the prompt phase, and a second
GeV component lasting hundred of seconds after the prompt phase. The short high-energy component can be described as SSC emission from a
reverse shock and the longer component arises from SSC emission of the forward shock. The main assumption of our model is that the jet is
magnetized and evolves in the thick-shell case. The calculated fluxes and break energies are all consistent with the observed values.
- 1303.1564 from 8 Mar 13
D. Zaborov et al.: The HAWC observatory as a GRB detector
The High Altitude Water Cherenkov Observatory (HAWC) is an air shower array currently under construction in Mexico at an altitude of 4100 m.
HAWC will consist of 300 large water tanks covering an area of about 22000 square meters and instrumented with 4 photomultipliers each. The
experimental design allows for highly efficient detection of photon-induced air showers in the TeV and sub-TeV range and gamma-hadron
separation. We show that HAWC has a reasonable chance to observe the high-energy power law components of GRBs that extend to 50 GeV. In
particular, HAWC will be capable of observing events similar to GRB 090510 and GRB 090902B. The observations (or non-observations) of GRBs by
HAWC will provide information on the high-energy spectra of GRBs. An engineering array consisting of 6 water tanks was operated at the HAWC
site since September 2011, collecting 3 months of data. An upper limit on high energy emission from GRB 111016B is derived from these data.
- 1306.3467 from 17 Jun 13
M. Muccino et al.: GRB 090510: a disguised short GRB with the highest Lorentz factor and circumburst medium
GRB 090510, observed both by Fermi and AGILE satellites, is the first bright short-hard Gamma-Ray Burst (GRB) with an emission from the keV up
to the GeV energy range. Within the Fireshell model, we interpret the faint precursor in the light curve as the emission at the transparency of
the expanding e+e- plasma: the Proper-GRB (P-GRB). From the observed isotropic energy we assume a total energy Ee+e-=(1.10+-0.06)*10^53 erg and
derive a Baryon load B=(1.45+-0.28)*10^(-3) and a Lorentz factor at transparency Gamma=(6.7+-1.6)*10^2. The main emission 0.4 s after the
initial spike is interpreted as the extended afterglow, due to the interaction of the ultrarelativistic baryons with the CircumBurst Medium
(CBM). Using the condition of fully radiative regime, we infer a CBM average spherically symmetric density of nCBM=(1.85+-0.14)10^3 cm^(-3),
one of the highest found in the Fireshell model. The value of the filling factor, 1.5*10^(-10) 1306.4822 from 21 Jun 13
Hirotaka Ito et al.: Photospheric emission from stratified jets
We explore photospheric emissions from stratified two-component jets, wherein a highly relativistic spine outflow is surrounded by a wider and
less relativistic sheath outflow. The propagation of thermal photons which are injected in regions of high optical depth is solved until they
escape at the photosphere. Due to the presence of shear in velocity (Lorentz factor) at the boundary of the spine and sheath region, fraction
of the injected photons are accelerated via a Fermi-like acceleration mechanism such that a high energy power-law tail is formed in the
resultant spectrum. We show, in particular, that if a velocity shear with a considerable variance in the bulk Lorentz factor is present, the
high energy part of observed Gamma-ray Bursts (GRBs) photon spectrum can be explained by this photon acceleration mechanism. We also show that
the accelerated photons may also account for the origin of the extra hard power-law component above the bump of the thermal-like peak seen in
some peculiar burst (e.g., GRB 090510, 090902B, 090926A). It is demonstrated that time-integrated spectra can also reproduce the low energy
spectrum of GRBs consistently due to a multi-temperature effect when time evolution of the outflow is considered. Finally, we show that the
empirical Ep-Lp relation can be explained by the difference in the outflow properties of individual sources.
- 1307.5212 from 22 Jul 13
Floyd W. Stecker: Tests of Lorentz Invariance Using High Energy Astrophysics Observations
High-energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance, such as may be
related to the structure of space-time near the Planck scale. I discuss the possible signatures of Lorentz invariance violation that can be
manifested by observing the spectra, polarization, and timing of gamma-rays from active galactic nuclei and gamma-ray bursts. Other sensitive
tests are provided by observations of the spectra of ultrahigh-energy cosmic rays and very high-energy neutrinos. I also discuss a new
time-of-flight analysis of observations of GRB 090510 by the Fermi gamma-ray Space Telescope. These results, based on high-energy astrophysical
observations, have fundamental implications for space-time physics and quantum gravity models.
- 1503.08794 from 31 Mar 15
Jakub Mielczarek: From Causal Dynamical Triangulations To Astronomical Observations
This essay discusses phenomenological aspects of the diffusion time dependence of the spectral dimension predicted by the Causal Dynamical
Triangulations (CDT) approach to quantum gravity. The deformed form of the dispersion relation for the fields defined on the CDT space-time is
reconstructed. Using the \emph{Fermi} satellite observations of the GRB 090510 source we find that the energy scale of the dimensional
reduction is $E_* > 6.7 \cdot 10^{10}$ GeV at (95 $\%$ CL).
By applying the deformed dispersion relation to the cosmological perturbations it is shown that, for a scenario when the primordial
perturbations are formed in the UV region, the scalar power spectrum $\mathcal{P}_S \propto k^{n_S-1}$ where $n_S-1\approx \frac{3r(d_{\rm
UV}-2)}{r+48(d_{\rm UV}-3)}$. Here, $d_{\rm UV} \approx 2$ is obtained from the CDT value of the spectral dimension in the UV limit and $r$ is
the tensor-to-scalar ratio. We find that, the predicted deviation from the scale-invariance ($n_S=1$) is in contradiction with the up to date
\emph{Planck} and \emph{BICEP2} results.
Replacements for Tue, 31 Mar 15
- 1504.06369 from 27 Apr 15
Romain Hascoët et al.: Measuring Ambient Densities and Lorentz Factors of Gamma-Ray Bursts from GeV and Optical Observations
Fermi satellite discovered that cosmological gamma-ray bursts (GRBs) are accompanied by long GeV flashes. In two GRBs, an optical counterpart
of the GeV flash has been detected. Recent work suggests that the GeV+optical flash is emitted by the external blast wave from the explosion in
a medium loaded with copious $e^\pm$ pairs. The full light curve of the flash is predicted by a first-principle radiative transfer simulation
and can be tested against observations. Here we examine a sample of 7 bursts with best GeV+optical data and test the model. We find that the
observed light curves are in agreement with the theoretical predictions and allow us to measure three parameters for each burst: the Lorentz
factor of the explosion, its isotropic kinetic energy, and the external density. With one possible exception of GRB 090510 (which is the only
short burst in the sample) the ambient medium is consistent with a wind from a Wolf-Rayet progenitor. The wind density parameter $A=\rho r^2$
varies in the sample around $10^{11}$g/cm. The initial Lorentz factor of the blast wave varies from 200 to 540 and correlates with the burst
luminosity. Radiative efficiency of the prompt emission in the sample is between 0.1 and 0.8. For the two bursts with detected optical flash,
GRB 120711A and GRB 130427A, we also estimate the magnetization of the external blast wave. Remarkably, the model reproduces the entire optical
light curve of GRB 120711A (with its sharp peak, fast decay, plateau, and break) as well as the GeV data. The spectrum of GeV flashes is
predicted to extend above 0.1 TeV, where they can be detected by ground-based Cherenkov telescopes.
- 1603.07568 from 25 Mar 16
Jun-Jie Wei et al.: Limits on the Neutrino Velocity, Lorentz Invariance, and the Equivalence Principle with TeV neutrinos from Gamma-Ray Bursts
Five TeV neutrino events weakly correlated with five gamma-ray bursts (GRBs) were detected recently by IceCube. If the correlation is real, the
observed time delays between the TeV neutrinos and gamma-ray photons from GRBs provide attractive candidates for testing fundamental physics
with high accuracy. Based on the associations between the TeV neutrinos and GRBs, we show that the limiting velocity of neutrinos is equal to
that of photons to an accuracy of $\sim2.5\times10^{-18}$, which is about $10^{7}$ times better than the constraint obtained with neutrino from
blazar flares. In addition, we set the most stringent limits up to date on the energy scales of quantum gravity for both the linear and
quadratic violations of Lorentz invariance, namely $E_{\rm QG, 1}>1.5\times10^{21}$ GeV and $E_{\rm QG, 2}>4.2\times10^{12}$ GeV, which
represent an improvement of one order of magnitude over the results previously obtained by the GeV photons of GRB 090510 and the PeV neutrino
from blazar flares. Assuming that the Shapiro time delay is caused by the gravitational potential of the Laniakea supercluster of galaxies, we
also place the tightest limit to date on the Einstein Equivalence Principle through the relative differential variations of the parameterized
post-Newtonian parameter $\gamma$ values for two different species of particles (i.e., neutrinos and photons), yielding $\Delta\gamma \sim
10^{-13}$.
- 1607.02400 from 11 Jul 16
M. Enderli et al.: GRB 090510: a genuine short-GRB from a binary neutron star coalescing into a Kerr-Newman black hole
In a new classification of merging binary neutron stars (NSs) we separate short gamma-ray bursts (GRBs) in two sub-classes. The ones with
$E_{\rm iso}\lesssim10^{52}$ erg coalesce to form a massive NS and are indicated as short gamma-ray flashes (S-GRFs). The hardest, with $E_{\rm
iso}\gtrsim10^{52}$ erg, coalesce to form a black hole (BH) and are indicated as genuine short-GRBs (S-GRBs). Within the fireshell model,
S-GRBs exhibit three different components: the P-GRB emission, observed at the transparency of a self-accelerating baryon-$e^+e^-$ plasma; the
prompt emission, originating from the interaction of the accelerated baryons with the circumburst medium; the high-energy (GeV) emission,
observed after the P-GRB and indicating the formation of a BH. GRB 090510 gives the first evidence for the formation of a Kerr-Newman BH. Its
P-GRB spectrum can be fitted by a convolution of thermal spectra whose origin can be traced back to an axially symmetric dyadotorus. A large
value of the angular momentum of the newborn BH is consistent with the large energetics of this S-GRB, which reach in the 1-10000 keV range
$E_{\rm iso}=(3.95\pm0.21)\times10^{52}$ erg and in the 0.1-100 GeV range $E_{\rm LAT}=(5.78\pm0.60)\times10^{52}$ erg, the most energetic GeV
emission ever observed in S-GRBs. The theoretical redshift $z_{\rm th}=0.75\pm0.17$ that we derive from the fireshell theory is consistent with
the spectroscopic measurement $z=0.903\pm0.003$, showing the self-consistency of the theoretical approach. All S-GRBs exhibit GeV emission,
when inside the Fermi-LAT field of view, unlike S-GRFs, which never evidence it. The GeV emission appears to be the discriminant for the
formation of a BH in GRBs, confirmed by their observed overall energetics.
- 1608.01420 from 5 Aug 16
Nissim Fraija et al.: Modeling the early afterglow in the short and hard GRB 090510
The bright, short and hard GRB 090510 was detected by all instruments aboard Fermi and Swift satellites. The multiwavelength observations of
this burst presented similar features with the Fermi-LAT-detected gamma-ray bursts. In the framework of the external shock model of early
afterglow, a leptonic scenario that evolves in a homogeneous medium is proposed to revisit GRB 090510 and explain the multiwavelength light
curve observations presented in this burst. These observations are consistent with the evolution of a jet before and after the jet break. The
long-lasting LAT, X-ray and optical fluxes are explained in the synchrotron emission from the adiabatic forward shock. Synchrotron self-Compton
emission from the reverse shock is consistent with the bright LAT peak provided that progenitor environment is entrained with strong magnetic
fields. It could provide compelling evidence of magnetic field amplification in the neutron star merger.
Previous IAU Circulars 
