Gamma-ray Burst 091102

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 02 Nov 09 14:34:59 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     374598,   Seg_Num: 0
GRB_RA:           72.674d {+04h 50m 42s} (J2000),
                  72.634d {+04h 50m 32s} (current),
                  72.880d {+04h 51m 31s} (1950)
GRB_DEC:         -72.510d {-72d 30' 34"} (J2000),
                 -72.493d {-72d 29' 35"} (current),
                 -72.592d {-72d 35' 30"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5515 [cnts]    Image_Peak=362 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       28170 [cnts]
BKG_TIME:        52466.77 SOD {14:34:26.77} UT
BKG_DUR:         8 [sec]
GRB_DATE:        15137 TJD;   306 DOY;   09/11/02
GRB_TIME:        52478.35 SOD {14:34:38.35} UT
GRB_PHI:         -81.44 [deg]
GRB_THETA:        17.35 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     29.84 [sigma]
IMAGE_SIGNIF:    13.01 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +2  +0  +0  +0  +0 
SUN_POSTN:       217.89d {+14h 31m 33s}  -14.91d {-14d 54' 31"}
SUN_DIST:         89.63 [deg]   Sun_angle= 9.7 [hr] (West of Sun)
MOON_POSTN:       33.72d {+02h 14m 53s}  +18.72d {+18d 42' 59"}
MOON_DIST:        94.84 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      284.51,-34.71 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      307.62,-81.57 [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 = 204.94,14.60 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(0.0<100sec) coincident with the FERMI_GBM event (trignum=278865280).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 02 Nov 09 14:35:09 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     278865280
GRB_RA:           63.480d {+04h 13m 55s} (J2000),
                  63.458d {+04h 13m 50s} (current),
                  63.598d {+04h 14m 23s} (1950)
GRB_DEC:         -71.740d {-71d 44' 23"} (J2000),
                 -71.716d {-71d 42' 55"} (current),
                 -71.864d {-71d 51' 50"} (1950)
GRB_ERROR:       6.09 [deg radius, statistical only]
DATA_SIGNIF:     9.10 [sigma]
DATA_INTERVAL:   2.048 [sec]
GRB_DATE:        15137 TJD;   306 DOY;   09/11/02
GRB_TIME:        52478.36 SOD {14:34:38.36} UT
GRB_PHI:          92.00 [deg]
GRB_THETA:        98.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:       217.89d {+14h 31m 33s}  -14.91d {-14d 54' 31"}
SUN_DIST:         91.67 [deg]   Sun_angle= 10.3 [hr] (West of Sun)
MOON_POSTN:       33.72d {+02h 14m 53s}  +18.72d {+18d 43' 01"}
MOON_DIST:        92.68 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      285.14,-37.59 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      319.26,-79.36 [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/FERMI NOTICE
NOTICE_DATE:     Mon 02 Nov 09 14:35:04 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      59
TRIGGER_NUM:     278865280
GRB_RA:           49.650d {+03h 18m 36s} (J2000),
                  49.691d {+03h 18m 46s} (current),
                  49.442d {+03h 17m 46s} (1950)
GRB_DEC:         -63.817d {-63d 48' 59"} (J2000),
                 -63.781d {-63d 46' 51"} (current),
                 -63.997d {-63d 59' 49"} (1950)
GRB_ERROR:       14.95 [deg radius, statistical plus systematic]
GRB_INTEN:       140 [cnts/sec]
DATA_SIGNIF:     9.10 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        15137 TJD;   306 DOY;   09/11/02
GRB_TIME:        52478.36 SOD {14:34:38.36} UT
GRB_PHI:         101.00 [deg]
GRB_THETA:        95.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.66
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       0,0,1, 0,0,0, 0,0,0, 1,0,0, 0,0,
SUN_POSTN:       217.89d {+14h 31m 33s}  -14.91d {-14d 54' 31"}
SUN_DIST:        100.78 [deg]   Sun_angle= 11.2 [hr] (West of Sun)
MOON_POSTN:       33.72d {+02h 14m 53s}  +18.72d {+18d 43' 00"}
MOON_DIST:        83.43 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      280.42,-46.36 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      350.38,-73.16 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 49.62,1.40 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 02 Nov 09 14:38:23 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     374598,   Seg_Num: 0
GRB_RA:           72.674d {+04h 50m 42s} (J2000),
                  72.634d {+04h 50m 32s} (current),
                  72.880d {+04h 51m 31s} (1950)
GRB_DEC:         -72.510d {-72d 30' 34"} (J2000),
                 -72.493d {-72d 29' 35"} (current),
                 -72.592d {-72d 35' 30"} (1950)
GRB_DATE:        15137 TJD;   306 DOY;   09/11/02
GRB_TIME:        52478.35 SOD {14:34:38.35} UT
TRIGGER_INDEX:   146
GRB_PHI:         -81.44 [deg]
GRB_THETA:        17.35 [deg]
DELTA_TIME:      -37.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     29.84 [sigma]
IMAGE_SIGNIF:    13.01 [sigma]
LC_URL:          sw00374598000msb.lc
SUN_POSTN:       217.89d {+14h 31m 34s}  -14.91d {-14d 54' 33"}
SUN_DIST:         89.63 [deg]   Sun_angle= 9.7 [hr] (West of Sun)
MOON_POSTN:       33.75d {+02h 15m 00s}  +18.73d {+18d 43' 36"}
MOON_DIST:        94.84 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      284.51,-34.71 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      307.62,-81.57 [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 = 204.94,14.60 [deg].

GCN Circular #10117
E. A. Hoversten (PSU), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), P.A. Curran (MSSL-UCL), C. Guidorzi (U Ferrara), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA), J. Mao (INAF-OAB), P. T. O'Brien (U Leicester), C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU), M. A. Stark (PSU), M. C. Stroh (PSU), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the Swift Team:
At 14:34:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 091102 (trigger=374598). Swift did not slew immediately to the burst due to an observing constraint. The BAT on-board calculated location is RA, Dec 72.674, -72.510 which is
```
   RA(J2000) = 04h 50m 42s
   Dec(J2000) = -72d 30' 34"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 10 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+13.6 minutes. There will be no XRT or UVOT data until this time. We will issue another circular at when those data are available.
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:     Mon 02 Nov 09 14:51:11 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     374598,   Seg_Num: 0
POINT_RA:         72.666d {+04h 50m 40s} (J2000)
POINT_DEC:       -72.539d {-72d 32' 18"} (J2000)
IMG_START_DATE:  15137 TJD;   306 DOY;   09/11/02
IMG_START_TIME:  53459.09 SOD {14:50:59.09} UT,   980.7 [sec] since BAT Trigger Time
COUNTS:          1    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        0    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:     Mon 02 Nov 09 14:57:01 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     374598,   Seg_Num: 0
POINT_RA:         72.668d {+04h 50m 40s} (J2000)
POINT_DEC:       -72.538d {-72d 32' 17"} (J2000)
POINT_ROLL:      146.598d
IMG_START_DATE:  15137 TJD;   306 DOY;   09/11/02
IMG_START_TIME:  53464.18 SOD {14:51:04.18} UT,   985.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.626
N_STARS:         93
X_OFFSET:        274 [pixels]
Y_OFFSET:        539 [pixels]
X_MAX:           1233 [pixels]
Y_MAX:           1498 [pixels]
DET_THRESH:      26
PHOTO_THRESH:    16
SL_URL:          sw00374598000msufc0985.fits
SUN_POSTN:       217.90d {+14h 31m 37s}  -14.91d {-14d 54' 48"}
SUN_DIST:         89.60 [deg]   Sun_angle= 9.7 [hr] (West of Sun)
MOON_POSTN:       33.93d {+02h 15m 43s}  +18.78d {+18d 46' 55"}
MOON_DIST:        94.89 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      284.54,-34.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      307.47,-81.55 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 02 Nov 09 14:57:01 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     374598,   Seg_Num: 0
POINT_RA:         72.668d {+04h 50m 40s} (J2000)
POINT_DEC:       -72.538d {-72d 32' 17"} (J2000)
POINT_ROLL:      146.598d
IMG_START_DATE:  15137 TJD;   306 DOY;   09/11/02
IMG_START_TIME:  53464.18 SOD {14:51:04.18} UT,   985.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.626
N_STARS:         93
X_OFFSET:        274 [pixels]
Y_OFFSET:        539 [pixels]
X_MAX:           1233 [pixels]
Y_MAX:           1498 [pixels]
DET_THRESH:      26
PHOTO_THRESH:    16
SL_URL:          sw00374598000msufc0985.fits
SUN_POSTN:       217.90d {+14h 31m 37s}  -14.91d {-14d 54' 48"}
SUN_DIST:         89.60 [deg]   Sun_angle= 9.7 [hr] (West of Sun)
MOON_POSTN:       33.93d {+02h 15m 43s}  +18.78d {+18d 46' 55"}
MOON_DIST:        94.89 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      284.54,-34.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      307.47,-81.55 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 02 Nov 09 14:57:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     374598,   Seg_Num: 0
POINT_RA:         72.668d {+04h 50m 40s} (J2000)
POINT_DEC:       -72.538d {-72d 32' 17"} (J2000)
POINT_ROLL:      146.598d
IMG_START_DATE:  15137 TJD;   306 DOY;   09/11/02
IMG_START_TIME:  53464.18 SOD {14:51:04.18} UT,   985.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.626
N_STARS:         93
X_OFFSET:        274 [pixels]
Y_OFFSET:        539 [pixels]
X_MAX:           1233 [pixels]
Y_MAX:           1498 [pixels]
DET_THRESH:      26
PHOTO_THRESH:    16
SL_URL:          sw00374598000msufc0985.fits
SUN_POSTN:       217.90d {+14h 31m 37s}  -14.91d {-14d 54' 48"}
SUN_DIST:         89.60 [deg]   Sun_angle= 9.7 [hr] (West of Sun)
MOON_POSTN:       33.93d {+02h 15m 44s}  +18.78d {+18d 47' 01"}
MOON_DIST:        94.89 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      284.54,-34.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      307.47,-81.55 [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 02 Nov 09 14:58:39 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     374598,   Seg_Num: 0
POINT_RA:         72.668d {+04h 50m 40s} (J2000)
POINT_DEC:       -72.538d {-72d 32' 17"} (J2000)
ROLL:            146.598d
IMG_START_DATE:  15137 TJD;   306 DOY;   09/11/02
IMG_START_TIME:  53464.18 SOD {14:51:04.18} UT,   985.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     278866269
X_OFFSET:        593 [pixels]
Y_OFFSET:        858 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       753
Y_GRB_POS:       1018
BINNING_INDEX:   1
IM_URL:          sw00374598000msuni0991.fits
SUN_POSTN:       217.90d {+14h 31m 37s}  -14.91d {-14d 54' 49"}
SUN_DIST:         89.60 [deg]   Sun_angle= 9.7 [hr] (West of Sun)
MOON_POSTN:       33.94d {+02h 15m 47s}  +18.79d {+18d 47' 12"}
MOON_DIST:        94.89 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      284.54,-34.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      307.47,-81.55 [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:     Mon 02 Nov 09 14:59:06 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     374598,   Seg_Num: 0
POINT_RA:         72.668d {+04h 50m 40s} (J2000)
POINT_DEC:       -72.538d {-72d 32' 17"} (J2000)
ROLL:            146.598d
IMG_START_DATE:  15137 TJD;   306 DOY;   09/11/02
IMG_START_TIME:  53464.18 SOD {14:51:04.18} UT,   985.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     278866269
X_OFFSET:        593 [pixels]
Y_OFFSET:        858 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       753
Y_GRB_POS:       1018
BINNING_INDEX:   1
IM_URL:          sw00374598000msuni0991.fits
SUN_POSTN:       217.91d {+14h 31m 37s}  -14.91d {-14d 54' 50"}
SUN_DIST:         89.60 [deg]   Sun_angle= 9.7 [hr] (West of Sun)
MOON_POSTN:       33.95d {+02h 15m 48s}  +18.79d {+18d 47' 17"}
MOON_DIST:        94.89 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      284.54,-34.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      307.47,-81.55 [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 #10118
E. A. Hoversten (PSU) reports on behalf of the Swift/UVOT team:
UVOT observed GRB 091102 (Hoversten et al., GCN Circ 10117) with a finding chart exposure of 150 seconds with the White filter starting 985 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the expected extinction corresponding to E(B-V) of 0.07.
GCN Circular #10119
B. E. Schaefer (Louisiana State), F. Yuan (U Mich), S. B. Pandey (U Mich), report on behalf of the ROTSE collaboration:
ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to GRB 091102 (Swift trigger 374598; Hoversten et al., GCN 10117), producing images beginning 5.8 s after the GCN notice time. An automated response took the first image at 14:35:04.8 UT, 26.5 s after the burst, under fair conditions with occassional thin clouds and a bright Full Moon 96 degrees away. We took 10 5-sec, 10 20-sec and 100 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, for both single images and coadding into sets of 10. No XRT position is available. Individual images have limiting magnitudes ranging from 13.7-16.0; we set the following specific limits.
```
start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
14:35:04.8   14:35:09.8         5     14.6           26.5       N
14:35:04.8   14:37:16.8        50     15.5           26.5       Y
14:37:25.9   14:42:08.0       282     16.6          167.6       Y
```
GCN Circular #10120
J.A. Kennea, C. Pagani, E.A. Hoversten (PSU), P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team:
Using 289 s of XRT Photon Counting mode data and 1 UVOT images, we find a possible afterglow candidate with an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 72.61610, -72.51970 which is equivalent to:
```
RA (J2000):  04 50 27.87
Dec (J2000): -72 31 10.9
```
with an uncertainty of 2.2 arcsec (radius, 90% confidence), 72 arcseconds from the BAT position reported by Hoversten et al. (GCN #10117).
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).
Currently we cannot confirm any fading in this afterglow candidate. Observations are on-going.
This circular is an official product of the Swift-XRT team.
GCN Circular #10121
W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), 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), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 091102 (trigger #374598) (Hoversten, et al., GCN Circ. 10117). The BAT ground-calculated position is RA, Dec = 72.622, -72.527 deg which is
```
   RA(J2000)  =  04h 50m 29.3s 
   Dec(J2000) = -72d 31' 37.9" 
```
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 80%.
Because the s/c slewed for an observing constraint, the burst location went out of the BAT FOV at T+160 sec, and then came back into the FOV at T+900 sec. The mask-weighted light curve shows a couple slightly overlapping peaks starting at ~T-2 sec, and ending at ~T+20 sec. There is now measurable flux at T+900 sec when the location comes back into the FOV. T90 (15-350 keV) is 6.6 +- 0.5 sec (estimated error including systematics).
The time-averaged spectrum from T-0.8 to T+6.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.08 +- 0.12. The fluence in the 15-150 keV band is 5.2 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.26 sec in the 15-150 keV band is 1.4 +- 0.2 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/374598/BA/
GCN Circular #10122
A. de Ugarte Postigo (INAF-OAB), M. Jelinek, A.J. Castro-Tirado (IAA-CSIC), P. Kubanek (IPL UV, IAA-CSIC), J. Gorosabel, R. Cunniffe, S. Guziy (IAA-CSIC), P. Yock (Auckland Univ.), W.H. Allen (Vintage Lane Obs.), I. Bond (Massey Univ.), G. Christie (Stardome Obs.), report on behalf of a larger collaboration:
"We have observed the field of GRB 091102 (Hoversten et al. GCN 10117) with the 0.6m Yock-Allen robotic telescope (BOOTES-3) in Bleinheim, New Zealand. The observations were obtained with clear filter and began at 14:35:04 UT (26 seconds after the burst). As stated by Schaefer et al. (GCN 10119) using ROTSE-III data, there is no obvious counterpart within the BAT error box. Inspection of the XRT error circle shows a source at the South-Western edge that is present both in the DSS and in 2MASS. Combining early images we detect a further low signal source, with coordinates (J2000) 04:50:27.22, -72:31:10.3. We note however, that this is a preliminary reduction and that the detection cannot be secure at this point. In the following address we provide a finding chart indicating the location of the source:
http://www.iaa.es/~mates/091102_BOOTES3.jpg
```
 
t-t0(s)   Exp(s)   Mag 
===============================
72        39x2     19.07+/-0.35
406       107x2    19.36+/-0.35
530       60x5     > 19.96
83        19x30    > 19.25
2708      47x60    > 20.30
===============================
```
For the photometry we have used the star located at the coordinates (J2000) 04 50 26.58, -72 31 35.3, assuming a magnitude of 16.14."
GCN Circular #10123
R. Filgas, F. Olivares, T. Kruehler, J. Greiner, (all MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 091102 (Swift trigger 374598; Hoversten et al., GCN #10117) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP, 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla Observatory (Chile). Observations started on November 3 at 00:02 UT, 9.5 hours after the GRB trigger. They were performed from the beginning of the astronomical twilight at an average seeing of 2" and at an average airmass of 2.15.
Although the source at the South-Western edge of the 2.2" Swift/XRT error circle (Kennea et al., GCN #10120) reported by De Ugarte Postigo et al. (GCN #10122) is clearly seen, we do not detect the afterglow candidate in co-added images of 49.2 min integration time in g'r'i'z' and 40 min in JHK down to the following limiting magnitudes (all in the AB system):
```
r' > 23.1 mag,
i' > 22.9 mag,
z' > 23.1 mag,
J > 20.6 mag,
H > 20.5 mag, and
K > 19.0 mag,
```
calibrated against GROND zeropoints and 2MASS field stars. No corrections for the expected Galactic foreground extinction were made, which correspond to a reddening of E(B-V)=0.14 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #10124
E. A. Hoversten (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 091102 986s after the BAT trigger (Hoversten et al., GCN 10117). We do not detect any source at the enhanced Swift XRT position (Kennea et al. GCN 10120). UVOT magnitude 3-sigma upper limits are reported in the following table:
```
Filter   T_start   T_stop   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
WHITE       986     1136     147          > 20.05
v          1267     1287      19          > 17.18
b          1193     1213      19          > 18.09
u          1168     1188      19          > 17.70
uvw1       1144     1164      19          > 17.70
uvm2       1292     1301       9          > 16.61
uvw2       1243     1263      19          > 17.79
```
The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight of E_(B-V) = 0.07 mag (Schlegel et al. 1998). All photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular #10125
L. Vetere and E. A. Hoversten (PSU) report on behalf of the Swift-XRT team:
We have analysed 1.4 ks of XRT data for GRB 091102 (Hoversten et al. GCN Circ. 10117), from 988 s to 19 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position has already been determined by Kennea et al. (GCN Circ. 10120).
The PC light curve shows a steep drop at 1.3 ks after the BAT trigger with a decay index of alpha=2.9 +/- 0.6.
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.0 (+0.8, -0.6). The best-fitting absorption column is 2.4 (+2.5, -1.3) x 10^21 cm^-2, consistent with the Galactic value of 1.1 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.2 x 10^-11 (6.3 x 10^-11) erg cm^-2 count^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00374598.
This circular is an official product of the Swift-XRT team.
GCN Circular #10126
Arne Rau (MPE) reports on behalf of the Fermi GBM Team:
"At 14:34:38.36 UT on 2 November 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 091102A (trigger 278865280 / 091102607) which was also detected by the Swift-BAT (Hoversten et al. 2009, GCN 10117). The GBM on-ground location is consistent with the Swift/XRT position (Kennea et al. 2009, GCN 10120).
The angle from the Fermi LAT boresight is 94 degrees.
The GBM light curve consists of two peaks with a duration (T90) of about 7.3 +/- 0.4 s (8-1000 keV). The time-averaged spectrum from T0-1.792 s to T0+3.328 s is adequately by a simple power law function with index -1.24 +/- 0.03 (C-stat 478 for 387 d.o.f.).
The event fluence (8-1000 keV) in this time interval is (2.1 +/- 0.1)E-06 erg/cm^2. The 1.273-sec peak photon flux measured starting from T0+0.003 s in the 8-1000 keV band is 2.9 +/- 0.2 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #10127
Z. Cano (Liverpool JMU), C. Guidorzi (U. Ferrara), A. Melandri, C.G. Mundell, D.Bersier, N.R. Clay, S. Kobayashi, C.J. Mottram, R.J. Smith, I.A. Steele (Liverpool JMU), A. Gomboc (U. Ljubljana)on behalf of a larger collaboration report:
Following Swift detection of GRB 091102 (Hoversten et al. GCN Circ. 10117), Faulkes Telescope South (Australia) reacted automatically and began observing at 14:37:06 UT in BVRi. We detect no new source within the XRT error circle (Baumgartner et al., GCN 10121).
In our first R-band image, which is contemporaneous with the images taken by A. de Ugarte Postigo et al. (GCN 10122), we do not detect their afterglow candidate.
We have attached a finder chart of the GCN field (taken at T-To=186s):
http://www.fe.infn.it/u/guidorzi/GRB091102/091102_FTS_DM.jpg
We find the following upper limits, as calibrated against nearby USNO object 0174-0110239:
```
T_exp     T-T0(mid exposure)    mag_limit
-----------------------------------------
30s             186 s           R2 > 19.7
120s            2.07 hrs        B2 > 18.7
120s            2.18 hrs        I2 > 20.7
120s            2.12 hrs        R2 > 20.2
```
GCN Circular #10129
A. de Ugarte Postigo (INAF-OAB), A. Lundgren, C. de Breuck (ESO), A.J. Castro-Tirado, M. Jelinek (IAA-CSIC) report on behalf of a larger collaboration:
We have observed the field of GRB 091102 (Hoversten et al., GCN 10117) with using LABOCA/APEX from Chajnantor (Chile) at 870 um, under non optimal conditions (PWV~2.5mm). The observation consisted of 3 hours on target, with a total integration time of 2.2 hours and mean epoch 14.0 hours after the burst. The r.m.s of the image is 6.3 mJy and covers the complete BAT error box. In particular, we do not detect any new source at the location of the XRT position (Baumgartner et al., GCN 10121).
We acknowledge excellent support from APEX staff, in particular we thank Francisco Montenegro and Claudio Agurto.
GCN Circular #10132
K. Nishimoto, D. Suzuki, T. Sako, and F. Abe (STE Lab, Nagoya Univ.) on behalf of the MOA Collabration report:
We searched for an optical afterglow of GRB091102 (Hoversten et al. GCN 10117) starting from 14:57:07.8 UT on 2009 Nov 2 (22.5 minuts after the burst) with the MOA-II 1.8m telescope at Mt.John observatory in New Zealand. In a single image of a 60sec exposure with a wideband Red filter (center wavelength ~ 750nm and FWHM ~ 250nm), we did not find any object within the error circle of the Swift XRT source position (GCN 10120), except a star reported by BOOTES-3 (De Ugarte Postigo et al. GCN 10122) and GROND (R. Filgas et al. GCN 10123), which has I mag=19.15 and the separation of 1.6 arcsec from the center of the position. A 5 sigma upper limit is set in the I magnitude at 20.8 mag.
This photometry was done by using the DoPhot and calibrated against the USNO-B1.0 cataloged stars, and not corrected for the Galactic extinction.
GCN Report 255.1
GCN_Report 255.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_255_1.pdf by E.A. Hoversten at PSU titled: "Swift Observations on GRB 091102"
GCN Circular #10169
Y. Urata, H.M Lin (NCU), K. Yamaoka (Aoyama Gakuin U.), M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA), S. Sugita (Nagoya U.), Y. E. Nakagawa, T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.), N. Ohmori, E. Sonoda, K. Kono, H. Hayashi, A. Daikyuji, Y. Nishioka, K. Noda, M. Yamauchi (Univ. of Miyazaki), Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.), W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda, T. Sugasahara (Saitama U.), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report:
"The GRB 091102A (Swift-BAT trigger #374598,GCN Circ. 10117; Fermi-GBM trigger #278865280, GCN Circ. 10126) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV on 2009-11-02 14:34:37.863 UT (=T0).
The observed light curve shows a two-peaked structure, starting at T0-0.5 s and ending at T0+7.5 s, with a total duration (T90) of 6.6 s. The fluence in 100 - 1000 keV was 2.31 (-0.61, +0.39) x 10^-6 erg/cm^2. The 1-s peak flux measured from T0+0.5 s was 1.07 (-0.44, +0.24) photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-0.5 s to T0+7.5 s is well fitted by a single power-law with a photon index of 1.56 (-0.22, +0.24) (chi^2/d.o.f. = 15.2/14).
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

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Jochen Greiner, last update: 20-Apr-2024 [Disclaimer]