Gamma-ray Burst 091026

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:11:47 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     278255495
GRB_RA:           34.817d {+02h 19m 16s} (J2000),
                  34.662d {+02h 18m 39s} (current),
                  35.653d {+02h 22m 37s} (1950)
GRB_DEC:         -83.683d {-83d 40' 59"} (J2000),
                 -83.638d {-83d 38' 17"} (current),
                 -83.911d {-83d 54' 38"} (1950)
GRB_ERROR:       17.73 [deg radius, statistical plus systematic]
GRB_INTEN:       36 [cnts/sec]
DATA_SIGNIF:     5.40 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        15130 TJD;   299 DOY;   09/10/26
GRB_TIME:        47493.02 SOD {13:11:33.02} UT
GRB_PHI:         307.00 [deg]
GRB_THETA:       145.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.33
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       1,0,0, 0,1,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       211.03d {+14h 04m 07s}  -12.60d {-12d 35' 47"}
SUN_DIST:         83.75 [deg]   Sun_angle= 11.8 [hr] (West of Sun)
MOON_POSTN:      311.02d {+20h 44m 06s}  -16.84d {-16d 50' 20"}
MOON_DIST:        72.56 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      300.12,-32.96 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      284.97,-69.54 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 324.33,7.73 [deg].

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:11:51 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     373871,   Seg_Num: 0
GRB_RA:          276.583d {+18h 26m 20s} (J2000),
                 277.508d {+18h 30m 02s} (current),
                 271.836d {+18h 07m 21s} (1950)
GRB_DEC:         -86.121d {-86d 07' 16"} (J2000),
                 -86.115d {-86d 06' 52"} (current),
                 -86.142d {-86d 08' 30"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5031 [cnts]    Image_Peak=267 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   148     E_range: 25-100 keV
BKG_INTEN:       28697 [cnts]
BKG_TIME:        47474.79 SOD {13:11:14.79} UT
BKG_DUR:         8 [sec]
GRB_DATE:        15130 TJD;   299 DOY;   09/10/26
GRB_TIME:        47490.15 SOD {13:11:30.15} UT
GRB_PHI:         -110.78 [deg]
GRB_THETA:        33.06 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     25.94 [sigma]
IMAGE_SIGNIF:    12.08 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +1  +0  +0 -24  +0 
SUN_POSTN:       211.03d {+14h 04m 07s}  -12.60d {-12d 35' 47"}
SUN_DIST:         75.88 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.02d {+20h 44m 06s}  -16.84d {-16d 50' 19"}
MOON_DIST:        69.93 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.25,-26.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      270.97,-62.70 [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 = 69.04,-20.02 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(3.0<100sec) coincident with the FERMI_GBM event (trignum=278255495).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:12:06 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      54
TRIGGER_NUM:     278255495
GRB_RA:           63.760d {+04h 15m 02s} (J2000),
                  63.403d {+04h 13m 37s} (current),
                  65.632d {+04h 22m 32s} (1950)
GRB_DEC:         -84.220d {-84d 13' 11"} (J2000),
                 -84.196d {-84d 11' 43"} (current),
                 -84.339d {-84d 20' 20"} (1950)
GRB_ERROR:       6.49 [deg radius, statistical only]
DATA_SIGNIF:     8.50 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        15130 TJD;   299 DOY;   09/10/26
GRB_TIME:        47493.02 SOD {13:11:33.02} UT
GRB_PHI:         306.00 [deg]
GRB_THETA:       142.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:       211.03d {+14h 04m 07s}  -12.60d {-12d 35' 47"}
SUN_DIST:         82.32 [deg]   Sun_angle= 9.8 [hr] (West of Sun)
MOON_POSTN:      311.03d {+20h 44m 06s}  -16.84d {-16d 50' 17"}
MOON_DIST:        75.44 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      297.72,-30.68 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      278.10,-71.58 [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/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:13:21 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     373871,   Seg_Num: 0
GRB_RA:          276.6033d {+18h 26m 24.79s} (J2000),
                 277.5266d {+18h 30m 06.37s} (current),
                 271.8668d {+18h 07m 28.03s} (1950)
GRB_DEC:         -86.1119d {-86d 06' 42.8"} (J2000),
                 -86.1052d {-86d 06' 18.6"} (current),
                 -86.1325d {-86d 07' 57.0"} (1950)
GRB_ERROR:       4.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       3.42e-09 [erg/cm2/sec]
GRB_SIGNIF:      10.44 [sigma]
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47568.89 SOD {13:12:48.89} UT,   78.7 [sec] since BAT Trigger Time
TAM[0-3]:        327.63 237.25 261.28 243.53
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       211.03d {+14h 04m 07s}  -12.60d {-12d 35' 48"}
SUN_DIST:         75.88 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.04d {+20h 44m 09s}  -16.83d {-16d 50' 04"}
MOON_DIST:        69.93 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.26,-26.64 [deg] galactic lon,lat of the burst
ECL_COORDS:      270.97,-62.69 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.57 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:13:32 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     373871,   Seg_Num: 0
GRB_RA:          276.6033d {+18h 26m 24.7s} (J2000),
                 277.5266d {+18h 30m 06.3s} (current),
                 271.8668d {+18h 07m 28.0s} (1950)
GRB_DEC:         -86.1119d {-86d 06' 42.8"} (J2000),
                 -86.1052d {-86d 06' 18.6"} (current),
                 -86.1325d {-86d 07' 57.0"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       109 [cnts]
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47568.89 SOD {13:12:48.89} UT,   78.7 [sec] since BAT Trigger Time
CENTROID_X:      263.91,  raw= 264  [pixels]
CENTROID_Y:      283.26,  raw= 283  [pixels]
ROLL:            293.29 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -34.73
GRB_POS_XRT_Z:   -90.49
IMAGE_URL:       sw00373871000msxps_rw.img
SUN_POSTN:       211.03d {+14h 04m 07s}  -12.60d {-12d 35' 49"}
SUN_DIST:         75.88 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.04d {+20h 44m 09s}  -16.83d {-16d 50' 02"}
MOON_DIST:        69.93 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.26,-26.64 [deg] galactic lon,lat of the burst
ECL_COORDS:      270.97,-62.69 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:13:37 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     373871,   Seg_Num: 0
GRB_RA:          276.6033d {+18h 26m 24.7s} (J2000),
                 277.5266d {+18h 30m 06.3s} (current),
                 271.8668d {+18h 07m 28.0s} (1950)
GRB_DEC:         -86.1119d {-86d 06' 42.8"} (J2000),
                 -86.1052d {-86d 06' 18.6"} (current),
                 -86.1325d {-86d 07' 57.0"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       109 [cnts]
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47568.89 SOD {13:12:48.89} UT,   78.7 [sec] since BAT Trigger Time
CENTROID_X:      263.91,  raw= 264  [pixels]
CENTROID_Y:      283.26,  raw= 283  [pixels]
ROLL:            293.29 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -34.73
GRB_POS_XRT_Z:   -90.49
IMAGE_URL:       sw00373871000msxps_rw.img
SUN_POSTN:       211.03d {+14h 04m 07s}  -12.60d {-12d 35' 49"}
SUN_DIST:         75.88 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.04d {+20h 44m 09s}  -16.83d {-16d 50' 01"}
MOON_DIST:        69.93 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.26,-26.64 [deg] galactic lon,lat of the burst
ECL_COORDS:      270.97,-62.69 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:15:05 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     373871,   Seg_Num: 0
GRB_RA:          276.583d {+18h 26m 20s} (J2000),
                 277.508d {+18h 30m 02s} (current),
                 271.836d {+18h 07m 21s} (1950)
GRB_DEC:         -86.121d {-86d 07' 16"} (J2000),
                 -86.115d {-86d 06' 52"} (current),
                 -86.142d {-86d 08' 30"} (1950)
GRB_DATE:        15130 TJD;   299 DOY;   09/10/26
GRB_TIME:        47490.15 SOD {13:11:30.15} UT
TRIGGER_INDEX:   148
GRB_PHI:         -110.78 [deg]
GRB_THETA:        33.06 [deg]
DELTA_TIME:      64.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     25.94 [sigma]
IMAGE_SIGNIF:    12.08 [sigma]
LC_URL:          sw00373871000msb.lc
SUN_POSTN:       211.03d {+14h 04m 07s}  -12.60d {-12d 35' 50"}
SUN_DIST:         75.88 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.05d {+20h 44m 12s}  -16.83d {-16d 49' 46"}
MOON_DIST:        69.95 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.25,-26.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      270.97,-62.70 [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 = 69.04,-20.02 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:15:50 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.874d {+18h 27m 30s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
POINT_ROLL:      293.303d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47577.38 SOD {13:12:57.38} UT,   87.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.289
N_STARS:         104
X_OFFSET:        632 [pixels]
Y_OFFSET:        472 [pixels]
X_MAX:           1591 [pixels]
Y_MAX:           1431 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00373871000msufc0087.fits
SUN_POSTN:       211.03d {+14h 04m 08s}  -12.60d {-12d 35' 51"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.06d {+20h 44m 14s}  -16.83d {-16d 49' 39"}
MOON_DIST:        69.94 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.01,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:16:20 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.874d {+18h 27m 30s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
POINT_ROLL:      293.303d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47577.38 SOD {13:12:57.38} UT,   87.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.289
N_STARS:         104
X_OFFSET:        632 [pixels]
Y_OFFSET:        472 [pixels]
X_MAX:           1591 [pixels]
Y_MAX:           1431 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00373871000msufc0087.fits
SUN_POSTN:       211.03d {+14h 04m 08s}  -12.60d {-12d 35' 51"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.06d {+20h 44m 15s}  -16.83d {-16d 49' 34"}
MOON_DIST:        69.95 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.01,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:15:50 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.874d {+18h 27m 30s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
POINT_ROLL:      293.303d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47577.38 SOD {13:12:57.38} UT,   87.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.289
N_STARS:         104
X_OFFSET:        632 [pixels]
Y_OFFSET:        472 [pixels]
X_MAX:           1591 [pixels]
Y_MAX:           1431 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00373871000msufc0087.fits
SUN_POSTN:       211.03d {+14h 04m 08s}  -12.60d {-12d 35' 51"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.06d {+20h 44m 14s}  -16.83d {-16d 49' 39"}
MOON_DIST:        69.94 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.01,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:17:16 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.874d {+18h 27m 30s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
ROLL:            293.303d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47577.38 SOD {13:12:57.38} UT,   87.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     278255582
X_OFFSET:        998 [pixels]
Y_OFFSET:        835 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1158
Y_GRB_POS:       995
BINNING_INDEX:   1
IM_URL:          sw00373871000msuni0093.fits
SUN_POSTN:       211.03d {+14h 04m 08s}  -12.60d {-12d 35' 52"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.07d {+20h 44m 16s}  -16.82d {-16d 49' 24"}
MOON_DIST:        69.95 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.01,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:17:36 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.874d {+18h 27m 30s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
ROLL:            293.303d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47577.38 SOD {13:12:57.38} UT,   87.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     278255582
X_OFFSET:        998 [pixels]
Y_OFFSET:        835 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1158
Y_GRB_POS:       995
BINNING_INDEX:   1
IM_URL:          sw00373871000msuni0093.fits
SUN_POSTN:       211.03d {+14h 04m 08s}  -12.60d {-12d 35' 52"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.07d {+20h 44m 17s}  -16.82d {-16d 49' 21"}
MOON_DIST:        69.95 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.01,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:20:21 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     373871,   Seg_Num: 0
GRB_RA:          276.5933d {+18h 26m 22.39s} (J2000),
                 277.5163d {+18h 30m 03.90s} (current),
                 271.8583d {+18h 07m 25.98s} (1950)
GRB_DEC:         -86.1105d {-86d 06' 37.8"} (J2000),
                 -86.1038d {-86d 06' 13.6"} (current),
                 -86.1311d {-86d 07' 51.8"} (1950)
GRB_ERROR:       4.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47758.00 SOD {13:15:58.00} UT,   267.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       211.03d {+14h 04m 08s}  -12.60d {-12d 35' 54"}
SUN_DIST:         75.87 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.09d {+20h 44m 22s}  -16.82d {-16d 48' 53"}
MOON_DIST:        69.95 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.26,-26.64 [deg] galactic lon,lat of the burst
ECL_COORDS:      270.97,-62.69 [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.

GCN Circular #10081
C. B. Markwardt (CRESST/GSFC/UMD), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), D. Grupe (PSU), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA), J. Mao (INAF-OAB), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), P. Roming (PSU), B. Sbarufatti (INAF-IASFPA), M. H. Siegel (PSU) and M. Stamatikos (OSU/NASA/GSFC) report on behalf of the Swift Team:
At 13:11:30 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 091026 (trigger=373871). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 276.583, -86.121 which is
```
   RA(J2000)  =  18h 26m 20s
   Dec(J2000) = -86d 07' 16"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a FRED pulse with a duration of about 20 sec. The peak count rate was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 13:12:48.9 UT, 78.7 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 276.59337, -86.11056 which is equivalent to:
```
   RA(J2000)  = 18h 26m 22.41s
   Dec(J2000) = -86d 06' 38.0"
```
with an uncertainty of 4.0 arcseconds (radius, 90% containment). This location is 37 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 in excess of the Galactic value (8.36e+20 cm^-2, Kalberla et al. 2005), with an excess column of 3.6 (+2.72/-2.29) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 3.42e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 87 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 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.13.
Burst Advocate for this burst is C. B. Markwardt (Craig.Markwardt AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:23:33 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.921d {+18h 27m 41s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
POINT_ROLL:      293.258d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47790.08 SOD {13:16:30.08} UT,   299.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.579
N_STARS:         71
X_OFFSET:        678 [pixels]
Y_OFFSET:        515 [pixels]
X_MAX:           1637 [pixels]
Y_MAX:           1474 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00373871000msufc0299.fits
SUN_POSTN:       211.04d {+14h 04m 09s}  -12.60d {-12d 35' 57"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.12d {+20h 44m 29s}  -16.81d {-16d 48' 21"}
MOON_DIST:        69.97 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.02,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:23:55 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.921d {+18h 27m 41s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
POINT_ROLL:      293.258d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47790.08 SOD {13:16:30.08} UT,   299.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.579
N_STARS:         71
X_OFFSET:        678 [pixels]
Y_OFFSET:        515 [pixels]
X_MAX:           1637 [pixels]
Y_MAX:           1474 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00373871000msufc0299.fits
SUN_POSTN:       211.04d {+14h 04m 09s}  -12.60d {-12d 35' 57"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.12d {+20h 44m 29s}  -16.81d {-16d 48' 17"}
MOON_DIST:        69.97 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.02,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:23:33 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.921d {+18h 27m 41s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
POINT_ROLL:      293.258d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47790.08 SOD {13:16:30.08} UT,   299.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.579
N_STARS:         71
X_OFFSET:        678 [pixels]
Y_OFFSET:        515 [pixels]
X_MAX:           1637 [pixels]
Y_MAX:           1474 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00373871000msufc0299.fits
SUN_POSTN:       211.04d {+14h 04m 09s}  -12.60d {-12d 35' 57"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.12d {+20h 44m 29s}  -16.81d {-16d 48' 21"}
MOON_DIST:        69.97 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.02,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:24:55 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.921d {+18h 27m 41s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
ROLL:            293.258d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47790.08 SOD {13:16:30.08} UT,   299.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     278255795
X_OFFSET:        998 [pixels]
Y_OFFSET:        835 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1158
Y_GRB_POS:       995
BINNING_INDEX:   1
IM_URL:          sw00373871000msuni0305.fits
SUN_POSTN:       211.04d {+14h 04m 09s}  -12.60d {-12d 35' 58"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.13d {+20h 44m 31s}  -16.80d {-16d 48' 07"}
MOON_DIST:        69.97 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.02,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:25:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.921d {+18h 27m 41s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
ROLL:            293.258d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  47790.08 SOD {13:16:30.08} UT,   299.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     278255795
X_OFFSET:        998 [pixels]
Y_OFFSET:        835 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1158
Y_GRB_POS:       995
BINNING_INDEX:   1
IM_URL:          sw00373871000msuni0305.fits
SUN_POSTN:       211.04d {+14h 04m 09s}  -12.60d {-12d 35' 59"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.13d {+20h 44m 32s}  -16.80d {-16d 48' 04"}
MOON_DIST:        69.97 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.02,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:31:28 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.921d {+18h 27m 41s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
POINT_ROLL:      293.258d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  48367.23 SOD {13:26:07.23} UT,   877.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.143
N_STARS:         190
X_OFFSET:        438 [pixels]
Y_OFFSET:        275 [pixels]
X_MAX:           1877 [pixels]
Y_MAX:           1714 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00373871000msufc0877.fits
SUN_POSTN:       211.04d {+14h 04m 10s}  -12.60d {-12d 36' 04"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.18d {+20h 44m 44s}  -16.78d {-16d 47' 01"}
MOON_DIST:        69.99 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.02,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:31:28 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.921d {+18h 27m 41s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
POINT_ROLL:      293.258d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  48367.23 SOD {13:26:07.23} UT,   877.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.143
N_STARS:         190
X_OFFSET:        438 [pixels]
Y_OFFSET:        275 [pixels]
X_MAX:           1877 [pixels]
Y_MAX:           1714 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00373871000msufc0877.fits
SUN_POSTN:       211.04d {+14h 04m 10s}  -12.60d {-12d 36' 04"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.18d {+20h 44m 44s}  -16.78d {-16d 47' 01"}
MOON_DIST:        69.99 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.02,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:32:08 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.921d {+18h 27m 41s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
POINT_ROLL:      293.258d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  48367.23 SOD {13:26:07.23} UT,   877.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.143
N_STARS:         190
X_OFFSET:        438 [pixels]
Y_OFFSET:        275 [pixels]
X_MAX:           1877 [pixels]
Y_MAX:           1714 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00373871000msufc0877.fits
SUN_POSTN:       211.04d {+14h 04m 10s}  -12.60d {-12d 36' 04"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.19d {+20h 44m 45s}  -16.78d {-16d 46' 54"}
MOON_DIST:        69.99 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.02,-62.72 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 26 Oct 09 13:32:37 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.921d {+18h 27m 41s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
ROLL:            293.258d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  48367.23 SOD {13:26:07.23} UT,   877.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     278256372
X_OFFSET:        997 [pixels]
Y_OFFSET:        834 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1157
Y_GRB_POS:       994
BINNING_INDEX:   1
IM_URL:          sw00373871000msuni0883.fits
SUN_POSTN:       211.04d {+14h 04m 10s}  -12.60d {-12d 36' 05"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.19d {+20h 44m 46s}  -16.78d {-16d 46' 49"}
MOON_DIST:        69.99 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.02,-62.72 [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 26 Oct 09 13:33:02 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     373871,   Seg_Num: 0
POINT_RA:        276.921d {+18h 27m 41s} (J2000)
POINT_DEC:       -86.131d {-86d 07' 50"} (J2000)
ROLL:            293.258d
IMG_START_DATE:  15130 TJD;   299 DOY;   09/10/26
IMG_START_TIME:  48367.23 SOD {13:26:07.23} UT,   877.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     278256372
X_OFFSET:        997 [pixels]
Y_OFFSET:        834 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1157
Y_GRB_POS:       994
BINNING_INDEX:   1
IM_URL:          sw00373871000msuni0883.fits
SUN_POSTN:       211.04d {+14h 04m 10s}  -12.60d {-12d 36' 05"}
SUN_DIST:         75.90 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      311.20d {+20h 44m 47s}  -16.78d {-16d 46' 45"}
MOON_DIST:        70.00 [deg]
MOON_ILLUM:      55 [%]
GAL_COORDS:      307.24,-26.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      271.02,-62.72 [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 #10082
P.A. Evans and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT Team:
Using the full set of promptly downlinked XRT event mode data totalling 760 s in Photon Counting mode, and 2 UVOT images, we find an enhanced XRT position for GRB 091026 (Markwardt et al. GCN Circ. 10081) of RA, Dec = 276.5725, -86.1115 (degrees) which is equivalent to:
```
RA  (J2000.0) = 18 26 17.41
DEC (J2000.0) = -86 06 41.5
```
with an uncertainty of 2.1 arcsec (radius, 90% containment).
This circular is an official product of the Swift-XRT team.
GCN Circular #10084
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 512 s of XRT Photon Counting mode data and 1 UVOT images for GRB 091026, 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 = 276.57076, -86.11163 which is equivalent to:
```
RA (J2000): 18h 26m 16.98s
Dec (J2000): -86d 06' 41.9"
```
with an uncertainty of 1.9 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #10085
P.A. Evans, J.P. Osborne (U. Leicester) and C. B. Markwardt (CRESST/GSFC/UMD) report on behalf of the Swift-XRT team:
We have analysed 2.2 ks of XRT data for GRB 091026 (Markwardt et al. GCN Circ. 10081), from 85 s to 6.8 ks after the BAT trigger. The data comprise 326 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN. Circ 10084).
The light curve shows three flares in the first snapshot, with peaks at T0+180 s, T0+340 s and T0+~890 s. The orbital gap interrupts the final flare, making its peak time somewhat uncertain. If these flares are disregarded (i.e. fitting only the data from 85 s to 150 s and 2 ks to 6.8 ks), the underlying light curve can be modelled with an initial power-law decay with an index of alpha=3.40 (+0.31, -0.26), followed by a break at T+149 s to an alpha of 0.98 (+0.07, -1.7).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.97 (+/-0.08). The best-fitting absorption column is 2.93 (+0.28, -0.27) x 10^21 cm^-2, in excess of the Galactic value of 8.4 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.01 (+0.18, -0.17) and a best-fitting absorption column of 3.5 (+0.7, -0.6) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.6 x 10^-11 (7.6 x 10^-11) erg cm^-2 count^-1.
If the light curve continues to decay with a power-law decay index of 0.98, the count rate at T+24 hours will be 0.018 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.3 x 10^-13 (1.4 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00373871.
This circular is an official product of the Swift-XRT team.
GCN Circular #10087
P.A. Curran (MSSL-UCL) and C.B. Markwardt (CRESST/GSFC/UMD) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 091026 87 s after the BAT trigger (Markwardt et al., GCN 10081). No optical afterglow consistent with the enhanced XRT position (Evans et al., GCN 10084) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposures and subsequent exposures are:
```
Filter          T_start(s)   T_stop(s)    Exp(s)    Mag
-----------------------------------------------------------
white (FC)      87           237          147       >21.00
u (FC)          300          550          246       >20.36

white           87           12292        950       >22.09
v               629          5959         236       >19.63
b               555          6778         235       >20.62
u               300          6573         462       >20.72
w1              678          6369         236       >20.09
m2              826          6164         216       >19.85
w2              605          16097        561       >20.70
```
The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.13 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #10089
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), 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 091026 (trigger #373871) (Markwardt, et al., GCN Circ. 10081). The BAT ground-calculated position is RA, Dec = 276.657, -86.113 deg which is
```
   RA(J2000)  =  18h 26m 37.7s 
   Dec(J2000) = -86d 06' 47.2" 
```
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 36%.
The mask-weighted light curve shows a single FRED-like peak which starts to rise around T-5 sec, peaks near T+0 sec, and has a long tail extending to about T+120 sec. T90 (15-350 keV) is 41.6 +- 7.2 sec (estimated error including systematics).
The time-averaged spectrum from T-3.7 to T+47.9 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.53 +- 0.11. The fluence in the 15-150 keV band is 1.8 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.18 sec in the 15-150 keV band is 2.2 +- 0.3 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/373871/BA/
GCN Circular #10091
Robert Filgas (Tautenburg Obs.), Adria Updike (Clemson University), Arne Rau, and Jochen Greiner (both MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 091026 (Swift trigger 373871; Markwardt et al., GCN #10081) 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 at 00:48 UT on Oct 27, 2009, 11.6 hours after the GRB trigger. They were performed at an average seeing of 2" and at an average airmass of 1.94.
We do not detect a source within the Swift-XRT error circle reported by Evans et al. (GCN #10084) down to
```
g' > 24.8 mag,
r' > 24.2 mag,
i' > 23.9 mag,
z' > 23.7 mag,
J  > 22.2 mag,
H  > 21.3 mag and
K  > 20.2 mag.
```
Magnitudes are given in the AB system and calibrated against USNO as well as 2MASS field stars, and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.13 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #10094
N. Ohmori, E. Sonoda, K. Kono, H. Hayashi, A. Daikyuji, Y. Nishioka, K. Noda, M. Yamauchi (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.), Y. Hanabata, T. Uehara, 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 long GRB 091026 (Swift-BAT trigger #373871; Markwardt et al., GCN Circ. 10081) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 13:11:29.812 UT (=T0).
The observed light curve shows a multi-peaked structure, starting at T0-1 s and ending at T0+13 s, with a total duration (T90) of about 9 s. The fluence in 100 - 1000 keV was 1.47 (-0.40, +0.29) x 10^6 erg/cm^2. The 1-s peak flux measured from T0+1.5 s was 0.59 (-0.30, +0.19) photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-1 s to T0+13 s is well fitted by a single power-law with a photon index of 1.86 (-0.25, +0.33) (chi^2/d.o.f. = 77/50).
All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included.
The light curves for this burst will be available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
GCN Circular #10133
K. Nishimoto, T. Sako (Nagoya Univ.) on behalf of the MOA Collaboration, M. Kurita, T. Nagayama (Nagoya Univ.) on behalf of the IRSF Collabration report:
We searched for a NIR afterglow of GRB091026 (Markwardt et al., GCN 10081) starting from 18:43:32.3 UT on 2009 Oct 26 (5.5 hours after the burst) with the SIRIUS on the IRSF 1.4m telescope at SAAO in South Africa. In images of a 300sec exposure with J, H and Ks filter, we did not find any object within the error circle of the Swift XRT source position (Evans. et al., GCN 10084).
A 5 sigma upper limits are the followings.
```
J > 18.35
H > 17.39
K > 16.70
```
This photometry was done by using the DoPhot and calibrated against the 2MASS cataloged stars

Back to JG's homepage

Jochen Greiner, last update: 04-Nov-2009 [Disclaimer]