Gamma-ray Burst 090904B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:25:25 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     361831,   Seg_Num: 0
GRB_RA:          264.191d {+17h 36m 46s} (J2000),
                 264.341d {+17h 37m 22s} (current),
                 263.421d {+17h 33m 41s} (1950)
GRB_DEC:         -25.212d {-25d 12' 43"} (J2000),
                 -25.218d {-25d 13' 02"} (current),
                 -25.182d {-25d 10' 55"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       18053 [cnts]    Image_Peak=239 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   488     E_range: 50-350 keV
BKG_INTEN:       147213 [cnts]
BKG_TIME:        5002.94 SOD {01:23:22.94} UT
BKG_DUR:         40 [sec]
GRB_DATE:        15078 TJD;   247 DOY;   09/09/04
GRB_TIME:        5058.11 SOD {01:24:18.11} UT
GRB_PHI:         166.95 [deg]
GRB_THETA:        52.56 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     16.73 [sigma]
IMAGE_SIGNIF:    7.98 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +3  -2  +0  +1 +22  +0 
SUN_POSTN:       163.08d {+10h 52m 19s}   +7.19d {+07d 11' 24"}
SUN_DIST:        103.21 [deg]   Sun_angle= -6.8 [hr] (East of Sun)
MOON_POSTN:      335.70d {+22h 22m 49s}   -7.02d {-07d 01' 12"}
MOON_DIST:        70.18 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      264.74, -1.88 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
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 = 197.85,-1.33 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(5.0<100sec) coincident with the FERMI_GBM event (trignum=273720255).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:24:30 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     273720255
GRB_RA:          257.367d {+17h 09m 28s} (J2000),
                 257.514d {+17h 10m 03s} (current),
                 256.605d {+17h 06m 25s} (1950)
GRB_DEC:         -24.050d {-24d 03' 00"} (J2000),
                 -24.062d {-24d 03' 41"} (current),
                 -23.987d {-23d 59' 13"} (1950)
GRB_ERROR:       26.38 [deg radius, statistical plus systematic]
GRB_INTEN:       68 [cnts/sec]
DATA_SIGNIF:     4.80 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        15078 TJD;   247 DOY;   09/09/04
GRB_TIME:        5053.93 SOD {01:24:13.93} UT
GRB_PHI:         111.00 [deg]
GRB_THETA:       115.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.77
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   2%  Generic Transient
DETECTORS:       0,0,0, 0,0,0, 0,1,0, 0,1,0, 0,0,
SUN_POSTN:       163.08d {+10h 52m 19s}   +7.19d {+07d 11' 25"}
SUN_DIST:         96.95 [deg]   Sun_angle= -6.3 [hr] (East of Sun)
MOON_POSTN:      335.70d {+22h 22m 47s}   -7.02d {-07d 01' 24"}
MOON_DIST:        76.38 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      359.61,  9.44 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      258.48, -1.11 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 320.23,13.50 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:24:36 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      57
TRIGGER_NUM:     273720255
GRB_RA:          266.800d {+17h 47m 12s} (J2000),
                 266.941d {+17h 47m 46s} (current),
                 266.070d {+17h 44m 17s} (1950)
GRB_DEC:         -17.883d {-17d 52' 59"} (J2000),
                 -17.886d {-17d 53' 09"} (current),
                 -17.866d {-17d 51' 57"} (1950)
GRB_ERROR:       10.08 [deg radius, statistical plus systematic]
GRB_INTEN:       169 [cnts/sec]
DATA_SIGNIF:     10.50 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        15078 TJD;   247 DOY;   09/09/04
GRB_TIME:        5053.93 SOD {01:24:13.93} UT
GRB_PHI:         115.00 [deg]
GRB_THETA:       105.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.81
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      93%  GRB
2nd_MOST_LIKELY:   4%  SGR_1806n20
DETECTORS:       0,0,0, 0,0,0, 0,1,0, 0,1,0, 0,0,
SUN_POSTN:       163.08d {+10h 52m 19s}   +7.19d {+07d 11' 25"}
SUN_DIST:        105.35 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      335.70d {+22h 22m 47s}   -7.02d {-07d 01' 22"}
MOON_DIST:        67.68 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        9.66,  5.41 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      266.94,  5.52 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 320.23,13.50 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:25:07 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      56
TRIGGER_NUM:     273720255
GRB_RA:          257.190d {+17h 08m 46s} (J2000),
                 257.336d {+17h 09m 21s} (current),
                 256.437d {+17h 05m 45s} (1950)
GRB_DEC:         -22.630d {-22d 37' 47"} (J2000),
                 -22.642d {-22d 38' 30"} (current),
                 -22.566d {-22d 33' 58"} (1950)
GRB_ERROR:       3.75 [deg radius, statistical only]
DATA_SIGNIF:     12.70 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        15078 TJD;   247 DOY;   09/09/04
GRB_TIME:        5053.93 SOD {01:24:13.93} UT
GRB_PHI:         110.00 [deg]
GRB_THETA:       114.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:       163.08d {+10h 52m 19s}   +7.19d {+07d 11' 25"}
SUN_DIST:         96.67 [deg]   Sun_angle= -6.3 [hr] (East of Sun)
MOON_POSTN:      335.70d {+22h 22m 48s}   -7.02d {-07d 01' 16"}
MOON_DIST:        76.60 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        0.69, 10.39 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      258.19,  0.29 [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:     Fri 04 Sep 09 01:25:23 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      67
TRIGGER_NUM:     273720255
GRB_RA:          266.000d {+17h 44m 00s} (J2000),
                 266.152d {+17h 44m 36s} (current),
                 265.217d {+17h 40m 52s} (1950)
GRB_DEC:         -27.160d {-27d 09' 35"} (J2000),
                 -27.164d {-27d 09' 48"} (current),
                 -27.139d {-27d 08' 18"} (1950)
GRB_ERROR:       4.52 [deg radius, statistical only]
DATA_SIGNIF:     17.00 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        15078 TJD;   247 DOY;   09/09/04
GRB_TIME:        5053.93 SOD {01:24:13.93} UT
GRB_PHI:         120.00 [deg]
GRB_THETA:       113.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:       163.08d {+10h 52m 19s}   +7.19d {+07d 11' 24"}
SUN_DIST:        104.88 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      335.70d {+22h 22m 48s}   -7.02d {-07d 01' 12"}
MOON_DIST:        68.63 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        1.33,  1.23 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      266.43, -3.77 [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:     Fri 04 Sep 09 01:26:40 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.190d {+17h 36m 45s} (J2000)
POINT_DEC:       -25.216d {-25d 12' 57"} (J2000)
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5192.26 SOD {01:26:32.26} UT,   134.2 [sec] since BAT Trigger Time
COUNTS:          62    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        4    Max_iter_allowed= 4
ERROR_CODE:      2
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        Algorithm did not converge; too many iterations.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:28:02 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     361831,   Seg_Num: 0
GRB_RA:          264.191d {+17h 36m 46s} (J2000),
                 264.341d {+17h 37m 22s} (current),
                 263.421d {+17h 33m 41s} (1950)
GRB_DEC:         -25.212d {-25d 12' 43"} (J2000),
                 -25.218d {-25d 13' 02"} (current),
                 -25.182d {-25d 10' 55"} (1950)
GRB_DATE:        15078 TJD;   247 DOY;   09/09/04
GRB_TIME:        5058.11 SOD {01:24:18.11} UT
TRIGGER_INDEX:   488
GRB_PHI:         166.95 [deg]
GRB_THETA:        52.56 [deg]
DELTA_TIME:      -76.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     16.73 [sigma]
IMAGE_SIGNIF:    7.98 [sigma]
LC_URL:          sw00361831000msb.lc
SUN_POSTN:       163.08d {+10h 52m 20s}   +7.19d {+07d 11' 22"}
SUN_DIST:        103.21 [deg]   Sun_angle= -6.8 [hr] (East of Sun)
MOON_POSTN:      335.72d {+22h 22m 53s}   -7.01d {-07d 00' 37"}
MOON_DIST:        70.20 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      264.74, -1.88 [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 = 197.85,-1.33 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:30:58 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.189d {+17h 36m 45s} (J2000)
POINT_DEC:       -25.216d {-25d 12' 56"} (J2000)
POINT_ROLL:      271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5195.59 SOD {01:26:35.59} UT,   137.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.572
N_STARS:         56
X_OFFSET:        474 [pixels]
Y_OFFSET:        563 [pixels]
X_MAX:           1433 [pixels]
Y_MAX:           1522 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00361831000msufc0137.fits
SUN_POSTN:       163.08d {+10h 52m 20s}   +7.19d {+07d 11' 19"}
SUN_DIST:        103.21 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.75d {+22h 22m 59s}   -7.00d {-06d 59' 58"}
MOON_DIST:        70.23 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:31:27 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.189d {+17h 36m 45s} (J2000)
POINT_DEC:       -25.216d {-25d 12' 56"} (J2000)
POINT_ROLL:      271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5195.59 SOD {01:26:35.59} UT,   137.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.572
N_STARS:         56
X_OFFSET:        474 [pixels]
Y_OFFSET:        563 [pixels]
X_MAX:           1433 [pixels]
Y_MAX:           1522 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00361831000msufc0137.fits
SUN_POSTN:       163.08d {+10h 52m 20s}   +7.19d {+07d 11' 19"}
SUN_DIST:        103.21 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.75d {+22h 23m 00s}   -7.00d {-06d 59' 52"}
MOON_DIST:        70.24 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [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:     Fri 04 Sep 09 01:32:11 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.189d {+17h 36m 45s} (J2000)
POINT_DEC:       -25.216d {-25d 12' 56"} (J2000)
ROLL:            271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5195.59 SOD {01:26:35.59} UT,   137.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     273720400
X_OFFSET:        793 [pixels]
Y_OFFSET:        882 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       953
Y_GRB_POS:       1042
BINNING_INDEX:   1
IM_URL:          sw00361831000msuni0143.fits
SUN_POSTN:       163.08d {+10h 52m 20s}   +7.19d {+07d 11' 18"}
SUN_DIST:        103.21 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.75d {+22h 23m 01s}   -7.00d {-06d 59' 42"}
MOON_DIST:        70.24 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [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:     Fri 04 Sep 09 01:32:40 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.189d {+17h 36m 45s} (J2000)
POINT_DEC:       -25.216d {-25d 12' 56"} (J2000)
ROLL:            271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5195.59 SOD {01:26:35.59} UT,   137.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     273720400
X_OFFSET:        793 [pixels]
Y_OFFSET:        882 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       953
Y_GRB_POS:       1042
BINNING_INDEX:   1
IM_URL:          sw00361831000msuni0143.fits
SUN_POSTN:       163.09d {+10h 52m 20s}   +7.19d {+07d 11' 18"}
SUN_DIST:        103.21 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.76d {+22h 23m 02s}   -6.99d {-06d 59' 36"}
MOON_DIST:        70.25 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [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:     Fri 04 Sep 09 01:30:58 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.189d {+17h 36m 45s} (J2000)
POINT_DEC:       -25.216d {-25d 12' 56"} (J2000)
POINT_ROLL:      271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5195.59 SOD {01:26:35.59} UT,   137.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.572
N_STARS:         56
X_OFFSET:        474 [pixels]
Y_OFFSET:        563 [pixels]
X_MAX:           1433 [pixels]
Y_MAX:           1522 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00361831000msufc0137.fits
SUN_POSTN:       163.08d {+10h 52m 20s}   +7.19d {+07d 11' 19"}
SUN_DIST:        103.21 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.75d {+22h 22m 59s}   -7.00d {-06d 59' 58"}
MOON_DIST:        70.23 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:36:22 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.190d {+17h 36m 46s} (J2000)
POINT_DEC:       -25.213d {-25d 12' 46"} (J2000)
POINT_ROLL:      271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5353.54 SOD {01:29:13.54} UT,   295.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.268
N_STARS:         16
X_OFFSET:        234 [pixels]
Y_OFFSET:        323 [pixels]
X_MAX:           1673 [pixels]
Y_MAX:           1762 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00361831000msufc0295.fits
SUN_POSTN:       163.09d {+10h 52m 21s}   +7.19d {+07d 11' 14"}
SUN_DIST:        103.21 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.79d {+22h 23m 09s}   -6.98d {-06d 58' 47"}
MOON_DIST:        70.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:36:53 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.190d {+17h 36m 46s} (J2000)
POINT_DEC:       -25.213d {-25d 12' 46"} (J2000)
POINT_ROLL:      271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5353.54 SOD {01:29:13.54} UT,   295.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.268
N_STARS:         16
X_OFFSET:        234 [pixels]
Y_OFFSET:        323 [pixels]
X_MAX:           1673 [pixels]
Y_MAX:           1762 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00361831000msufc0295.fits
SUN_POSTN:       163.09d {+10h 52m 21s}   +7.19d {+07d 11' 14"}
SUN_DIST:        103.21 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.79d {+22h 23m 10s}   -6.98d {-06d 58' 40"}
MOON_DIST:        70.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [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:     Fri 04 Sep 09 01:36:22 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.190d {+17h 36m 46s} (J2000)
POINT_DEC:       -25.213d {-25d 12' 46"} (J2000)
POINT_ROLL:      271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5353.54 SOD {01:29:13.54} UT,   295.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.268
N_STARS:         16
X_OFFSET:        234 [pixels]
Y_OFFSET:        323 [pixels]
X_MAX:           1673 [pixels]
Y_MAX:           1762 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00361831000msufc0295.fits
SUN_POSTN:       163.09d {+10h 52m 21s}   +7.19d {+07d 11' 14"}
SUN_DIST:        103.21 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.79d {+22h 23m 09s}   -6.98d {-06d 58' 47"}
MOON_DIST:        70.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:37:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.190d {+17h 36m 46s} (J2000)
POINT_DEC:       -25.213d {-25d 12' 46"} (J2000)
ROLL:            271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5353.54 SOD {01:29:13.54} UT,   295.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     273720558
X_OFFSET:        793 [pixels]
Y_OFFSET:        882 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       953
Y_GRB_POS:       1042
BINNING_INDEX:   1
IM_URL:          sw00361831000msuni0301.fits
SUN_POSTN:       163.09d {+10h 52m 21s}   +7.19d {+07d 11' 13"}
SUN_DIST:        103.20 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.80d {+22h 23m 11s}   -6.97d {-06d 58' 29"}
MOON_DIST:        70.29 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [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:     Fri 04 Sep 09 01:38:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.190d {+17h 36m 46s} (J2000)
POINT_DEC:       -25.213d {-25d 12' 46"} (J2000)
ROLL:            271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5353.54 SOD {01:29:13.54} UT,   295.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     273720558
X_OFFSET:        793 [pixels]
Y_OFFSET:        882 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       953
Y_GRB_POS:       1042
BINNING_INDEX:   1
IM_URL:          sw00361831000msuni0301.fits
SUN_POSTN:       163.09d {+10h 52m 21s}   +7.19d {+07d 11' 13"}
SUN_DIST:        103.20 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.80d {+22h 23m 12s}   -6.97d {-06d 58' 25"}
MOON_DIST:        70.29 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [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:     Fri 04 Sep 09 01:42:45 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     361831,   Seg_Num: 0
GRB_RA:          264.1854d {+17h 36m 44.49s} (J2000),
                 264.3346d {+17h 37m 20.30s} (current),
                 263.4146d {+17h 33m 39.51s} (1950)
GRB_DEC:         -25.2137d {-25d 12' 49.3"} (J2000),
                 -25.2191d {-25d 13' 08.7"} (current),
                 -25.1836d {-25d 11' 01.0"} (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:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5219.00 SOD {01:26:59.00} UT,   160.9 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       163.09d {+10h 52m 22s}   +7.19d {+07d 11' 08"}
SUN_DIST:        103.20 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.84d {+22h 23m 21s}   -6.96d {-06d 57' 23"}
MOON_DIST:        70.33 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the burst
ECL_COORDS:      264.74, -1.88 [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.  
COMMENTS:        This position was enhanced using UVOT field astrometry

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:44:32 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.191d {+17h 36m 46s} (J2000)
POINT_DEC:       -25.213d {-25d 12' 46"} (J2000)
POINT_ROLL:      271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5923.21 SOD {01:38:43.21} UT,   865.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.169
N_STARS:         159
X_OFFSET:        234 [pixels]
Y_OFFSET:        323 [pixels]
X_MAX:           1673 [pixels]
Y_MAX:           1762 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00361831000msufc0865.fits
SUN_POSTN:       163.09d {+10h 52m 22s}   +7.19d {+07d 11' 07"}
SUN_DIST:        103.20 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.85d {+22h 23m 24s}   -6.95d {-06d 57' 00"}
MOON_DIST:        70.34 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:44:32 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.191d {+17h 36m 46s} (J2000)
POINT_DEC:       -25.213d {-25d 12' 46"} (J2000)
POINT_ROLL:      271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5923.21 SOD {01:38:43.21} UT,   865.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.169
N_STARS:         159
X_OFFSET:        234 [pixels]
Y_OFFSET:        323 [pixels]
X_MAX:           1673 [pixels]
Y_MAX:           1762 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00361831000msufc0865.fits
SUN_POSTN:       163.09d {+10h 52m 22s}   +7.19d {+07d 11' 07"}
SUN_DIST:        103.20 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.85d {+22h 23m 24s}   -6.95d {-06d 57' 00"}
MOON_DIST:        70.34 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 Sep 09 01:45:12 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.191d {+17h 36m 46s} (J2000)
POINT_DEC:       -25.213d {-25d 12' 46"} (J2000)
POINT_ROLL:      271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5923.21 SOD {01:38:43.21} UT,   865.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.169
N_STARS:         159
X_OFFSET:        234 [pixels]
Y_OFFSET:        323 [pixels]
X_MAX:           1673 [pixels]
Y_MAX:           1762 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00361831000msufc0865.fits
SUN_POSTN:       163.09d {+10h 52m 22s}   +7.19d {+07d 11' 06"}
SUN_DIST:        103.20 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.86d {+22h 23m 25s}   -6.95d {-06d 56' 51"}
MOON_DIST:        70.35 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [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:     Fri 04 Sep 09 01:46:22 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.191d {+17h 36m 46s} (J2000)
POINT_DEC:       -25.213d {-25d 12' 46"} (J2000)
ROLL:            271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5923.21 SOD {01:38:43.21} UT,   865.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     273721128
X_OFFSET:        793 [pixels]
Y_OFFSET:        882 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       953
Y_GRB_POS:       1042
BINNING_INDEX:   1
IM_URL:          sw00361831000msuni0871.fits
SUN_POSTN:       163.09d {+10h 52m 23s}   +7.18d {+07d 11' 05"}
SUN_DIST:        103.20 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.86d {+22h 23m 27s}   -6.94d {-06d 56' 35"}
MOON_DIST:        70.36 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [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:     Fri 04 Sep 09 01:46:47 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     361831,   Seg_Num: 0
POINT_RA:        264.191d {+17h 36m 46s} (J2000)
POINT_DEC:       -25.213d {-25d 12' 46"} (J2000)
ROLL:            271.860d
IMG_START_DATE:  15078 TJD;   247 DOY;   09/09/04
IMG_START_TIME:  5923.21 SOD {01:38:43.21} UT,   865.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     273721128
X_OFFSET:        793 [pixels]
Y_OFFSET:        882 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       953
Y_GRB_POS:       1042
BINNING_INDEX:   1
IM_URL:          sw00361831000msuni0871.fits
SUN_POSTN:       163.09d {+10h 52m 23s}   +7.18d {+07d 11' 05"}
SUN_DIST:        103.20 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:      335.87d {+22h 23m 28s}   -6.94d {-06d 56' 30"}
MOON_DIST:        70.36 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:        2.12,  3.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      264.74, -1.88 [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 #9881
V. D'Elia (ASDC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), C. Pagani (PSU), M. Perri (ASDC), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), M. A. Stark (PSU) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:
At 01:24:18 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090904B (trigger=361831). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 264.191, -25.212 which is
```
   RA(J2000)  =  17h 36m 46s
   Dec(J2000) = -25d 12' 43"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple overlapping peaks starting at T-5 sec with a duration of about 60 sec. The peak count rate was ~1800 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 01:26:32.3 UT, 134.2 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 264.1854, -25.2138 which is equivalent to:
```
   RA(J2000)  = 17h 36m 44.50s
   Dec(J2000) = -25d 12' 49.7"
```
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This location is 19 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 (3.28e+21 cm^-2, Kalberla et al. 2005), with an excess column of 4.8 (+5.33/-4.01) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 137 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 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. Because of the density of catalogued stars,further analysis is required to report an upper limit for any afterglow in the region.
We note that this is a separate burst from the "A" burst. But there may be some confusion resulting from overlapping GCN Notices.
Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular #9882
S. Covino, L.A. Antonelli, P. D'Avanzo, D. Fugazza, S. Campana, G. Chincarini, V. D'Elia, F. D'Alessio, F. Fiore, P. Goldoni, C. Guidorzi, E. Maiorano, L. Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella, G. Tagliaferri, G. Tosti, V. Testa, S.D. Vergani, F. Vitali report on behalf of the REM team:
The REM 60-cm robotic telescope located at ESO-La Silla reacted promptly after the Swift alert for GRB09094B. Observations began 108 seconds after the GRB time (40 s after the trigger) with the R and H bands and continued with all the available filters (VRIJHK). No transient was singled out in the images, although a not varying 2MASS star with H=11.95 seems to be coincident with the XRT position. The field is located very close to the Galactic Center (LII = 2.12 deg, BII = 3.64 deg) and is heavily reddened and crowded, requiring further analyses to evaluate the chance for this positional coincidence.
Further observations are in progress.
GCN Circular #9887
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1190 s of XRT Photon Counting mode data and 1 UVOT images for GRB 090904B, 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 = 264.18534, -25.21305 which is equivalent to:
```
RA (J2000): 17h 36m 44.48s
Dec (J2000): -25d 12' 47.0"
```
with an uncertainty of 1.8 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #9890
T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-119 to T+303 sec from the recent telemetry downlink, we report further analysis of BAT GRB 090904B (trigger #361831) (D'Elia, et al., GCN Circ. 9881). The BAT ground-calculated position is RA, Dec = 264.194, -25.219 deg, which is
```
   RA(J2000)  =  17h 36m 46.5s 
   Dec(J2000) = -25d 13' 09.0" 
```
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 8%.
The mask-weighted light curve shows the burst starting at ~T-30 sec, with several overlapping peaks between T-5 to T+20 sec and another series from T+30 to T+50 sec. The burst is over by ~T+70 sec T90 (15-350 keV) is 47.0 +- 1.7 sec (estimated error including systematics).
The time-averaged spectrum from T-2.5 to T+49.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.59 +- 0.07. The fluence in the 15-150 keV band is 1.1 +- 0.0 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+12.42 sec in the 15-150 keV band is 5.3 +- 0.9 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/361831/BA/
GCN Circular #9892
K. Nishimoto, T. Sako, and D. Suzuki (STE Lab, Nagoya Univ.) on behalf of the MOA Collaboration report:
We searched for an optical afterglow of GRB090904B (GCN9881, V. D'Elia et al.) starting from 07:34:56.9 UT on 2009 Sep 4 (6 hours after the burst) with the MOA-II 1.8m telescope at Mt.John observatory in New Zealand. In a single image of a 60 sec 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 9887), except a USNO-B1.0 catalog star, 0647-0516939, which has I mag=15.10 and the separation of 1.8 arcsec from the center of the position.
Quick estimation of the limiting magnitude is >20.5 calibrated by using USNO-B1.0 catalog.
GCN Circular #9893
V. D'Elia, G. Stratta, M. Perri (ASDC) report on behalf of the Swift-XRT team:
We have analysed 6.2 ks of XRT data for GRB 090904B (D'Elia et al. GCN Circ. 9881), from 159 s to 37.1 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 9987).
The light curve, after an initial rise, peaks at T+260 s, while the following decay can be modelled with a power-law with a decay index of alpha=1.20+-0.05 (90% confidence level).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.67 (+0.26, -0.24, 90% confidence level). The best-fitting absorption column is 6.3 (+2.5, -1.1) x 1021 cm-2, in excess with respect to the Galactic value of 3.3 x 1021 cm-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 6.8 x 10-11 (1.1 x 10-10) erg cm-2 count-1.
If the light curve continues to decay with a power-law decay index of 1.20, the count rate at T+24 hours will be 0.0040 count s-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.7 x 10-13 (4.4 x 10-13) erg cm-2 s-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00361831.
This circular is an official product of the Swift-XRT team.
GCN Circular #9895
A. Goldstein (UAH) reports on behalf of the Fermi GBM Team:
"At 01:24:13.93 UT on 04 September 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090904B (trigger 273720255 / 090904058), which was also detected by the SWIFT-BAT (D'Elia et al. 2009, GCN 9881). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 113 degrees.
The GBM light curve consists of three bright peaks with a duration (T90) of about 71 s (8-1000 keV). The time-averaged spectrum from T0-9.2 s to T0+65.5 s is well fit by a power law function with an exponential high energy cutoff. The power law index is 1.41 +/- 0.08 and the cutoff energy, parameterized as Epeak, is 149.30 +/- 22.10 keV (chi squared 243.6 for 238 d.o.f.).
The event fluence (8-1000 keV) in this time interval is (2.44 +/- 0.15)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+21.5 s in the 8-1000 keV band is 9.8 +/- 0.7 ph/s/cm^2.
A Band function fits the spectrum equally well (chi squared 239.0 for 237 d.o.f.) with Epeak= 106.30 +/- 24.60 keV, alpha = -1.26 +/- 0.15 and beta = -2.18 +/- 0.18.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #9898
T. A. Pritchard (PSU) and D'Elia (ASDC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 090904B, 138 seconds after the BAT trigger (D'Elia et al., GCN Circ. 9881). We do not detect any source at the UVOT-enhanced XRT position (J.P. Osbourne et al., GCN Circ.9887).
The 3-sigma upper limits for the exposures are:
```
Filter   T_start(s)   T_stop(s)   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white      138          1357       369      > 22.17
v          625          1237        78      > 19.08
b          551           1335        78      > 20.08
u          295            545       246      > 20.41
-------------------------------------------------------------
```
The quoted upper limits have not been corrected for the highly uncertain extinction corresponding to a reddening along the line of sight of of E_(B-V) = 1.76 mag Schlegel et al., (1998, ApJS, 500, 525). All photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular #9901
F. Olivares, P. Afonso, T. Kruehler, J. Greiner (all MPE Garching), report on behalf of the GROND team:
The field of GRB 090904B (Swift trigger 361831, D'Elia et al., GCN #9881, also GBM trigger 273720255/090904058, Goldstein, GCN #9895) was observed 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 01:28 UT, on September 4, 2009, 4 minutes after the GRB trigger. The field was observed during a second epoch, starting at 01:28 UT, on September 5, 2009, 24.07 hours after the GRB trigger. Image subtraction between the two epochs reveals a fading source on the edge of the enhanced Swift/XRT error circle (Osborne et al., GCN #9887). The position of the afterglow is
```
RA (J2000.0) = 17h 36m 44.59s
DEC (J2000.0) = -25d 12' 46.5"
```
with an uncertainty of 0.5" in each coordinate.
The afterglow is located roughly 1.1" South/East of the 2MASS/USNO star reported by REM (Covino et al., GCN #9882) and MOA-II (Nishimoto et al., GCN #9892), and both sources are strongly blended in the GROND images of 1.0" seeing.
At a midtime of 6.5 minutes after the burst, we measure rough preliminary AB magnitudes of the optical afterglow of r' ~ 22.2, i ~ 20.6 and z' ~ 19.7.
Calibrations were done against GROND zero points, and given magnitudes are not corrected for the significant Galactic extinction corresponding to a reddening of E(B-V) = 1.76 mag (Schlegel et al. 1998). The object is detected in all bands except g', which, given the large Galactic foreground extinction, does not constrain the redshift.
GCN Report 242.1
GCN_Report 242.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_242_1.pdf by V. D Elia at ASDC titled: "Final Results on Swift GRB 090904B"
GCN Circular #9931
K. Nishimoto, T. Sako(Nagoya Univ.) on behalf of the MOA Collaboration, M. Kurita on behalf of the IRSF Collabration, T. Yosikawa(Kyoto Univ.), T. Suenaga(Soken Univ.) report:
We searched for a NIR afterglow of GRB090904B (GCN9881, V. D'Elia et al.) starting from 17:6:57.7 UT on 2009 Sep 4 (15.71 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 except the reported star (GCN9882, Covino et al and GCN9892, Nishimoto et al.) within the error circle of the Swift XRT source position (GCN9887, J.P. Osborne et al.).
Quick estimation of the limiting magnitude calibrated by using 2MASS catalog:
```
J > 17.14
H > 16.57
K > 15.79
```

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Jochen Greiner, last update: 25-Sep-2009 [Disclaimer]