Gamma-ray Burst 090831C

(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 31 Aug 09 21:31:25 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     361489,   Seg_Num: 0
GRB_RA:          108.278d {+07h 13m 07s} (J2000),
                 108.378d {+07h 13m 31s} (current),
                 107.762d {+07h 11m 03s} (1950)
GRB_DEC:         -25.100d {-25d 06' 00"} (J2000),
                 -25.117d {-25d 07' 00"} (current),
                 -25.014d {-25d 00' 49"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       19836 [cnts]    Image_Peak=460 [image_cnts]
TRIGGER_DUR:     5.504 [sec] 
TRIGGER_INDEX:   476     E_range: 25-100 keV
BKG_INTEN:       159379 [cnts]
BKG_TIME:        77354.95 SOD {21:29:14.95} UT
BKG_DUR:         48 [sec]
GRB_DATE:        15074 TJD;   243 DOY;   09/08/31
GRB_TIME:        77425.92 SOD {21:30:25.92} UT
GRB_PHI:         -39.37 [deg]
GRB_THETA:        23.37 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.00 [sigma]
IMAGE_SIGNIF:    8.36 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +2  -1  +0  +1 -48  +0 
SUN_POSTN:       160.22d {+10h 40m 53s}   +8.35d {+08d 20' 45"}
SUN_DIST:         60.54 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.17d {+19h 56m 41s}  -21.07d {-21d 04' 21"}
MOON_DIST:       132.64 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      237.73, -6.74 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      114.61,-46.99 [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 = 167.98,19.47 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:32:31 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.289d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 25"} (J2000)
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77543.46 SOD {21:32:23.46} UT,   117.5 [sec] since BAT Trigger Time
COUNTS:          3    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:34:21 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     361489,   Seg_Num: 0
GRB_RA:          108.278d {+07h 13m 07s} (J2000),
                 108.378d {+07h 13m 31s} (current),
                 107.762d {+07h 11m 03s} (1950)
GRB_DEC:         -25.100d {-25d 06' 00"} (J2000),
                 -25.117d {-25d 07' 00"} (current),
                 -25.014d {-25d 00' 49"} (1950)
GRB_DATE:        15074 TJD;   243 DOY;   09/08/31
GRB_TIME:        77425.92 SOD {21:30:25.92} UT
TRIGGER_INDEX:   476
GRB_PHI:         -39.37 [deg]
GRB_THETA:        23.37 [deg]
DELTA_TIME:      -56.00 [sec]
TRIGGER_DUR:     5.504 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.00 [sigma]
IMAGE_SIGNIF:    8.36 [sigma]
LC_URL:          sw00361489000msb.lc
SUN_POSTN:       160.22d {+10h 40m 53s}   +8.35d {+08d 20' 43"}
SUN_DIST:         60.54 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.20d {+19h 56m 47s}  -21.07d {-21d 03' 56"}
MOON_DIST:       132.64 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      237.73, -6.74 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      114.61,-46.99 [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 = 167.98,19.47 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:36:01 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     361489,   Seg_Num: 0
GRB_RA:          108.2930d {+07h 13m 10.32s} (J2000),
                 108.3929d {+07h 13m 34.29s} (current),
                 107.7764d {+07h 11m 06.32s} (1950)
GRB_DEC:         -25.1192d {-25d 07' 09.1"} (J2000),
                 -25.1361d {-25d 08' 10.0"} (current),
                 -25.0330d {-25d 01' 58.8"} (1950)
GRB_ERROR:       3.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77557.00 SOD {21:32:37.00} UT,   131.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       160.22d {+10h 40m 53s}   +8.34d {+08d 20' 41"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.21d {+19h 56m 50s}  -21.06d {-21d 03' 42"}
MOON_DIST:       132.62 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      237.75, -6.73 [deg] galactic lon,lat of the burst
ECL_COORDS:      114.63,-47.01 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:36:31 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.289d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 24"} (J2000)
POINT_ROLL:      63.386d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77546.72 SOD {21:32:26.72} UT,   120.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.064
N_STARS:         190
X_OFFSET:        427 [pixels]
Y_OFFSET:        631 [pixels]
X_MAX:           1386 [pixels]
Y_MAX:           1590 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00361489000msufc0120.fits
SUN_POSTN:       160.22d {+10h 40m 53s}   +8.34d {+08d 20' 41"}
SUN_DIST:         60.52 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.21d {+19h 56m 51s}  -21.06d {-21d 03' 38"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      237.73, -6.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.62,-46.98 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:36:31 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.289d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 24"} (J2000)
POINT_ROLL:      63.386d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77546.72 SOD {21:32:26.72} UT,   120.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.064
N_STARS:         190
X_OFFSET:        427 [pixels]
Y_OFFSET:        631 [pixels]
X_MAX:           1386 [pixels]
Y_MAX:           1590 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00361489000msufc0120.fits
SUN_POSTN:       160.22d {+10h 40m 53s}   +8.34d {+08d 20' 41"}
SUN_DIST:         60.52 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.21d {+19h 56m 51s}  -21.06d {-21d 03' 38"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      237.73, -6.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.62,-46.98 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:37:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.289d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 24"} (J2000)
POINT_ROLL:      63.386d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77546.72 SOD {21:32:26.72} UT,   120.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.064
N_STARS:         190
X_OFFSET:        427 [pixels]
Y_OFFSET:        631 [pixels]
X_MAX:           1386 [pixels]
Y_MAX:           1590 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00361489000msufc0120.fits
SUN_POSTN:       160.22d {+10h 40m 53s}   +8.34d {+08d 20' 40"}
SUN_DIST:         60.52 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.22d {+19h 56m 53s}  -21.06d {-21d 03' 32"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      237.73, -6.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.62,-46.98 [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 31 Aug 09 21:38:37 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.289d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 24"} (J2000)
ROLL:            63.386d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77546.72 SOD {21:32:26.72} UT,   120.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     273447151
X_OFFSET:        746 [pixels]
Y_OFFSET:        950 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       906
Y_GRB_POS:       1110
BINNING_INDEX:   1
IM_URL:          sw00361489000msuni0126.fits
SUN_POSTN:       160.22d {+10h 40m 54s}   +8.34d {+08d 20' 39"}
SUN_DIST:         60.52 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.23d {+19h 56m 56s}  -21.06d {-21d 03' 21"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      237.73, -6.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.62,-46.98 [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 31 Aug 09 21:39:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.289d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 24"} (J2000)
ROLL:            63.386d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77546.72 SOD {21:32:26.72} UT,   120.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     273447151
X_OFFSET:        746 [pixels]
Y_OFFSET:        950 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       906
Y_GRB_POS:       1110
BINNING_INDEX:   1
IM_URL:          sw00361489000msuni0126.fits
SUN_POSTN:       160.22d {+10h 40m 54s}   +8.34d {+08d 20' 39"}
SUN_DIST:         60.52 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.24d {+19h 56m 57s}  -21.05d {-21d 03' 17"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      237.73, -6.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.62,-46.98 [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 #9854
P. Schady (MSSL-UCL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), A. Rowlinson (U Leicester), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC) and M. A. Stark (PSU) report on behalf of the Swift Team:
At 21:30:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090831C (trigger=361489). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 108.278, -25.100 which is
```
   RA(J2000)  =  07h 13m 07s
   Dec(J2000) = -25d 06' 00"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 10 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 21:32:23.5 UT, 117.5 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 108.29307, -25.11934 which is equivalent to:
```
   RA(J2000)  = 07h 13m 10.34s
   Dec(J2000) = -25d 07' 09.6"
```
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This location is 85 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 3.24e+21 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 120 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. Results from the 2.7'x2.7' sub-image are not available at this time. The coverage of the XRT error circle by the 8'x8' region for the list of sources generated on-board is uncertain because the large number of sources filled the available telemetry. No correction has been made for the expected extinction corresponding to E(B-V) of 0.38.
Burst Advocate for this burst is P. Schady (ps AT mssl.ucl.ac.uk). 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 31 Aug 09 21:44:22 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.286d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 22"} (J2000)
POINT_ROLL:      63.389d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77704.94 SOD {21:35:04.94} UT,   279.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        2.026
N_STARS:         190
X_OFFSET:        187 [pixels]
Y_OFFSET:        391 [pixels]
X_MAX:           1626 [pixels]
Y_MAX:           1830 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00361489000msufc0279.fits
SUN_POSTN:       160.23d {+10h 40m 55s}   +8.34d {+08d 20' 34"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.28d {+19h 57m 07s}  -21.04d {-21d 02' 33"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.72, -6.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.61,-46.98 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:44:22 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.286d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 22"} (J2000)
POINT_ROLL:      63.389d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77704.94 SOD {21:35:04.94} UT,   279.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        2.026
N_STARS:         190
X_OFFSET:        187 [pixels]
Y_OFFSET:        391 [pixels]
X_MAX:           1626 [pixels]
Y_MAX:           1830 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00361489000msufc0279.fits
SUN_POSTN:       160.23d {+10h 40m 55s}   +8.34d {+08d 20' 34"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.28d {+19h 57m 07s}  -21.04d {-21d 02' 33"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.72, -6.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.61,-46.98 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:45:15 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.286d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 22"} (J2000)
POINT_ROLL:      63.389d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77704.94 SOD {21:35:04.94} UT,   279.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        2.026
N_STARS:         190
X_OFFSET:        187 [pixels]
Y_OFFSET:        391 [pixels]
X_MAX:           1626 [pixels]
Y_MAX:           1830 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00361489000msufc0279.fits
SUN_POSTN:       160.23d {+10h 40m 55s}   +8.34d {+08d 20' 33"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.29d {+19h 57m 09s}  -21.04d {-21d 02' 26"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.72, -6.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.61,-46.98 [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 31 Aug 09 21:45:48 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.286d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 22"} (J2000)
ROLL:            63.389d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77704.94 SOD {21:35:04.94} UT,   279.0 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     273447309
X_OFFSET:        746 [pixels]
Y_OFFSET:        950 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       906
Y_GRB_POS:       1110
BINNING_INDEX:   1
IM_URL:          sw00361489000msuni0285.fits
SUN_POSTN:       160.23d {+10h 40m 55s}   +8.34d {+08d 20' 32"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.29d {+19h 57m 10s}  -21.04d {-21d 02' 21"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.72, -6.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.61,-46.98 [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 31 Aug 09 21:45:58 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     361489,   Seg_Num: 0
GRB_RA:          108.2943d {+07h 13m 10.63s} (J2000),
                 108.3942d {+07h 13m 34.60s} (current),
                 107.7776d {+07h 11m 06.63s} (1950)
GRB_DEC:         -25.1185d {-25d 07' 06.6"} (J2000),
                 -25.1354d {-25d 08' 07.5"} (current),
                 -25.0323d {-25d 01' 56.2"} (1950)
GRB_ERROR:       2.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77557.00 SOD {21:32:37.00} UT,   131.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       160.23d {+10h 40m 55s}   +8.34d {+08d 20' 32"}
SUN_DIST:         60.54 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.29d {+19h 57m 11s}  -21.04d {-21d 02' 20"}
MOON_DIST:       132.63 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.75, -6.73 [deg] galactic lon,lat of the burst
ECL_COORDS:      114.63,-47.01 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:46:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.286d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 22"} (J2000)
ROLL:            63.389d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  77704.94 SOD {21:35:04.94} UT,   279.0 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     273447309
X_OFFSET:        746 [pixels]
Y_OFFSET:        950 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       906
Y_GRB_POS:       1110
BINNING_INDEX:   1
IM_URL:          sw00361489000msuni0285.fits
SUN_POSTN:       160.23d {+10h 40m 55s}   +8.34d {+08d 20' 32"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.30d {+19h 57m 11s}  -21.04d {-21d 02' 17"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.72, -6.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.61,-46.98 [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:     Mon 31 Aug 09 21:50:32 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.286d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 22"} (J2000)
POINT_ROLL:      63.389d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  78285.56 SOD {21:44:45.56} UT,   859.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        7.101
N_STARS:         190
X_OFFSET:        187 [pixels]
Y_OFFSET:        391 [pixels]
X_MAX:           1626 [pixels]
Y_MAX:           1830 [pixels]
DET_THRESH:      23
PHOTO_THRESH:    14
SL_URL:          sw00361489000msufc0859.fits
SUN_POSTN:       160.23d {+10h 40m 55s}   +8.34d {+08d 20' 28"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.33d {+19h 57m 20s}  -21.03d {-21d 01' 42"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.72, -6.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.61,-46.98 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:50:32 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.286d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 22"} (J2000)
POINT_ROLL:      63.389d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  78285.56 SOD {21:44:45.56} UT,   859.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        7.101
N_STARS:         190
X_OFFSET:        187 [pixels]
Y_OFFSET:        391 [pixels]
X_MAX:           1626 [pixels]
Y_MAX:           1830 [pixels]
DET_THRESH:      23
PHOTO_THRESH:    14
SL_URL:          sw00361489000msufc0859.fits
SUN_POSTN:       160.23d {+10h 40m 55s}   +8.34d {+08d 20' 28"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.33d {+19h 57m 20s}  -21.03d {-21d 01' 42"}
MOON_DIST:       132.65 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.72, -6.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.61,-46.98 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 31 Aug 09 21:51:11 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.286d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 22"} (J2000)
POINT_ROLL:      63.389d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  78285.56 SOD {21:44:45.56} UT,   859.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        7.101
N_STARS:         190
X_OFFSET:        187 [pixels]
Y_OFFSET:        391 [pixels]
X_MAX:           1626 [pixels]
Y_MAX:           1830 [pixels]
DET_THRESH:      23
PHOTO_THRESH:    14
SL_URL:          sw00361489000msufc0859.fits
SUN_POSTN:       160.23d {+10h 40m 56s}   +8.34d {+08d 20' 28"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.34d {+19h 57m 21s}  -21.03d {-21d 01' 36"}
MOON_DIST:       132.66 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.72, -6.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.61,-46.98 [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 31 Aug 09 21:52:09 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.286d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 22"} (J2000)
ROLL:            63.389d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  78285.56 SOD {21:44:45.56} UT,   859.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     273447890
X_OFFSET:        746 [pixels]
Y_OFFSET:        950 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       906
Y_GRB_POS:       1110
BINNING_INDEX:   1
IM_URL:          sw00361489000msuni0865.fits
SUN_POSTN:       160.23d {+10h 40m 56s}   +8.34d {+08d 20' 27"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.35d {+19h 57m 23s}  -21.02d {-21d 01' 28"}
MOON_DIST:       132.66 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.72, -6.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.61,-46.98 [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 31 Aug 09 21:52:33 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     361489,   Seg_Num: 0
POINT_RA:        108.286d {+07h 13m 09s} (J2000)
POINT_DEC:       -25.090d {-25d 05' 22"} (J2000)
ROLL:            63.389d
IMG_START_DATE:  15074 TJD;   243 DOY;   09/08/31
IMG_START_TIME:  78285.56 SOD {21:44:45.56} UT,   859.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     273447890
X_OFFSET:        746 [pixels]
Y_OFFSET:        950 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       906
Y_GRB_POS:       1110
BINNING_INDEX:   1
IM_URL:          sw00361489000msuni0865.fits
SUN_POSTN:       160.23d {+10h 40m 56s}   +8.34d {+08d 20' 26"}
SUN_DIST:         60.53 [deg]   Sun_angle= 3.5 [hr] (West of Sun)
MOON_POSTN:      299.35d {+19h 57m 24s}  -21.02d {-21d 01' 25"}
MOON_DIST:       132.66 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      237.72, -6.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      114.61,-46.98 [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 #9855
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 3607 s of XRT Photon Counting mode data and 3 UVOT images for GRB 090831C, 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 = 108.29453, -25.11859 which is equivalent to:
```
RA (J2000): 07h 13m 10.69s
Dec (J2000): -25d 07' 06.9"
```
with an uncertainty of 1.8 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, arXiv:0812.3662).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #9857
A. Rowlinson (U. Leicester) and P. Schady (MSSL-UCL) report on behalf of the Swift-XRT team:
We have analysed 8.4 ks of XRT data for GRB 090831C (Schady et al. GCN Circ. 9854), from 121 s to 21.8 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN. Circ 9855).
The light curve has two flares at T+186 s and T+440 s, while the underlying decay can be modelled with a power-law decay with a decay index of alpha=0.83 (+0.17, -0.11).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.84 (+0.21, -0.15). The best-fitting absorption column is 3.254 (+1.001, -0.014) x 10^21 cm^-2, consistent with the Galactic value of 3.2 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 4.9 x 10^-11 (7.2 x 10^-11) erg cm^-2 count^-1.
If the light curve continues to decay with a power-law decay index of 0.83, the count rate at T+24 hours will be 0.0029 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.4 x 10^-13 (2.1 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/00361489.
This circular is an official product of the Swift-XRT team.
GCN Circular #9859
P. Schady (MSSL-UCL) reports on behalf of the Swift/UVOT team.
The Swift/UVOT began settled observations of the field of GRB 090831C 121s after the BAT trigger (Schady et al., GCN Circ 9854). No new source is detected within the XRT error circle (Evans et al., GCN Circ 9855) in any of the individual or combined UVOT filters.
The 3-sigma upper limits of detecting a source at the position of the X-ray afterglow in the first white band finding chart (fc) observation and in consecutive coadded observations for each of the UVOT filters are as follows:
```
Filter	T_start(s) T_stop(s) Exp(s) Mag 3-sig UL
wh (fc)    121       270     147      > 20.78
wh         561       1183    206      > 20.73
vv         610       1060    58       > 18.47
bb         536       1159    58       > 19.30
uu         279       1134    285      > 19.95
w1         660       1109    58       > 18.74
m2         635       1084    58       > 18.48
w2         586       1209    78       > 18.95
```
The values quoted above are not corrected for the Galactic extinction due to the large reddening of E(B-V) = 0.38 in the direction of the burst (Schlegel et al., 1998). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular #9862
F. Olivares, T. Kruehler and J. Greiner (all MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 090831C (Swift trigger #361489; Schady et al., GCN #9854) 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 LaSilla Observatory (Chile).
Observations started at 08:07 UT on September 1st, 2009, 10.6 hr after the burst. At this time the position of the burst was becoming visible above the pointing constraints of the telescope. Observations suffer from high airmass and large seeing of around 2". In stacked images of 74 min total integration time in griz and 60 min in JHK, we do not detect any object within the enhanced XRT error circle (Evans et al., GCN #9855), down to the following limiting magnitudes (all in the AB system):
```
g' > 23.5
r' > 24.0
i' > 23.3
z' > 22.9
J > 21.4
H > 21.1
K > 20.0
```
These upper limits were derived using the GROND zeropoints and 2MASS field stars as reference and are not corrected for significant Galactic foreground extinction corresponding to a reddening of E(B-V)=0.38 mag (Schlegel et al., 1998).
GCN Circular #9863
C. B. Markwardt (GSFC/UMD), 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), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), P. Schady (MSSL-UCL), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 090831 (trigger #361489) (Schady, et al., GCN Circ. 9854). The BAT ground-calculated position is RA, Dec = 108.294, -25.112 deg which is
```
    RA(J2000)  =  07h 13m 10.6s
    Dec(J2000) = -25d 06' 44.0"
```
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 84%.
The mask-weighted light curve shows a single roughly symmetrical peak. T90 (15-350 keV) is 3.3 +- 1.0 sec (estimated error including systematics).
The time-averaged spectrum from T+0.6 to T+4.9 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.33 +- 0.29. The fluence in the 15-150 keV band is 1.5 +- 0.3 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+1.94 sec in the 15-150 keV band is 0.5 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/361489/BA/
GCN Report 239.1
GCN_Report 239.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_239_1.pdf by P. Schady at MSSL-UCL titled: "Final Results on Swift GRB 090831C"

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Jochen Greiner, last update: 09-Sep-2009 [Disclaimer]