Gamma-ray Burst 101008A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 08 Oct 10 16:43:33 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      47
TRIGGER_NUM:     308248997
GRB_RA:          324.800d {+21h 39m 12s} (J2000),
                 324.915d {+21h 39m 40s} (current),
                 324.268d {+21h 37m 04s} (1950)
GRB_DEC:         +34.033d {+34d 01' 60"} (J2000),
                 +34.082d {+34d 04' 56"} (current),
                 +33.807d {+33d 48' 24"} (1950)
GRB_ERROR:       13.17 [deg radius, statistical plus systematic]
GRB_INTEN:       253 [cnts/sec]
DATA_SIGNIF:     7.60 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        15477 TJD;   281 DOY;   10/10/08
GRB_TIME:        60195.61 SOD {16:43:15.61} UT
GRB_PHI:         235.00 [deg]
GRB_THETA:        75.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      0.57
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      78%  GRB
2nd_MOST_LIKELY:   9%  Cyg X-1
DETECTORS:       0,0,0, 0,0,0, 0,1,1, 0,0,0, 0,0,
SUN_POSTN:       194.08d {+12h 56m 20s}   -6.02d {-06d 01' 17"}
SUN_DIST:        126.68 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      204.18d {+13h 36m 44s}  -15.04d {-15d 02' 23"}
MOON_DIST:       123.65 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       83.54,-13.75 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      342.34, 44.71 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.
COMMENTS:        This trigger occurred at longitude,latitude = 31.20,-22.63 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Oct 10 16:43:37 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     435903,   Seg_Num: 0
GRB_RA:          328.891d {+21h 55m 34s} (J2000),
                 329.005d {+21h 56m 01s} (current),
                 328.359d {+21h 53m 26s} (1950)
GRB_DEC:         +37.062d {+37d 03' 44"} (J2000),
                 +37.114d {+37d 06' 49"} (current),
                 +36.825d {+36d 49' 28"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4778 [cnts]    Image_Peak=267 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       27028 [cnts]
BKG_TIME:        60177.74 SOD {16:42:57.74} UT
BKG_DUR:         8 [sec]
GRB_DATE:        15477 TJD;   281 DOY;   10/10/08
GRB_TIME:        60195.21 SOD {16:43:15.21} UT
GRB_PHI:         -162.71 [deg]
GRB_THETA:        39.66 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     21.16 [sigma]
IMAGE_SIGNIF:    10.70 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +0  +0  +0 +62  +0 
SUN_POSTN:       194.08d {+12h 56m 20s}   -6.02d {-06d 01' 17"}
SUN_DIST:        128.56 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      204.18d {+13h 36m 44s}  -15.04d {-15d 02' 24"}
MOON_DIST:       126.61 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       88.17,-13.67 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      348.54, 45.80 [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 = 130.08,-18.86 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 08 Oct 10 16:43:54 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      59
TRIGGER_NUM:     308248997
GRB_RA:          335.390d {+22h 21m 34s} (J2000),
                 335.513d {+22h 22m 03s} (current),
                 334.818d {+22h 19m 16s} (1950)
GRB_DEC:         +30.360d {+30d 21' 36"} (J2000),
                 +30.415d {+30d 24' 52"} (current),
                 +30.107d {+30d 06' 27"} (1950)
GRB_ERROR:       7.71 [deg radius, statistical only]
DATA_SIGNIF:     9.10 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        15477 TJD;   281 DOY;   10/10/08
GRB_TIME:        60195.61 SOD {16:43:15.61} UT
GRB_PHI:         225.00 [deg]
GRB_THETA:        75.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:       194.08d {+12h 56m 20s}   -6.02d {-06d 01' 17"}
SUN_DIST:        136.35 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      204.19d {+13h 36m 45s}  -15.04d {-15d 02' 28"}
MOON_DIST:       132.95 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       88.37,-22.27 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      350.69, 37.35 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 08 Oct 10 16:44:02 UT
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    6070,   Sub_Num: 0
GRB_INTEN:      9.50 [sigma]
GRB_TIME:       60193.45 SOD {16:43:13.45} UT
GRB_DATE:       15477 TJD;   281 DOY;   10/10/08
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:
COMMENTS:       NOTE: This SPIACS event is temporally(2.0<100sec) coincident with the SWIFT_BAT event (trignum=435903).
COMMENTS:
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2010-10/2010-10-08T16-43-13.2500-13802-00007-0.lc

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Oct 10 16:46:49 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     435903,   Seg_Num: 0
GRB_RA:          328.891d {+21h 55m 34s} (J2000),
                 329.005d {+21h 56m 01s} (current),
                 328.359d {+21h 53m 26s} (1950)
GRB_DEC:         +37.062d {+37d 03' 44"} (J2000),
                 +37.114d {+37d 06' 49"} (current),
                 +36.825d {+36d 49' 28"} (1950)
GRB_DATE:        15477 TJD;   281 DOY;   10/10/08
GRB_TIME:        60195.21 SOD {16:43:15.21} UT
TRIGGER_INDEX:   146
GRB_PHI:         -162.71 [deg]
GRB_THETA:        39.66 [deg]
DELTA_TIME:      12.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     21.16 [sigma]
IMAGE_SIGNIF:    10.70 [sigma]
LC_URL:          sw00435903000msb.lc
SUN_POSTN:       194.09d {+12h 56m 21s}   -6.02d {-06d 01' 20"}
SUN_DIST:        128.56 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      204.22d {+13h 36m 52s}  -15.05d {-15d 03' 04"}
MOON_DIST:       126.59 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       88.17,-13.67 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      348.54, 45.80 [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 = 130.08,-18.86 [deg].

GCN Circular #11318
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC), S. Immler (CRESST/GSFC/UMD), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), C. Pagani (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), A. Rowlinson (U Leicester), B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU), M. C. Stroh (PSU) and E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team:
At 16:43:15 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 101008A (trigger=435903). Swift could not slew to the burst location due to an Earth limb constraint. The BAT on-board calculated location is RA, Dec 328.891, +37.062 which is
```
   RA(J2000) = 21h 55m 34s
   Dec(J2000) = +37d 03' 44"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows many peaks in an overall FRED envelope structure with a duration of about 15 sec. The peak count rate was ~2500 counts/sec (15-350 keV), at ~1 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+50.8 minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is W. H. Baumgartner (wayne AT milkyway.gsfc.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:     Fri 08 Oct 10 17:36:11 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     435903,   Seg_Num: 0
POINT_RA:        328.867d {+21h 55m 28s} (J2000)
POINT_DEC:       +37.066d {+37d 03' 56"} (J2000)
IMG_START_DATE:  15477 TJD;   281 DOY;   10/10/08
IMG_START_TIME:  63356.87 SOD {17:35:56.87} UT,   3161.7 [sec] since BAT Trigger Time
COUNTS:          2    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:     Fri 08 Oct 10 17:40:17 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     435903,   Seg_Num: 0
POINT_RA:        328.866d {+21h 55m 28s} (J2000)
POINT_DEC:       +37.066d {+37d 03' 56"} (J2000)
POINT_ROLL:      295.600d
IMG_START_DATE:  15477 TJD;   281 DOY;   10/10/08
IMG_START_TIME:  63361.96 SOD {17:36:01.96} UT,   3166.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.640
N_STARS:         137
X_OFFSET:        366 [pixels]
Y_OFFSET:        661 [pixels]
X_MAX:           1325 [pixels]
Y_MAX:           1620 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00435903000msufc3166.fits
SUN_POSTN:       194.12d {+12h 56m 29s}   -6.04d {-06d 02' 11"}
SUN_DIST:        128.52 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      204.75d {+13h 39m 00s}  -15.23d {-15d 14' 01"}
MOON_DIST:       126.25 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       88.16,-13.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      348.52, 45.82 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Oct 10 17:40:45 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     435903,   Seg_Num: 0
POINT_RA:        328.866d {+21h 55m 28s} (J2000)
POINT_DEC:       +37.066d {+37d 03' 56"} (J2000)
POINT_ROLL:      295.600d
IMG_START_DATE:  15477 TJD;   281 DOY;   10/10/08
IMG_START_TIME:  63361.96 SOD {17:36:01.96} UT,   3166.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.640
N_STARS:         137
X_OFFSET:        366 [pixels]
Y_OFFSET:        661 [pixels]
X_MAX:           1325 [pixels]
Y_MAX:           1620 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00435903000msufc3166.fits
SUN_POSTN:       194.12d {+12h 56m 29s}   -6.04d {-06d 02' 11"}
SUN_DIST:        128.52 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      204.76d {+13h 39m 01s}  -15.24d {-15d 14' 07"}
MOON_DIST:       126.25 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       88.16,-13.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      348.52, 45.82 [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 08 Oct 10 17:42:09 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     435903,   Seg_Num: 0
POINT_RA:        328.866d {+21h 55m 28s} (J2000)
POINT_DEC:       +37.066d {+37d 03' 56"} (J2000)
ROLL:            295.600d
IMG_START_DATE:  15477 TJD;   281 DOY;   10/10/08
IMG_START_TIME:  63361.96 SOD {17:36:01.96} UT,   3166.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     308252168
X_OFFSET:        685 [pixels]
Y_OFFSET:        980 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       845
Y_GRB_POS:       1140
BINNING_INDEX:   1
IM_URL:          sw00435903000msuni3173.fits
SUN_POSTN:       194.12d {+12h 56m 29s}   -6.04d {-06d 02' 13"}
SUN_DIST:        128.52 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      204.77d {+13h 39m 05s}  -15.24d {-15d 14' 24"}
MOON_DIST:       126.24 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       88.16,-13.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      348.52, 45.82 [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 08 Oct 10 17:42:24 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     435903,   Seg_Num: 0
POINT_RA:        328.866d {+21h 55m 28s} (J2000)
POINT_DEC:       +37.066d {+37d 03' 56"} (J2000)
ROLL:            295.600d
IMG_START_DATE:  15477 TJD;   281 DOY;   10/10/08
IMG_START_TIME:  63361.96 SOD {17:36:01.96} UT,   3166.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     308252168
X_OFFSET:        685 [pixels]
Y_OFFSET:        980 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       845
Y_GRB_POS:       1140
BINNING_INDEX:   1
IM_URL:          sw00435903000msuni3173.fits
SUN_POSTN:       194.12d {+12h 56m 29s}   -6.04d {-06d 02' 13"}
SUN_DIST:        128.52 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      204.77d {+13h 39m 05s}  -15.24d {-15d 14' 27"}
MOON_DIST:       126.24 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       88.16,-13.66 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      348.52, 45.82 [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 08 Oct 10 17:47:57 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     435903,   Seg_Num: 0
GRB_RA:          328.8741d {+21h 55m 29.78s} (J2000),
                 328.9887d {+21h 55m 57.28s} (current),
                 328.3427d {+21h 53m 22.23s} (1950)
GRB_DEC:         +37.0666d {+37d 03' 59.7"} (J2000),
                 +37.1180d {+37d 07' 04.6"} (current),
                 +36.8289d {+36d 49' 44.2"} (1950)
GRB_ERROR:       4.4 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15477 TJD;   281 DOY;   10/10/08
IMG_START_TIME:  63368.00 SOD {17:36:08.00} UT,   3172.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       194.13d {+12h 56m 30s}   -6.04d {-06d 02' 18"}
SUN_DIST:        128.53 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      204.83d {+13h 39m 19s}  -15.26d {-15d 15' 35"}
MOON_DIST:       126.21 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       88.16,-13.66 [deg] galactic lon,lat of the burst
ECL_COORDS:      348.52, 45.81 [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:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 2.8% < P(seren) < 6.6%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Oct 10 18:32:05 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     435903,   Seg_Num: 0
GRB_RA:          328.8745d {+21h 55m 29.88s} (J2000),
                 328.9891d {+21h 55m 57.37s} (current),
                 328.3430d {+21h 53m 22.33s} (1950)
GRB_DEC:         +37.0660d {+37d 03' 57.6"} (J2000),
                 +37.1174d {+37d 07' 02.4"} (current),
                 +36.8283d {+36d 49' 42.0"} (1950)
GRB_ERROR:       3.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15477 TJD;   281 DOY;   10/10/08
IMG_START_TIME:  63368.00 SOD {17:36:08.00} UT,   3172.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       194.15d {+12h 56m 37s}   -6.05d {-06d 03' 00"}
SUN_DIST:        128.51 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      205.27d {+13h 41m 05s}  -15.41d {-15d 24' 33"}
MOON_DIST:       125.95 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       88.16,-13.66 [deg] galactic lon,lat of the burst
ECL_COORDS:      348.52, 45.81 [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:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 2.8% < P(seren) < 6.6%.

GCN Circular #11319
W. H. Baumgartner (GSFC/UMBC), P. A. Evans (U Leicester), S. T. Holland (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), C. Pagani (U Leicester), K. L. Page (U Leicester), and M. H. Siegel (PSU) report on the behalf of the Swift UVOT team:
The XRT began observing the field of GRB 101008A (Baumgartner et al. 2010, GCNC 11318) at 17:35:56.9 UT, 3161.7 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 328.87463, 37.06580 which is equivalent to:
```
    RA(J2000) =  21h 55m 29.91s
   Dec(J2000) = +37d 03' 56.9"
```
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 48 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. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.44 x 10^21 cm^-2, Kalberla et al. 2005), with an excess column of 3 (+4.38/-2.94) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the white filter starting 3167 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7' x 2.7' sub-image covers 100% of the XRT error circle. The preliminary 3-sigma upper limit in the white filter is 20.3 mag. No correction has been made for the expected Galactic extinction corresponding to a reddening of E_{B-V} = 0.19 mag. Photometry is on the UVOT photometry system of Poole et al. (2008).
GCN Circular #11320
J. Gorosabel (IAA-CSIC, Granada), U. Carsenty (DLR, Berlin), P. Kubanek (IAA-CSIC, Granada & U. of Valencia), G. Hahn (DLR, Berlin), report on behalf of a larger collaboration:
"We have carried out R-band observations of the Swift GRB 101008A (Baumgartner et al., GCNC 11318, GCNC 11319) with the 1.23m Calar Alto telescope. The observations were carried out in R-band on October 8.7957-8.8118 UT (2.38 - 2.76 hours post trigger) under poor atmospheric conditions. We do not detect any optical source consistent with the XRT error circle (Baumgartner et al., GCNC 11319) down to a limiting magnitude of R=19.7 (3 sigma, calibrated against USNO-B1.0)".
GCN Circular #11321
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 1745 s of XRT Photon Counting mode data and 4 UVOT images for GRB 101008A, 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 = 328.87505, +37.06713 which is equivalent to:
```
RA (J2000): 21h 55m 30.01s
Dec (J2000): +37d 04' 01.7"
```
with an uncertainty of 2.0 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 #11324
A. S. Moskvitin, T. A. Fatkhullin, A. V. Zyazeva report on behalf of a larger collaboration:
We have observed the field of the GRB 101008A (Baumgartner et al., GCN#11318, GCN#11319; Beardmore et al., GCN#11321) with the 1m telescope Zeiss-1000 of SAO RAS, Russia. The observations were carried out in Rc band on October, 8.763 -- 8.800 UT (1.581 -- 2.484 hours after the trigger).
We have detected three possible candidates of the OT near the enhanced XRT error box, which are absent in the DSS R-band image. A comparison of the DSS and our images is demonstrated at ftp://ftp.sao.ru/pub/grb/GRB101008A/GRB101008A.jpeg
We have measured the R magnitudes of these three objects according to R2 = 16.33 of the USNO-B1.0 star 1270-0570798:
```
S1 R = 20.84 +/- 0.04
S2 R = 21.03 +/- 0.06
S3 R = 21.01 +/- 0.05
```
All the errors are formal and they do not include the errors of the USNO-B1.0 to Johnson-Cousins photometric system transformation.
This message may be cited.
GCN Circular #11325
C. Pagani (U. Leicester) and W. H. Baumgartner (GSFC/UMBC) report on behalf of the Swift-XRT team:
We have analysed 5.5 ks of XRT data for GRB 101008A (Baumgartner et al. GCN Circ. 11318), from 3169 s to 26.9 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN. Circ 11321).
The light curve can be modelled with a power-law decay with a decay index of alpha=1.2 (+0.5, -0.3).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.0 (+/-0.5). The best-fitting absorption column is 2.8 (+2.0, -1.4) x 10^21 cm^-2, in excess of the Galactic value of 1.4 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 4.5 x 10^-11 (6.8 x 10^-11) erg cm^-2 count^-1.
If the light curve continues to decay with a power-law decay index of 1.2, the count rate at T+24 hours will be 1.3 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.9 x 10^-14 (8.9 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00435903.
This circular is an official product of the Swift-XRT team.
GCN Circular #11326
M. Nardini, P. Schady, J. Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 101008A (Swift trigger 435903; Baumgartner et al., GCN#11318) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile).
Observations started at 00:26 UT 2010 October 9th, 7.8h time after the GRB trigger, and lasted 2 hours. They were performed at an average seeing of 1.2 and at an average airmass of 2.5.
In all our g'r'i'z'JHK images we detect the 3 objects reported by Moskvitin et al., GCN#11324.
While sources S1 and S3 do not show any clear fading with respect to that reported by Moskvitin et al., GCN#11324, our preliminary photometry shows that S2 has faded with respect to the value reported by Moskvitin et al. (GCN#11324). Calibrating our images against the same USNO star as Moskvitin et al., we calculate a fading of ~0.7mag between the GROND preliminary photometry centred at 8.7h after the trigger and that reported in Moskvitin et al.
We therefore conclude that this is the optical/NIR afterglow of GRB101008A.
Our photometry is not corrected for foreground extinction of E(B-V)=0.19. The detection in g' band implies a redshift constraint z<3.5.
GCN Circular #11327
S. D. Barthelmy (GSFC), T. Sakamoto (GSFC/UMBC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-248 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 101008A (trigger #435903) (Baumgartner, et al., GCN Circ. 11318). The BAT ground-calculated position is RA, Dec = 328.882, 37.060 deg which is
```
   RA(J2000)  =  21h 55m 31.8s 
   Dec(J2000) = +37d 03' 36.4" 
```
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 58%.
The mask-weighted light curve shows a single FRED-like peak starting ~T-30 sec, peaking at ~T+0 sec, and returning to background at ~T+100 sec. T90 (15-350 keV) is 104 +- 35 sec (estimated error including systematics).
The time-averaged spectrum from T-4.0 to T+106.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.59 +- 0.24. The fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.42 sec in the 15-150 keV band is 1.6 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/435903/BA/
GCN Circular #11328
V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov Ural State University, Kourovka
K.Ivanov, O.Chuvalaev, V.Poleschuk, E.Konstantinov, V.Lenok, O.Gres, S.Yazev, N.M.Budnev, Irkutsk State University
E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M. Kornilov Sternberg Astronomical Institute, Moscow State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk
MASTER-Net robotic telescopes (MASTER-Net: http://observ.pereplet.ru) located near Ekaterinburg (Kourovka) and Tunka (Baykal Lake) was pointed to the Swift GRB 101008A (Baumgartner et al., GCN#11318, GCN#11319; Beardmore et al., GCN#11321) 53 s after trigger time (immediately after roof opening and with last night focus) and 8309s after trigger time (the Tunka delay was due to weather conditions).
Time duration of the GRB 101008A is 104 +- 35 sec (Barthelmy et al., GCN#11327). So we have prompt optical limit at Kourovka site. We see marginaly possible OT (S2, Moskvitin et al.,GCN#11324; Nardini et al., GCN#11326) at Tunka observations.
We have next unfiltered estimation:
```
t_start-t_trig(s)   mean time     exp_time(s)     m             Coadd? 
Site
--------------------------------------------------------------------------
       53            58    10         >14.5        N             Kourovka
       53           141   410         >16.0        Y             Kourovka
     8309         10260   540       19.5+-1.0      Y             Tunka
--------------------------------------------------------------------------
```
MASTER II have 2 images per exposition time. The message may be cited.
mailto: lipunov@sai.msu.ru

GCN Circular #11329
I am sorry, the table in GCN#11328 is :

t_start-t_trig(s)   mean time     exp_time(s)     m      Coadd?    Site
--------------------------------------------------------------------------
       53              58            10          >14.5     N      Kourovka
       53             141           410          >16.0     Y      Kourovka
     8309           10260           540        19.5+-1.0   Y      Tunka
--------------------------------------------------------------------------

The message may be cited.
mailto: lipunov@sai.msu.ru

GCN Circular #11330
Lin Lin (UAH) report on behalf of the Fermi GBM Team:
"At 16:43:15.61 UT on 08 Oct. 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 101008A (trigger 308248997 / 101008697).
The burst was also detected by the SWIFT-BAT (W. H. Baumgartner et al. 2010, GCN 11318) The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 79 degrees.
The GBM light curve shows a fast rise - slow decay peak with a duration (T90) of about 7 s (50-300 keV). The time-averaged spectrum from T0-1.536 s to T0+5.376 s is best fit by a simple power law function with index -1.42 +/- 0.03 (C-stat 1249.1 for 612 d.o.f.).
The event fluence (10-1000 keV) over the above time interval is (2.016 +/- 0.083)E-6 erg/cm^2. The 0.064-sec peak photon flux measured starting from T0+1.344 s in the 10-1000 keV band is 4.90 +/- 0.84 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #11352
V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 101008A (Baumgartner et al., GCN 11318) with ZTE telescope of SAI MSU observatory on Oct. 12 (UT) 18:57 - 20:42. We clearly detect objects S1 and S3 (Moskvitin et al., GCN 11324) in coordinates (J2000) RA=21 55 29.91, Dec=+37 03 56.6 and RA=21 55 29.85, Dec=+37 04 05.0, correspondingly. We do not detect the object S2 (Moskvitin et al., GCN 11324; Nardini et al., GCN 11326). The photometry is based on the same USNO star as Moskvitin et al.
```
Source,  T0+,     Filter,   Exposure,    mag.,        Upper Limit (3 sigma)
             (mid, d)              (s)

S1        4.1297    R       97x60           21.0 +/- 0.1      22.4
S2        4.1297    R       97x60           21.6 +/- 0.2      22.4
```
Since we do not detect the afterglow candidate S2 up to R=22.4 we can confirm the GRB 101008A afterglow detection. The finding chart can be found at http://grb.rssi.ru/GRB101008A/GRB101008a_101012_ZTE.gif
GCN Circular #11353
V. Rumyantsev (CrAO), =A0A. Pozanenko (IKI) =A0report on behalf of larger GRB follow-up collaboration:
We do not detect the object =A0S2 =A0(Moskvitin =A0et al., GCN 11324; Nardini et al., GCN 11326). And the table should be read as
Source, =A0T0+, =A0 =A0 Filter, =A0 Exposure, =A0 =A0mag., =A0 =A0 =A0 =A0= Upper Limit (3 sigma) =A0 =A0 =A0 =A0 =A0 =A0 =A0(mid, d) =A0 =A0 =A0 =A0 =A0 =A0 =A0(s)
S1 =A0 =A0 =A0 =A04.1297 =A0 =A0R =A0 =A0 =A0 97x60 =A0 =A0 =A0 =A0 =A0 2= 1.0 +/- 0.1 =A0 =A0 =A022.4 S3 =A0 =A0 =A0 =A04.1297 =A0 =A0R =A0 =A0 =A0 97x60 =A0 =A0 =A0 =A0 =A0 2= 1.6 +/- 0.2
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Jochen Greiner, last update: 08-Oct-2010 [Disclaimer]