Gamma-ray Burst 081016B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 16 Oct 08 19:47:54 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     331856,   Seg_Num: 0
GRB_RA:           14.615d {+00h 58m 28s} (J2000),
                  14.716d {+00h 58m 52s} (current),
                  14.040d {+00h 56m 10s} (1950)
GRB_DEC:         -43.543d {-43d 32' 34"} (J2000),
                 -43.496d {-43d 29' 43"} (current),
                 -43.813d {-43d 48' 45"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       8138 [cnts]    Image_Peak=246 [image_cnts]
TRIGGER_DUR:     2.048 [sec] 
TRIGGER_INDEX:   486     E_range: 50-350 keV
BKG_INTEN:       76121 [cnts]
BKG_TIME:        71196.81 SOD {19:46:36.81} UT
BKG_DUR:         24 [sec]
GRB_DATE:        14755 TJD;   290 DOY;   08/10/16
GRB_TIME:        71234.51 SOD {19:47:14.51} UT
GRB_PHI:          13.02 [deg]
GRB_THETA:        17.26 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     19.69 [sigma]
IMAGE_SIGNIF:    7.48 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +3  +6  +0  +0 +59  +0 
SUN_POSTN:       202.05d {+13h 28m 12s}   -9.24d {-09d 14' 33"}
SUN_DIST:        126.84 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.89d {+03h 07m 34s}  +22.77d {+22d 45' 59"}
MOON_DIST:        72.55 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.44,-73.52 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      351.39,-44.81 [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 = 112.97,1.21 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 16 Oct 08 19:48:54 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     331856,   Seg_Num: 0
POINT_RA:         14.617d {+00h 58m 28s} (J2000)
POINT_DEC:       -43.538d {-43d 32' 18"} (J2000)
IMG_START_DATE:  14755 TJD;   290 DOY;   08/10/16
IMG_START_TIME:  71325.14 SOD {19:48:45.14} UT,   90.6 [sec] since BAT Trigger Time
COUNTS:          5    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/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 16 Oct 08 19:50:49 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     331856,   Seg_Num: 0
GRB_RA:           14.615d {+00h 58m 28s} (J2000),
                  14.716d {+00h 58m 52s} (current),
                  14.040d {+00h 56m 10s} (1950)
GRB_DEC:         -43.543d {-43d 32' 34"} (J2000),
                 -43.496d {-43d 29' 43"} (current),
                 -43.813d {-43d 48' 45"} (1950)
GRB_DATE:        14755 TJD;   290 DOY;   08/10/16
GRB_TIME:        71234.51 SOD {19:47:14.51} UT
TRIGGER_INDEX:   486
GRB_PHI:          13.02 [deg]
GRB_THETA:        17.26 [deg]
DELTA_TIME:      71.00 [sec]
TRIGGER_DUR:     2.048 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     19.69 [sigma]
IMAGE_SIGNIF:    7.48 [sigma]
LC_URL:          sw00331856000msb.lc
SUN_POSTN:       202.05d {+13h 28m 12s}   -9.24d {-09d 14' 36"}
SUN_DIST:        126.84 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.92d {+03h 07m 41s}  +22.77d {+22d 46' 28"}
MOON_DIST:        72.57 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.44,-73.52 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      351.39,-44.81 [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 = 112.97,1.21 [deg].

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 16 Oct 08 19:51:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     331856,   Seg_Num: 0
POINT_RA:         14.617d {+00h 58m 28s} (J2000)
POINT_DEC:       -43.538d {-43d 32' 17"} (J2000)
POINT_ROLL:      189.196d
IMG_START_DATE:  14755 TJD;   290 DOY;   08/10/16
IMG_START_TIME:  71327.55 SOD {19:48:47.55} UT,   93.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.674
N_STARS:         69
X_OFFSET:        515 [pixels]
Y_OFFSET:        558 [pixels]
X_MAX:           1474 [pixels]
Y_MAX:           1517 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00331856000msufc0093.fits
SUN_POSTN:       202.05d {+13h 28m 12s}   -9.24d {-09d 14' 36"}
SUN_DIST:        126.84 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.93d {+03h 07m 44s}  +22.78d {+22d 46' 38"}
MOON_DIST:        72.57 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.43,-73.53 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      351.39,-44.81 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 16 Oct 08 19:52:25 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     331856,   Seg_Num: 0
POINT_RA:         14.617d {+00h 58m 28s} (J2000)
POINT_DEC:       -43.538d {-43d 32' 17"} (J2000)
POINT_ROLL:      189.196d
IMG_START_DATE:  14755 TJD;   290 DOY;   08/10/16
IMG_START_TIME:  71327.55 SOD {19:48:47.55} UT,   93.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.674
N_STARS:         69
X_OFFSET:        515 [pixels]
Y_OFFSET:        558 [pixels]
X_MAX:           1474 [pixels]
Y_MAX:           1517 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00331856000msufc0093.fits
SUN_POSTN:       202.05d {+13h 28m 12s}   -9.24d {-09d 14' 37"}
SUN_DIST:        126.84 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.94d {+03h 07m 45s}  +22.78d {+22d 46' 44"}
MOON_DIST:        72.58 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.43,-73.53 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      351.39,-44.81 [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:     Thu 16 Oct 08 19:53:11 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     331856,   Seg_Num: 0
POINT_RA:         14.617d {+00h 58m 28s} (J2000)
POINT_DEC:       -43.538d {-43d 32' 17"} (J2000)
ROLL:            189.196d
IMG_START_DATE:  14755 TJD;   290 DOY;   08/10/16
IMG_START_TIME:  71327.55 SOD {19:48:47.55} UT,   93.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     245879330
X_OFFSET:        834 [pixels]
Y_OFFSET:        877 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       994
Y_GRB_POS:       1037
BINNING_INDEX:   1
IM_URL:          sw00331856000msuni0093.fits
SUN_POSTN:       202.05d {+13h 28m 12s}   -9.24d {-09d 14' 38"}
SUN_DIST:        126.84 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.95d {+03h 07m 47s}  +22.78d {+22d 46' 51"}
MOON_DIST:        72.58 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.43,-73.53 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      351.39,-44.81 [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:     Thu 16 Oct 08 19:53:31 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     331856,   Seg_Num: 0
POINT_RA:         14.617d {+00h 58m 28s} (J2000)
POINT_DEC:       -43.538d {-43d 32' 17"} (J2000)
ROLL:            189.196d
IMG_START_DATE:  14755 TJD;   290 DOY;   08/10/16
IMG_START_TIME:  71327.55 SOD {19:48:47.55} UT,   93.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     245879330
X_OFFSET:        834 [pixels]
Y_OFFSET:        877 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       994
Y_GRB_POS:       1037
BINNING_INDEX:   1
IM_URL:          sw00331856000msuni0093.fits
SUN_POSTN:       202.05d {+13h 28m 12s}   -9.24d {-09d 14' 38"}
SUN_DIST:        126.84 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.95d {+03h 07m 48s}  +22.78d {+22d 46' 55"}
MOON_DIST:        72.58 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.43,-73.53 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      351.39,-44.81 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 16 Oct 08 19:53:54 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     331856,   Seg_Num: 0
POINT_RA:         14.620d {+00h 58m 29s} (J2000)
POINT_DEC:       -43.539d {-43d 32' 20"} (J2000)
POINT_ROLL:      189.193d
IMG_START_DATE:  14755 TJD;   290 DOY;   08/10/16
IMG_START_TIME:  71486.05 SOD {19:51:26.05} UT,   251.5 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.068
N_STARS:         31
X_OFFSET:        275 [pixels]
Y_OFFSET:        318 [pixels]
X_MAX:           1714 [pixels]
Y_MAX:           1757 [pixels]
DET_THRESH:      3
PHOTO_THRESH:    2
SL_URL:          sw00331856000msufc0251.fits
SUN_POSTN:       202.05d {+13h 28m 12s}   -9.24d {-09d 14' 38"}
SUN_DIST:        126.84 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.96d {+03h 07m 49s}  +22.78d {+22d 46' 58"}
MOON_DIST:        72.59 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.43,-73.53 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      351.40,-44.81 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 16 Oct 08 19:54:30 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     331856,   Seg_Num: 0
POINT_RA:         14.620d {+00h 58m 29s} (J2000)
POINT_DEC:       -43.539d {-43d 32' 20"} (J2000)
POINT_ROLL:      189.193d
IMG_START_DATE:  14755 TJD;   290 DOY;   08/10/16
IMG_START_TIME:  71486.05 SOD {19:51:26.05} UT,   251.5 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.068
N_STARS:         31
X_OFFSET:        275 [pixels]
Y_OFFSET:        318 [pixels]
X_MAX:           1714 [pixels]
Y_MAX:           1757 [pixels]
DET_THRESH:      3
PHOTO_THRESH:    2
SL_URL:          sw00331856000msufc0251.fits
SUN_POSTN:       202.05d {+13h 28m 13s}   -9.24d {-09d 14' 39"}
SUN_DIST:        126.84 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.96d {+03h 07m 51s}  +22.78d {+22d 47' 04"}
MOON_DIST:        72.59 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.43,-73.53 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      351.40,-44.81 [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:     Thu 16 Oct 08 19:55:25 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     331856,   Seg_Num: 0
POINT_RA:         14.620d {+00h 58m 29s} (J2000)
POINT_DEC:       -43.539d {-43d 32' 20"} (J2000)
ROLL:            189.193d
IMG_START_DATE:  14755 TJD;   290 DOY;   08/10/16
IMG_START_TIME:  71486.05 SOD {19:51:26.05} UT,   251.5 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     245879489
X_OFFSET:        834 [pixels]
Y_OFFSET:        877 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       994
Y_GRB_POS:       1037
BINNING_INDEX:   1
IM_URL:          sw00331856000msuni0251.fits
SUN_POSTN:       202.05d {+13h 28m 13s}   -9.24d {-09d 14' 40"}
SUN_DIST:        126.84 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.97d {+03h 07m 53s}  +22.79d {+22d 47' 13"}
MOON_DIST:        72.60 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.43,-73.53 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      351.40,-44.81 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 16 Oct 08 19:54:58 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     331856,   Seg_Num: 0
POINT_RA:         14.620d {+00h 58m 29s} (J2000)
POINT_DEC:       -43.539d {-43d 32' 20"} (J2000)
ROLL:            189.193d
IMG_START_DATE:  14755 TJD;   290 DOY;   08/10/16
IMG_START_TIME:  71486.05 SOD {19:51:26.05} UT,   251.5 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     245879489
X_OFFSET:        834 [pixels]
Y_OFFSET:        877 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       994
Y_GRB_POS:       1037
BINNING_INDEX:   1
IM_URL:          sw00331856000msuni0251.fits
SUN_POSTN:       202.05d {+13h 28m 13s}   -9.24d {-09d 14' 39"}
SUN_DIST:        126.84 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.97d {+03h 07m 52s}  +22.79d {+22d 47' 09"}
MOON_DIST:        72.59 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.43,-73.53 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      351.40,-44.81 [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:     Thu 16 Oct 08 19:54:36 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     331856,   Seg_Num: 0
GRB_RA:           14.5670d {+00h 58m 16.08s} (J2000),
                  14.6679d {+00h 58m 40.30s} (current),
                  13.9920d {+00h 55m 58.08s} (1950)
GRB_DEC:         -43.5296d {-43d 31' 46.5"} (J2000),
                 -43.4822d {-43d 28' 56.0"} (current),
                 -43.7994d {-43d 47' 57.8"} (1950)
GRB_ERROR:       3.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  14755 TJD;   290 DOY;   08/10/16
IMG_START_TIME:  71350.00 SOD {19:49:10.00} UT,   115.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       202.05d {+13h 28m 13s}   -9.24d {-09d 14' 39"}
SUN_DIST:        126.85 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
MOON_POSTN:       46.96d {+03h 07m 51s}  +22.78d {+22d 47' 05"}
MOON_DIST:        72.60 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      298.56,-73.54 [deg] galactic lon,lat of the burst
ECL_COORDS:      351.36,-44.78 [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 Circular #8381
K. L. Page (U Leicester), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), P. A. Evans (U Leicester), O. Godet (U Leicester), C. Guidorzi (INAF-OAB), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), W.B Landsman (GSFC), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester), D. M. Palmer (LANL), M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester), M. C. Stroh (PSU), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the Swift Team:
At 19:47:14 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 081016B (trigger=331856). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 14.615, -43.543 which is
```
   RA(J2000)  =  00h 58m 28s
   Dec(J2000) = -43d 32' 34"
```
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 5 sec. The peak count rate was ~1600 counts/sec (15-350 keV), at ~2 sec after the trigger.
The XRT began observing the field at 19:48:45.1 UT, 90.6 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued, fading X-ray source located at RA, Dec 14.5670, -43.5296 which is equivalent to:
```
   RA(J2000)  = 00h 58m 16.08s
   Dec(J2000) = -43d 31' 46.6"
```
with an uncertainty of 3.3 arcseconds (radius, 90% containment). This location is 134 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 1.96e+20 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 150 seconds with the White (160-650 nm) filter starting 93 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01.
Burst Advocate for this burst is K. L. Page (kpa AT star.le.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 Circular #8383
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 2096 s of XRT Photon Counting mode data and 1 UVOT images for GRB 081016B, 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 = 14.56434, -43.53015 which is equivalent to:
```
RA (J2000): 00h 58m 15.44s
Dec (J2000): -43d 31' 48.5"
```
with an uncertainty of 2.1 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 http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an extension of this method.
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #8384
K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:
We have analysed the first six orbits of the XRT data obtained for GRB 081016B (Page et al., GCN Circ. 8381). After an initial 18 seconds in Windowed Timing mode, the remaining 3.5 ks were collected in Photon Counting (PC) mode. The UVOT-enhanced position was given by Osborne et al. in GCN Circ. 8383.
The first orbit of data shows a decay of alpha = 1.1 +/- 0.3. However, after the end of this orbit (~265 s after the trigger), the source is no longer detected, indicating a break to a significantly steeper decay occurred.
The spectrum of the first orbit of PC data can be modelled with a power-law (Gamma = 1.20 +/- 0.18) absorbed at the Galactic value of NH = 1.96x10^20 cm^-2. The upper limit on the total absorbing column is 2.2x10^21 cm^-2. The observed (unabsorbed) flux over this time is 2.43x10^-10 (2.48x10^-10) erg cm^-2 s^-1, corresponding to a counts to observed flux conversion of 6.8x10^-11 erg cm^-2 count^-1.
Because of the lack of detection after the first orbit, we cannot predict the future count rate.
This is an official product of the Swift-XRT team.
GCN Circular #8386
W.Landsman (GSFC) and K. L. Page (U Leicester), on behalf of the Swift/UVOT team.
The Swift Ultra-Violet/Optical Telescope (UVOT) began settled observations of GRB 081016B (trigger 331856) 93 seconds after the BAT trigger (Page et al.,GCN Circ. 8381). No afterglow is detected at the enhanced XRT position (Osborne et al., GCN Circ. 8383) in the initial white finding chart or subsequent images. The limiting magnitudes (3-sigma in 3" radius apertures) in each of the UVOT filters are as follows:
```
Filter  T_start(s)  T_stop(s)  Exp(s)  Mag UL (3sig)

white       93       243       150     >21.5
b         4710      4823       113     >20.6
v         5373      5572       197     >20.0
u         5988     11724       960     >21.5
uvw1      5783      5982       197     >20.3
uvm2      5577      5777       197     >20.0
uvw2      5168      5368       197     >20.3
```
The values quoted above are in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627). They are not corrected for the expected Galactic extinction corresponding to a reddening of E(B-V)=0.01 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #8387
M. Stamatikos (GSFC/ORAU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), K. L. Page (U Leicester),D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 081016B (trigger #331856) (Page, et al., GCN Circ. 8381). The BAT ground-calculated position is RA, Dec = 14.582, -43.536 deg which is
```
  RA(J2000)  =  00h 58m 19.8s
  Dec(J2000) = -43d 32' 07.9"
```
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 98%.
The BAT mask-weighted light curve showed a single peak of duration ~2.5 seconds. T90 (15-350 keV) is 2.6 +- 0.8 sec (estimated error including systematics).
The time-averaged spectrum from T-0.0 to T+3.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.92 +- 0.32. The fluence in the 15-150 keV band is 9.9 +- 1.8 x 10-08 erg/cm2. The 1-sec peak photon flux measured from T+0.50 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/331856/BA/
GCN Report 170.1
GCN_Report 170.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_170_1.pdf by K.L. Page at U. Leicester titled: "Final Swift report on GRB 081016B"
GCN Circular #8534
B. E. Cobb (UC Berkeley) reports:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 081016b (Page et al. GCN 8381) with a mid-exposure time of 4.3 hours post-burst (2008-10-17 00:06 UT). Total summed exposure times amounted to 36 minutes in I and 30 minutes in J.
No source is detected at the position of the X-ray afterglow (Osborne et al. GCN 8383) to approximate limiting magnitudes of I > 22.1 and J > 19.8. Magnitudes are calibrated using Landolt standard stars in I, and 2MASS stars in J.

Back to JG's homepage

Jochen Greiner, last update: 20-Nov-2008 [Disclaimer]