Gamma-ray Burst 051016B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:28:25 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     159994,   Seg_Num: 0
  GRB_RA:          132.067d {+08h 48m 16s} (J2000),
                   132.147d {+08h 48m 35s} (current),
                   131.375d {+08h 45m 30s} (1950)
  GRB_DEC:         +13.658d {+13d 39' 27"} (J2000),
                   +13.636d {+13d 38' 09"} (current),
                   +13.843d {+13d 50' 34"} (1950)
  GRB_ERROR:       4.00 [arcmin radius, statistical only]
  GRB_INTEN:       2745 [cnts]    Image_Peak=137 [image_cnts]
  TRIGGER_DUR:     0.512 [sec] 
  TRIGGER_INDEX:   121     E_range: 25-100 keV
  BKG_INTEN:       31921 [cnts]
  BKG_TIME:        66472.00 SOD {18:27:52.00} UT
  BKG_DUR:         8 [sec]
  GRB_DATE:        13659 TJD;   289 DOY;   05/10/16
  GRB_TIME:        66488.98 SOD {18:28:08.98} UT
  GRB_PHI:         -168.36 [deg]
  GRB_THETA:        33.28 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     15.03 [sigma]
  IMAGE_SIGNIF:    7.15 [sigma]
  MERIT_PARAMS:     +1  +0  +0  +0  +2  +5  +0  +0 -29  +1 
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 20"}
  SUN_DIST:         72.71 [deg]
  MOON_POSTN:       12.52d {+00h 50m 04s}   +5.46d {+05d 27' 24"}
  MOON_DIST:       117.12 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.34, 31.98 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      130.74, -4.03 [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.  
  

• red DSS finding chart ps-file
  
  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:30:06 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     159994,   Seg_Num: 0 
  GRB_RA:          132.1150d {+08h 48m 27.6s} (J2000),
                   132.1950d {+08h 48m 46.8s} (current),
                   131.4237d {+08h 45m 41.6s} (1950)
  GRB_DEC:         +13.6571d {+13d 39' 25.5"} (J2000),
                   +13.6355d {+13d 38' 07.6"} (current),
                   +13.8426d {+13d 50' 33.2"} (1950)
  GRB_ERROR:       5.8 [arcsec radius, statistical plus systematic, 90%
  +containment]
  GRB_INTEN:       262.03 [arb]
  GRB_SIGNIF:      5.91 [sigma]
  GRB_DATE:        13659 TJD;   289 DOY;   05/10/16
  GRB_TIME:        66563.87 SOD {18:29:23.87} UT     [Start of CCD integration]
  TAM[0-3]:        327.61 237.19 261.27 242.87
  AMPLIFIER:       2 
  WAVEFORM:        134
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 22"}
  SUN_DIST:         72.67 [deg]
  MOON_POSTN:       12.53d {+00h 50m 07s}   +5.46d {+05d 27' 46"}
  MOON_DIST:       117.15 [deg]  
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.36, 32.03 [deg] galactic lon,lat of the burst 
  ECL_COORDS:      130.79, -4.02 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Coordinates.
  COMMENTS:        WARNING: XRT alignment calibration is on-going, and there may be
  COMMENTS:        residual systematic offsets of several arcseconds not accounted for yet 
  COMMENTS:        by our on-board position determination algorithm.  We have increased
  COMMENTS:        the estimated error circle radius to take this into account.
  

• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:30:07 UT
  NOTICE_TYPE:     Swift-XRT Image
  TRIGGER_NUM:     159994,   Seg_Num: 0
  GRB_RA:          132.1150d {+08h 48m 27.6s} (J2000),
                   132.1950d {+08h 48m 46.8s} (current),
                   131.4237d {+08h 45m 41.6s} (1950)
  GRB_DEC:         +13.6571d {+13d 39' 25.5"} (J2000),
                   +13.6355d {+13d 38' 07.6"} (current),
                   +13.8426d {+13d 50' 33.2"} (1950)
  GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
  GRB_INTEN:       35 [cnts]
  IMG_START_DATE:  13659 TJD;   289 DOY;   05/10/16
  IMG_START_TIME:  66563.87 SOD {18:29:23.87} UT
  CENTROID_X:      248.37,  raw= 248  [pixels]
  CENTROID_Y:      308.40,  raw= 308  [pixels]
  ROLL:            104.23 [deg]
  GAIN:            1
  MODE:            3, Long Image mode
  WAVEFORM:        134
  EXPO_TIME:       2.50 [sec]
  GRB_POS_XRT_Y:   19.66
  GRB_POS_XRT_Z:   -119.50
  IMAGE_URL:       sw00159994000msxim.img
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 22"}
  SUN_DIST:         72.67 [deg]
  MOON_POSTN:       12.53d {+00h 50m 07s}   +5.46d {+05d 27' 46"}
  MOON_DIST:       117.15 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.36, 32.03 [deg] galactic lon,lat of the burst
  ECL_COORDS:      130.79, -4.02 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Image.  
  COMMENTS:        WARNING: XRT alignment calibration is on-going, and there may be  
  COMMENTS:        residual systematic offsets of several arcseconds not accounted for yet  
  COMMENTS:        by our on-board position determination algorithm.  We have increased  
  COMMENTS:        the estimated error circle radius to take this into account.  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:30:06 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     159994,   Seg_Num: 0
  GRB_RA:          132.1150d {+08h 48m 27.6s} (J2000),
                   132.1950d {+08h 48m 46.8s} (current),
                   131.4237d {+08h 45m 41.6s} (1950)
  GRB_DEC:         +13.6571d {+13d 39' 25.5"} (J2000),
                   +13.6355d {+13d 38' 07.6"} (current),
                   +13.8426d {+13d 50' 33.2"} (1950)
  GRB_ERROR:       5.8 [arcsec radius, statistical plus systematic, 90% containment]
  GRB_INTEN:       262.03 [arb]
  GRB_SIGNIF:      5.91 [sigma]
  GRB_DATE:        13659 TJD;   289 DOY;   05/10/16
  GRB_TIME:        66563.87 SOD {18:29:23.87} UT     [Start of CCD integration]
  TAM[0-3]:        327.61 237.19 261.27 242.87
  AMPLIFIER:       2
  WAVEFORM:        134
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 22"}
  SUN_DIST:         72.67 [deg]
  MOON_POSTN:       12.53d {+00h 50m 07s}   +5.46d {+05d 27' 46"}
  MOON_DIST:       117.15 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.36, 32.03 [deg] galactic lon,lat of the burst
  ECL_COORDS:      130.79, -4.02 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Coordinates.  
  COMMENTS:        WARNING: XRT alignment calibration is on-going, and there may be  
  COMMENTS:        residual systematic offsets of several arcseconds not accounted for yet  
  COMMENTS:        by our on-board position determination algorithm.  We have increased  
  COMMENTS:        the estimated error circle radius to take this into account.  
  

• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:30:39 UT
  NOTICE_TYPE:     Swift-XRT Processed Image
  TRIGGER_NUM:     159994,   Seg_Num: 0
  GRB_RA:          132.1150d {+08h 48m 27.6s} (J2000),
                   132.1950d {+08h 48m 46.8s} (current),
                   131.4237d {+08h 45m 41.6s} (1950)
  GRB_DEC:         +13.6571d {+13d 39' 25.5"} (J2000),
                   +13.6355d {+13d 38' 07.6"} (current),
                   +13.8426d {+13d 50' 33.2"} (1950)
  GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
  GRB_INTEN:       35 [cnts]
  IMG_START_DATE:  13659 TJD;   289 DOY;   05/10/16
  IMG_START_TIME:  66563.87 SOD {18:29:23.87} UT
  CENTROID_X:      248.37,  raw= 248  [pixels]
  CENTROID_Y:      308.40,  raw= 308  [pixels]
  ROLL:            104.23 [deg]
  GAIN:            1
  MODE:            3, Long Image mode
  WAVEFORM:        134
  EXPO_TIME:       2.50 [sec]
  GRB_POS_XRT_Y:   19.66
  GRB_POS_XRT_Z:   -119.50
  IMAGE_URL:       sw00159994000msxim.img
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 22"}
  SUN_DIST:         72.67 [deg]
  MOON_POSTN:       12.53d {+00h 50m 07s}   +5.46d {+05d 27' 46"}
  MOON_DIST:       117.15 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.36, 32.03 [deg] galactic lon,lat of the burst
  ECL_COORDS:      130.79, -4.02 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Processed Image.  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:33:30 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     159994,   Seg_Num: 0
  GRB_RA:          132.067d {+08h 48m 16s} (J2000),
                   132.147d {+08h 48m 35s} (current),
                   131.375d {+08h 45m 30s} (1950)
  GRB_DEC:         +13.658d {+13d 39' 27"} (J2000),
                   +13.636d {+13d 38' 09"} (current),
                   +13.843d {+13d 50' 34"} (1950)
  GRB_DATE:        13659 TJD;   289 DOY;   05/10/16
  GRB_TIME:        66488.98 SOD {18:28:08.98} UT
  TRIGGER_INDEX:   121
  GRB_PHI:         -168.36 [deg]
  GRB_THETA:        33.28 [deg]
  DELTA_TIME:      65460.00 [sec]
  TRIGGER_DUR:     0.512 [sec] 
  LC_URL:          sw00159994000msb.lc
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 20"}
  SUN_DIST:         72.71 [deg]
  MOON_POSTN:       12.52d {+00h 50m 04s}   +5.46d {+05d 27' 24"}
  MOON_DIST:       117.12 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.34, 31.98 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      130.74, -4.03 [deg] ecliptic lon,lat of the pointing direction
  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.  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:34:12 UT
  NOTICE_TYPE:     Swift-XRT Lightcurve
  TRIGGER_NUM:     159994,   Seg_Num: 0
  POINT_RA:        132.079d {+08h 48m 19s} (J2000)
  POINT_DEC:       +13.657d {+13d 39' 25"} (J2000)
  LC_START_DATE:   13659 TJD;   289 DOY;   05/10/16
  LC_START_TIME:   66569.20 SOD {18:29:29.20} UT
  LC_STOP_DATE:    13659 TJD;   289 DOY;   05/10/16
  LC_STOP_TIME:    66786.72 SOD {18:33:06.72} UT
  LC_LIVE_TIME:    213.90 [sec], 98.3%
  DELTA_TIME:      86182.48 [sec]
  N_BINS:          100
  TERM_COND:       0
  LC_URL:          sw00159994000msx.lc
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 22"}
  SUN_DIST:         72.70 [deg]
  MOON_POSTN:       12.53d {+00h 50m 07s}   +5.46d {+05d 27' 47"}
  MOON_DIST:       117.12 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.35, 31.99 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      130.75, -4.03 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-XRT Lightcurve.  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:37:48 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     159994,   Seg_Num: 0
  POINT_RA:        132.080d {+08h 48m 19s} (J2000)
  POINT_DEC:       +13.659d {+13d 39' 33"} (J2000)
  POINT_ROLL:      104.226d
  GRB_DATE:        13659 TJD;   289 DOY;   05/10/16
  GRB_TIME:        66567.18 SOD {18:29:27.18} UT
  FILTER:          3, V
  BKG_MEAN:        2.061
  N_STARS:         29
  X_OFFSET:        726 [pixels]
  Y_OFFSET:        326 [pixels]
  X_MAX:           1685 [pixels]
  Y_MAX:           1285 [pixels]
  DET_THRESH:      12
  PHOTO_THRESH:    6
  SL_URL:          sw00159994000msufc.fits
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 22"}
  SUN_DIST:         72.70 [deg]
  MOON_POSTN:       12.53d {+00h 50m 07s}   +5.46d {+05d 27' 46"}
  MOON_DIST:       117.12 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.35, 32.00 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      130.76, -4.03 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:38:43 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     159994,   Seg_Num: 0
  POINT_RA:        132.080d {+08h 48m 19s} (J2000)
  POINT_DEC:       +13.659d {+13d 39' 33"} (J2000)
  POINT_ROLL:      104.226d
  GRB_DATE:        13659 TJD;   289 DOY;   05/10/16
  GRB_TIME:        66567.18 SOD {18:29:27.18} UT
  FILTER:          3, V
  BKG_MEAN:        2.061
  N_STARS:         29
  X_OFFSET:        726 [pixels]
  Y_OFFSET:        326 [pixels]
  X_MAX:           1685 [pixels]
  Y_MAX:           1285 [pixels]
  DET_THRESH:      12
  PHOTO_THRESH:    6
  SL_URL:          sw00159994000msufc.fits
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 22"}
  SUN_DIST:         72.70 [deg]
  MOON_POSTN:       12.53d {+00h 50m 07s}   +5.46d {+05d 27' 46"}
  MOON_DIST:       117.12 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.35, 32.00 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      130.76, -4.03 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  COMMENTS:        All 4 attachments are included.  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:39:09 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     159994,   Seg_Num: 0
  POINT_RA:        132.080d {+08h 48m 19s} (J2000)
  POINT_DEC:       +13.659d {+13d 39' 33"} (J2000)
  ROLL:            104.226d
  GRB_DATE:        13659 TJD;   289 DOY;   05/10/16
  GRB_TIME:        66567.18 SOD {18:29:27.18} UT
  FILTER:          3, V
  EXPOSURE_ID:     151180166
  X_OFFSET:        1046 [pixels]
  Y_OFFSET:        646 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1206
  Y_GRB_POS:       806
  BINNING_INDEX:   1
  IM_URL:          sw00159994000msuni.fits
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 22"}
  SUN_DIST:         72.70 [deg]
  MOON_POSTN:       12.53d {+00h 50m 07s}   +5.46d {+05d 27' 46"}
  MOON_DIST:       117.12 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.35, 32.00 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      130.76, -4.03 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Image.  
  COMMENTS:        The GRB Position came from the XRT Position Command.  
  COMMENTS:        The image has 2x2 binning (compression).  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 16 Oct 05 18:39:28 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     159994,   Seg_Num: 0
  POINT_RA:        132.080d {+08h 48m 19s} (J2000)
  POINT_DEC:       +13.659d {+13d 39' 33"} (J2000)
  ROLL:            104.226d
  GRB_DATE:        13659 TJD;   289 DOY;   05/10/16
  GRB_TIME:        66567.18 SOD {18:29:27.18} UT
  FILTER:          3, V
  EXPOSURE_ID:     151180166
  X_OFFSET:        1046 [pixels]
  Y_OFFSET:        646 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1206
  Y_GRB_POS:       806
  BINNING_INDEX:   1
  IM_URL:          sw00159994000msuni.fits
  SUN_POSTN:       201.74d {+13h 26m 58s}   -9.12d {-09d 07' 22"}
  SUN_DIST:         72.70 [deg]
  MOON_POSTN:       12.53d {+00h 50m 07s}   +5.46d {+05d 27' 46"}
  MOON_DIST:       117.12 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:      213.35, 32.00 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      130.76, -4.03 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Image.  
  COMMENTS:        If you have elected to receive attachments:  
  COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.  
  

  
• GCN notice #4103
  A. Parsons (GSFC), S. Barthelmy (GSFC), A. Beardmore (U. Leicester), P. Boyd (GSFC), D. Burrows (PSU), J. Cummings (GSFC/NRC), N. Gehrels (GSFC), O. Godet (U. Leicester), C. Gronwall (PSU), J. Kennea (PSU), H. Krimm (GSFC/USRA), F. Marshall (GSFC), D. Palmer (LANL), T. Sakamoto (GSFC) on behalf of the Swift team:
  At 18:28:09 UT, Swift-BAT triggered and located GRB 051016B (trigger=159994). The BAT on-board calculated location is RA,Dec 132.067d,+13.658d {08h 48m 16s,+13d 39' 27"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light curve shows a double peak structure with a total duration of at least 15 sec -- the slew started at T+15 sec, so determination of the full duration will have to wait until after the full data set is downlinked. The peak count rate was ~2200 counts/sec (15-150 keV), at ~1 and 3 seconds after the trigger. Initial inspection of the 4-channel lightcurves shows this burst to be soft.
  The spacecraft slewed promptly and the XRT began observing the GRB at 18:29:24 UT, 75 sec after the BAT trigger. An uncatalogued source was found by the on-board centroiding algorithm at

  RA(J2000)=08h 48m 27.6s
  Dec(J2000)=+13d 39' 25.5"
  

  with an uncertainty of 8 arcsec radius (90% containment). This position lies 168 arcsec from the center of the BAT error circle. The initial flux is approximately 4.6e-10 ergs/cm2/s. The count rate decreases during the first 100 seconds.
  UVOT began observing the field at 18:29:26 UT, 77 sec after the BAT trigger. The small image contains the entire XRT error circle. This image contains no new sources down to a limiting magnitude of 18.7 (3-sigma). No new source was seen in the list of sources from the entire UVOT field of view. E(B-V) in the direction of the XRT position is 0.037.
• GCN notice #4104
  L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), F. Marshall (FSFC), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), T. Takahashi (ISAS), J. Tueller (GSFC) on behalf of the Swift-BAT team:
  Using the full data set from the recent telemetry downlink, we report further analysis of Swift-BAT GRB 051016B (trigger #159994) (Parsons, et al., GCN 4103). The ground-analysis position is RA,Dec 132.120,+13.627 {08h 48m 28.8s,+13d 37' 38.4"} (J2000) with an uncertainty of 1.6 arcmin (radius, 90%, stat+sys). The parital coding fraction is 79 %. T90 is 4.0 +- 0.1 sec. The lightcurve consists of two overlapping peaks at T+0.3 and T+3.0 sec. Fitting a simple power law over the full interval from T-0.0 to T+4.6 sec, the photon index is 2.38 +/- 0.23 with a fluence of 1.7 +/- 0.2 X 10^-7 erg/cm^2. The peak flux in a 1-sec wide window starting at T+0.11 sec is 1.32 +/- 0.17 ph/cm^2/sec. All values are in the 15-150 keV band at the 90% confidence level.
• GCN notice #4105
  GRB 051016B : Optical follow-up at Lulin
  Y.T. Chen, Y.L. Wu, K-Y. Huang, W-H. Ip(NCU), Y. Urata (RIKEN) on behalf of EAFON report:
  " We have observed entire error region of GRB 051016B (Parsons et al. GCN 4103) with 1-m telescope at Lulin Observatory, Taiwan. Compare with DSS-2 images, we find a source in the Swift/XRT error region. The position is RA=08:48:27.81 DEC=+13:39:20.0. The source do not show significant variability during our observational period (1.5-2 hours after the burst). These 3-sigma limiting magnitudes derived from the USNO-B1.0 catalog are R=21.5.
  This message may be cited."
• GCN notice #4106
  S.Maeno,E.Sonoda,Y.Tokunaga,M.Yamauchi (University of Miyazaki)
  "We have observed the field covering the error circle of GRB 051016B (GCN4103) with the unfiltered CCD camera on the 30-cm telescopeat University of Miyazaki. The observation was started 19:16:07 UT on Oct.16. After co-adding a set of 25 images (19:16:07 - 19:59:25 UT) of 30 sec exposures, we have compared with the USNO A2.0 catalog. Preliminary analysis shows there is no new source brighter than 17.8 mag."
• GCN notice #4107
  A. J. Blustin (UCL-MSSL), A. Parsons (GSFC), S. T. Holland (GSFC), P. Meszaros, M. Chester (PSU), N. Gehrels (GSFC) on behalf of the Swift/UVOT team report:
  The Swift/UVOT began taking a settled exposure of the field of GRB 051016B 78 s after the trigger (Parsons et al. GCN 4103). A faint optical/UV source (not visible in the DSS) is detected in summed images at the position reported by Chen et al. (GCN 4105) at greater than 3 sigma in four of the UVOT filters; the magnitudes and upper limits are as follows:

  Filter  T_range(sec)  Exp(sec)  Mag/3-sig upper limit
  
  V       78-29720      2418      20.5 (upper limit)
  B       445-28020     2748      22.0 +/- 0.5
  U       391-35505     2507      20.9 +/- 0.3
  UVW1    337-34740     2796      21.7 +/- 0.4
  UVM2    283-33833     2798      21.0 (upper limit)
  UVW2    554-28928     2748      22.8 +/- 0.6
  

  The detection in UVW2 would imply that the redshift of the source is less than ~1.3.
  There was a further uncatalogued nearby UV-only source at (J2000 08:48:27.7 +13:39:12.0), outside the XRT error circle, with the following magnitudes:

  Filter   Mag
  
  UVW1     21.9 +/- 0.4
  UVM2     22.3 +/- 0.4
  UVW2     22.0 +/- 0.3
  

  Further data will be required to tell whether either source is variable.
  Uvot_cal@phoenix.astro.psu.edu https://phoenix.astro.psu.edu/mailman/listinfo/uvot_cal
• GCN notice #4108
  O. Godet (U. Leicester), A. Parsons (GSFC) K. Page, J. Osborne, A. Beardmore (U. Leicester), D. Burrows (PSU), N. Gehrels (GSFC) report on behalf the Swift XRT team:
  We have analysed the first four orbits of data from the Swift XRT observation of GRB051016B (Parsons et al., GCN 4103). The refined ground processed coordinates are :

   RA(J2000)  =  08h 48m 27.5s
   Dec(J2000) = +13d 39m 20.8s
  

  with an estimated uncertainty of 8 arcsecs radius (90% containment). This is 4.9 arcsecs away from the XRT position reported in Parsons et al.
  The XRT light curve shows a steep initial decline with a decay slope of 5.3+0.6/-0.7, followed by a break at ~T+ 200s to a shallower decay slope with a flare at ~T+409s superposed. At ~T+6000s, another break can be seen in the X-ray light-curve with a steeper decay slope of 0.9+/-0.2.
  The X-ray spectra show strong evolution in the early phase. The Windowed Timing (WT) data from the first orbit (from T+82s to T+107s) can be fit with an absorbed power-law with a photon index of 6.2+2.4/-1.5 and a column density excess of 4.8+/-2.0 E21 cm-2 over the Galactic column density of 3.66E+20 cm-2 in this direction. The Photon Counting (PC) spectrum from the first orbit (containing the flare) can be fit with an absorbed power-law with a photon index of 1.8+0.2/-0.4 and no absorption excess over the Galactic absorption. The PC spectrum of the second, third and fourth orbits can be fit by an absorbed power-law with a photon index of 1.5+/-0.1 and no absorption excess over the Galactic absorption.
  The observed 0.2-10 keV flux for the PC data from the second, third and fourth orbits (exposure time ~7600s, starting at ~T+3950s) was 3.82E-12 ergs cm**-2 s**-1, corresponding to an unabsorbed flux of 4.15E-12 ergs cm**-2 s**-1.
  Assuming the X-ray emission from the GRB continues to decline at the same rate (alpha~0.94), the predicted XRT count rate at T+24hrs is 0.0077 counts/s, which corresponds to an observed 0.2-10 keV flux of 4.2e-13 ergs cm**-2 s**-1.
• GCN notice #4110
  J. S. Bloom (UCB), H.-W. Chen, (Chicago), R. J. Foley (UCB), J. X. Prochaska (UCSC), report on behalf of a larger collaboration:
  "We observed the position of GRB 051016b (GCN 4103) with the NIRI instrument on the Gemini North Telescope beginning 20051017.59 UTC. In a stack of 45 minutes of exposure we detect several faint sources consistent with the XRT position (GCN 4108):

     A: 08:48:27.85 13:39:20.4
     B: 08:48:27.32 13:39:18.1
     C: 08:48:27.64 13:39:13.6
     D: 08:48:27.42 13:39:23.9
  

  The astrometry is derived assuming the nominal platescale of NIRI and based on the assumption that a bright galaxy (2MASS 1036.075258) is at position (J2000) 08:48:27.607 +13:39:02.67. Source A is 0.6" E and 0.4" N of an optical source reported by Maeno et al. (GCN 4106) and we thus associate this apparent IR point source (A) with the Lulin/UVOT source. We measure an isophotal mag of Ks[A] = 20.52 +/- 0.12 mag, assuming the 2MASS galaxy has magnitude of Ks = 15.209 mag. We make no claim of variability but source A is the most point-like of the 4 objects in the XRT error circle, so it is still a plausible afterglow candidate."
  We thank the Gemini observing staff for performing this ToO.
  This message may be cited.
• GCN notice #4111
  D. Kinoshita, Y.T. Chen, Y.L. Wu, K-Y. Huang, W-H. Ip(NCU), Y. Urata (RIKEN) on behalf of EAFON report:
  " We have observed the field of GRB 051016B (Parsons et al. GCN 4103) with Lulin 1m telescope at 17.845 (1.08 days after the burst). The R-band stacked image made from 5 x 300sec exposure do not show the candidate source reported by Chen et al (GCN 4105). These results suggest that the source located at RA=08:48:27.81 DEC=+13:39:20.0 is the afterglow of GRB 051016B.
  These images are available at http://140.115.34.82/~qq/grb/GRB051016B_LOT.jpg
  Our light curve around 1.5-2 hour do not show power-law decay as we reported (Chen et al GCN 4105). However, several early afterglows show platue phase such as GRB 041006 (Urata et al. ApJL submitted).
  This message may be cited."
  
• GCN notice #4112
  K. Torii (Osaka U.) reports on behalf of the ART collaboration:
  The error region of the soft GRB 051016b (Parsons et al. GCN 4103) was observed by the 14 inch Automated Response Telescope. VRcIc imaging started at 2005 October 16, 18:29:54 UT (105s after the trigger) and 60s integration was repeated.
  The optical afterglow candidate (Chen et al. GCN 4105) is not detected in our frames and the following limiting magnitudes for single and stacked frames are derived.

  ------------------------------------------
  StartUT	Filter	Limit	Nframes
  ------------------------------------------
  18:29:54 Rc	15.7R	1
  18:30:58 Ic	15.2I	1
  18:29:54 V+Rc+Ic 18.3R	9V+10Rc+10Ic
  ------------------------------------------
  

• GCN Circular #4185
  D. Sharapov, M. Ibrahimov (MAO), A.Pozanenko (IKI),V.Rumyantsev (CrAO) on behalf of larger GRB follow up collaboration report:
  We observed the error box of GRB051016B (Parsons et al, GCN 4103) with 1.5m telescope of Maidanak Astronomical Observatory. Set of R images were taken between Oct.16 (UT) 23:34 - 23:58. Afterglow candidate proposed by Chen (GCN 4105) and Kinoshita (GCN 4111) is detected in a stacked image. Preliminary photometry of the stacked image against of USNO A2.0 is following:

  Mid time,     Exposure, Filter, Mag.
  (UT)            (s)
  
  Oct.16.990   6x180   R       21.43 +/- 0.24
  

  The message may be cited.
• GCN Circular #4186
  A. M. Soderberg, E. Berger and E. Ofek report on behalf of the Caltech-NRAO-Carnegie collaboration:
  "We observed the optical afterglow position (GCN 4105) of GRB 051016B (GCN 4103) with the Low Resolution Imaging Spectrometer on the Keck I telescope on 2005 October 31.6 UT. We detect an extended source in the g and r filters which we identify as the host galaxy. In a 900 sec spectrum we detect emission lines of [O II] and Ne III, at a redshift of z=0.9364."