Gamma-ray Burst 111026A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 26 Oct 11 06:47:44 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     506291,   Seg_Num: 0
  GRB_RA:          244.275d {+16h 17m 06s} (J2000),
                   244.491d {+16h 17m 58s} (current),
                   243.362d {+16h 13m 27s} (1950)
  GRB_DEC:         -47.495d {-47d 29' 41"} (J2000),
                   -47.523d {-47d 31' 23"} (current),
                   -47.372d {-47d 22' 19"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       1239 [cnts]    Image_Peak=106 [image_cnts]
  TRIGGER_DUR:     0.256 [sec] 
  TRIGGER_INDEX:   123     E_range: 25-100 keV
  BKG_INTEN:       26572 [cnts]
  BKG_TIME:        24432.49 SOD {06:47:12.49} UT
  BKG_DUR:         8 [sec]
  GRB_DATE:        15860 TJD;   299 DOY;   11/10/26
  GRB_TIME:        24449.00 SOD {06:47:29.00} UT
  GRB_PHI:         -150.03 [deg]
  GRB_THETA:        14.69 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     13.03 [sigma]
  IMAGE_SIGNIF:    8.37 [sigma]
  MERIT_PARAMS:     +1  +0  +0  -2  +2  -1 -100  +1 -70  +0 
  SUN_POSTN:       210.31d {+14h 01m 14s}  -12.34d {-12d 20' 24"}
  SUN_DIST:         45.30 [deg]   Sun_angle= -2.3 [hr] (East of Sun)
  MOON_POSTN:      201.21d {+13h 24m 51s}  -13.15d {-13d 08' 51"}
  MOON_DIST:        49.72 [deg]
  MOON_ILLUM:      1 [%]
  GAL_COORDS:      334.84,  2.23 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      251.00,-25.74 [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 = 105.37,-7.20 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 26 Oct 11 06:51:05 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     506291,   Seg_Num: 0
  GRB_RA:          244.275d {+16h 17m 06s} (J2000),
                   244.491d {+16h 17m 58s} (current),
                   243.362d {+16h 13m 27s} (1950)
  GRB_DEC:         -47.495d {-47d 29' 41"} (J2000),
                   -47.523d {-47d 31' 23"} (current),
                   -47.372d {-47d 22' 19"} (1950)
  GRB_DATE:        15860 TJD;   299 DOY;   11/10/26
  GRB_TIME:        24449.00 SOD {06:47:29.00} UT
  TRIGGER_INDEX:   123
  GRB_PHI:         -150.03 [deg]
  GRB_THETA:        14.69 [deg]
  DELTA_TIME:      -50.00 [sec]
  TRIGGER_DUR:     0.256 [sec] 
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     13.03 [sigma]
  IMAGE_SIGNIF:    8.37 [sigma]
  LC_URL:          sw00506291000msb.lc
  SUN_POSTN:       210.31d {+14h 01m 14s}  -12.34d {-12d 20' 27"}
  SUN_DIST:         45.30 [deg]   Sun_angle= -2.3 [hr] (East of Sun)
  MOON_POSTN:      201.25d {+13h 24m 59s}  -13.16d {-13d 09' 31"}
  MOON_DIST:        49.69 [deg]
  MOON_ILLUM:      1 [%]
  GAL_COORDS:      334.84,  2.23 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      251.00,-25.74 [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 = 105.37,-7.20 [deg].  
  

  
• GCN Circular #12497
  W. H. Baumgartner (GSFC/UMBC), V. D'Elia (ASDC), P. A. Evans (U Leicester), C. Guidorzi (U Ferrara), O. M. Littlejohns (U Leicester), C. J. Mountford (U Leicester) and K. L. Page (U Leicester) report on behalf of the Swift Team:
  At 06:47:29 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 111026A (trigger=506291). A pointing constraint prevented Swift from slewing immediately to the burst. The BAT on-board calculated location is RA, Dec 244.275, -47.495 which is

     RA(J2000) = 16h 17m 06s
     Dec(J2000) = -47d 29' 41"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 1.5 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger.
  Due to a Sun observing constraint, Swift cannot slew to the BAT position until 14:29 UT on 2012 January 12. There will thus be no XRT or UVOT data for this trigger before this time.
  This burst is only two degrees off the Galactic plane and could be a Galactic transient.
  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 Circular #12507
  S. D. Barthelmy (GSFC), 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), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
  Using the data set from T-240 to T+963 sec from telemetry downlinks, we report further analysis of BAT GRB 111026A (trigger #506291) (Baumgartner, et al., GCN Circ. 12497). The BAT ground-calculated position is RA, Dec = 244.256, -47.435 deg, which is

     RA(J2000)  =  16h 17m 01.5s 
     Dec(J2000) = -47d 26' 05.1" 
  

  with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
  The mask-weighted light curve shows a couple overlapping pulses starting at ~T-0.5 and ending at ~T+4 sec. T90 (15-350 keV) is 3.62 +- 1.11 sec (estimated error including systematics).
  The time-averaged spectrum from T-0.09 to T+4.07 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.69 +- 0.21. The fluence in the 15-150 keV band is 1.7 +- 0.2 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band is 1.1 +- 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/506291/BA/
• GCN Circular #12512
  S. D. Barthelmy (GSFC), J. Norris (BSU), N. Gehrels (GSFC):
  We report the spectral lag analysis for GRB 111026A (GCN Circ. 12497) based on the BAT data. Using 64 ms binned light curves, the spectral lag for 15-25 keV to 50-100 keV is 27 +32/-40 msec. This value is not very constraining towards the shortness of this burst. And further, the fact that the burst is longer in the 15-25 keV band that in the higher energy band argues for a long burst assignment.