Gamma-ray Burst 160827A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 27 Aug 16 15:47:40 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     710050,   Seg_Num: 0
  GRB_RA:          179.296d {+11h 57m 11s} (J2000),
                   179.509d {+11h 58m 02s} (current),
                   178.659d {+11h 54m 38s} (1950)
  GRB_DEC:         -29.159d {-29d 09' 32"} (J2000),
                   -29.252d {-29d 15' 06"} (current),
                   -28.881d {-28d 52' 50"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       23818 [cnts]    Image_Peak=460 [image_cnts]
  TRIGGER_DUR:     8.192 [sec] 
  TRIGGER_INDEX:   453     E_range: 15-50 keV
  BKG_INTEN:       170638 [cnts]
  BKG_TIME:        56711.22 SOD {15:45:11.22} UT
  BKG_DUR:         64 [sec]
  GRB_DATE:        17627 TJD;   240 DOY;   16/08/27
  GRB_TIME:        56805.24 SOD {15:46:45.24} UT
  GRB_PHI:         -52.69 [deg]
  GRB_THETA:        32.94 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     10.90 [sigma]
  IMAGE_SIGNIF:    8.32 [sigma]
  MERIT_PARAMS:     +1  +0  +0  +3  +1  -1 -100  +0 -71  +0 
  SUN_POSTN:       156.64d {+10h 26m 35s}   +9.75d {+09d 45' 04"}
  SUN_DIST:         44.80 [deg]   Sun_angle= -1.5 [hr] (East of Sun)
  MOON_POSTN:       97.58d {+06h 30m 20s}  +18.42d {+18d 25' 07"}
  MOON_DIST:        92.19 [deg]
  MOON_ILLUM:      23 [%]
  GAL_COORDS:      288.92, 32.23 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      191.90,-26.83 [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 = 37.63,-14.79 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 27 Aug 16 15:50:39 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     710050,   Seg_Num: 0
  GRB_RA:          179.296d {+11h 57m 11s} (J2000),
                   179.509d {+11h 58m 02s} (current),
                   178.659d {+11h 54m 38s} (1950)
  GRB_DEC:         -29.159d {-29d 09' 32"} (J2000),
                   -29.252d {-29d 15' 06"} (current),
                   -28.881d {-28d 52' 50"} (1950)
  GRB_DATE:        17627 TJD;   240 DOY;   16/08/27
  GRB_TIME:        56805.24 SOD {15:46:45.24} UT
  TRIGGER_INDEX:   453
  GRB_PHI:         -52.69 [deg]
  GRB_THETA:        32.94 [deg]
  DELTA_TIME:      38.00 [sec]
  TRIGGER_DUR:     8.192 [sec] 
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     10.90 [sigma]
  IMAGE_SIGNIF:    8.32 [sigma]
  LC_URL:          sw00710050000msb.lc
  SUN_POSTN:       156.65d {+10h 26m 35s}   +9.75d {+09d 45' 01"}
  SUN_DIST:         44.80 [deg]   Sun_angle= -1.5 [hr] (East of Sun)
  MOON_POSTN:       97.61d {+06h 30m 27s}  +18.42d {+18d 25' 06"}
  MOON_DIST:        92.16 [deg]
  MOON_ILLUM:      23 [%]
  GAL_COORDS:      288.92, 32.23 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      191.90,-26.83 [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 = 37.63,-14.79 [deg].  
  

  
• GCN Circular #19876
  K. L. Page (U Leicester) and S. D. Barthelmy (GSFC) report on behalf of the Swift Team:
  At 15:46:45 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160827A (trigger=710050). Swift did not slew due to observing constraint. The BAT on-board calculated location is RA, Dec 179.296, -29.159, which is

     RA(J2000)  =  11h 57m 11s
     Dec(J2000) = -29d 09' 32"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple overlapping peaks with a duration of about 30 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~8 sec after the trigger.
  Due to a Sun observing constraint, Swift cannot slew to the BAT position until 00:09 UT on 2016 November 14. There will thus be no XRT or UVOT data for this trigger before this time.
  Burst Advocate for this burst is K. L. Page (klp5 AT leicester.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 #19878
  T. N. Ukwatta (LANL) S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), (i.e. the Swift-BAT team):
  Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 160827A (trigger #710050) (Page, et al., GCN Circ. 19876). The BAT ground-calculated position is RA, Dec = 179.274, -29.178 deg, which is

     RA(J2000)  =  11h 57m 05.8s 
     Dec(J2000) = -29d 10' 40.9" 
  

  with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 48%.
  The mask-weighted light curve shows a few olverlapping peaks starting at ~T-5 sec, peaking at ~T+3 sec, and ending at ~T+13 sec. T90 (15-350 keV) is 13.3 +- 2.2 sec (estimated error including systematics).
  The time-averaged spectrum from T-5.81 to T+8.78 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.95 +- 0.25. The fluence in the 15-150 keV band is 4.0 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+2.49 sec in the 15-150 keV band is 0.7 +- 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/710050/BA/