Gamma-ray Burst 170807A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Mon 07 Aug 17 21:56:28 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     766821,   Seg_Num: 0
  GRB_RA:          143.379d {+09h 33m 31s} (J2000),
                   143.587d {+09h 34m 21s} (current),
                   142.791d {+09h 31m 10s} (1950)
  GRB_DEC:         -17.329d {-17d 19' 44"} (J2000),
                   -17.408d {-17d 24' 28"} (current),
                   -17.107d {-17d 06' 23"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       1925 [cnts]    Image_Peak=117 [image_cnts]
  TRIGGER_DUR:     0.512 [sec] 
  TRIGGER_INDEX:   124     E_range: 25-100 keV
  BKG_INTEN:       21528 [cnts]
  BKG_TIME:        78956.50 SOD {21:55:56.50} UT
  BKG_DUR:         8 [sec]
  GRB_DATE:        17972 TJD;   219 DOY;   17/08/07
  GRB_TIME:        78969.11 SOD {21:56:09.11} UT
  GRB_PHI:         -116.67 [deg]
  GRB_THETA:        14.32 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     14.24 [sigma]
  IMAGE_SIGNIF:    7.17 [sigma]
  MERIT_PARAMS:     +1  +0  +0  -1  +2  -3 -100  +0 -83  +0 
  SUN_POSTN:       138.04d {+09h 12m 09s}  +16.17d {+16d 09' 54"}
  SUN_DIST:         34.02 [deg]   Sun_angle= -0.4 [hr] (East of Sun)
  MOON_POSTN:      319.72d {+21h 18m 53s}  -14.90d {-14d 54' 09"}
  MOON_DIST:       147.46 [deg]
  MOON_ILLUM:      100 [%]
  GAL_COORDS:      249.99, 24.59 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      152.20,-29.99 [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 = 174.82,-11.35 [deg]. 
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Mon 07 Aug 17 21:59:39 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     766821,   Seg_Num: 0
  GRB_RA:          143.379d {+09h 33m 31s} (J2000),
                   143.587d {+09h 34m 21s} (current),
                   142.791d {+09h 31m 10s} (1950)
  GRB_DEC:         -17.329d {-17d 19' 44"} (J2000),
                   -17.408d {-17d 24' 28"} (current),
                   -17.107d {-17d 06' 23"} (1950)
  GRB_DATE:        17972 TJD;   219 DOY;   17/08/07
  GRB_TIME:        78969.11 SOD {21:56:09.11} UT
  TRIGGER_INDEX:   124
  GRB_PHI:         -116.67 [deg]
  GRB_THETA:        14.32 [deg]
  DELTA_TIME:      19.00 [sec]
  TRIGGER_DUR:     0.512 [sec] 
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     14.24 [sigma]
  IMAGE_SIGNIF:    7.17 [sigma]
  LC_URL:          sw00766821000msb.lc
  SUN_POSTN:       138.04d {+09h 12m 09s}  +16.16d {+16d 09' 52"}
  SUN_DIST:         34.01 [deg]   Sun_angle= -0.4 [hr] (East of Sun)
  MOON_POSTN:      319.75d {+21h 19m 00s}  -14.90d {-14d 53' 47"}
  MOON_DIST:       147.47 [deg]
  MOON_ILLUM:      100 [%]
  GAL_COORDS:      249.99, 24.59 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      152.20,-29.99 [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 = 174.82,-11.35 [deg]. 
  

  
• GCN Circular #21420
  J.D. Gropp (PSU), S. D. Barthelmy (GSFC), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and A. Tohuvavohu (PSU) report on behalf of the Swift Team:
  At 21:56:09 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170807A (trigger=766821). Swift could not slew to the burst due to a Sun constraint. The BAT on-board calculated location is RA, Dec 143.379, -17.329 which is

     RA(J2000) = 09h 33m 31s
     Dec(J2000) = -17d 19' 44"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed two FRED structures with a total duration of about 40 sec. The peak count rate was ~2500 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 06:56 UT on 2017 October 03. There will thus be no XRT or UVOT data for this trigger before this time.
  Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu). 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 #21423
  A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), J. D. Gropp (PSU), H. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (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 170807A (trigger #766821) (Gropp et al., GCN Circ. 21420). The BAT ground-calculated position is RA, Dec = 143.434, -17.348 deg which is

    RA(J2000)  =  09h 33m 44.2s
    Dec(J2000) = -17d 20' 51.9"
  

  with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 92%.
  The mask-weighted light curve shows a multi-peaked structure that starts at ~T0 and ends at ~T+50 s. The two main peaks occur at ~T+1 s and ~T+30 s, respectively. T90 (15-350 keV) is 48.5 +- 11.7 sec (estimated error including systematics).
  The time-averaged spectrum from T-0.42 to T+53.08 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.82 +- 0.15. The fluence in the 15-150 keV band is 8.6 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.73 sec in the 15-150 keV band is 1.4 +- 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/766821/BA/