Gamma-ray Burst 190816A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

   
  TITLE:           GCN/SWIFT NOTICE 
  NOTICE_DATE:     Fri 16 Aug 19 14:44:15 UT 
  NOTICE_TYPE:     Swift-BAT GRB Position 
  TRIGGER_NUM:     920783,   Seg_Num: 0 
  GRB_RA:          341.193d {+22h 44m 46s} (J2000), 
                   341.465d {+22h 45m 52s} (current), 
                   340.501d {+22h 42m 00s} (1950) 
  GRB_DEC:         -29.740d {-29d 44' 23"} (J2000), 
                   -29.636d {-29d 38' 10"} (current), 
                   -30.003d {-30d 00' 09"} (1950) 
  GRB_ERROR:       3.00 [arcmin radius, statistical only] 
  GRB_INTEN:       0 [cnts]    Image_Peak=1669 [image_cnts] 
  TRIGGER_DUR:     80.000 [sec]  
  TRIGGER_INDEX:   20000     E_range: 15-50 keV 
  BKG_INTEN:       0 [cnts] 
  BKG_TIME:        0.00 SOD {00:00:00.00} UT 
  BKG_DUR:         0 [sec] 
  GRB_DATE:        18711 TJD;   228 DOY;   19/08/16 
  GRB_TIME:        52944.57 SOD {14:42:24.57} UT 
  GRB_PHI:          55.47 [deg] 
  GRB_THETA:        29.66 [deg] 
  SOLN_STATUS:     0x13 
  RATE_SIGNIF:     0.00 [sigma]
  IMAGE_SIGNIF:    8.26 [sigma] 
  LC_URL:          sw00920783000msb.lc 
  SUN_POSTN:       145.79d {+09h 43m 10s}  +13.70d {+13d 41' 50"} 
  SUN_DIST:        158.46 [deg]   Sun_angle= 11.0 [hr] (West of Sun) 
  MOON_POSTN:      338.71d {+22h 34m 49s}  -13.11d {-13d 06' 41"} 
  MOON_DIST:        16.72 [deg] 
  MOON_ILLUM:      99 [%] 
  GAL_COORDS:       20.02,-62.12 [deg] galactic lon,lat of the burst (or transient) 
  ECL_COORDS:      331.08,-20.11 [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 an image 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 = 182.11,0.83 [deg].
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Fri 16 Aug 19 14:46:47 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     920783,   Seg_Num: 0
  GRB_RA:          341.193d {+22h 44m 46s} (J2000),
                   341.465d {+22h 45m 52s} (current),
                   340.501d {+22h 42m 00s} (1950)
  GRB_DEC:         -29.740d {-29d 44' 23"} (J2000),
                   -29.636d {-29d 38' 10"} (current),
                   -30.003d {-30d 00' 09"} (1950)
  GRB_DATE:        18711 TJD;   228 DOY;   19/08/16
  GRB_TIME:        52944.57 SOD {14:42:24.57} UT
  TRIGGER_INDEX:   20000
  GRB_PHI:          55.47 [deg]
  GRB_THETA:        29.66 [deg]
  DELTA_TIME:      0.00 [sec]
  TRIGGER_DUR:     80.000 [sec] 
  SOLN_STATUS:     0x13
  RATE_SIGNIF:     0.00 [sigma]
  IMAGE_SIGNIF:    8.26 [sigma]
  LC_URL:          sw00920783000msb.lc
  SUN_POSTN:       145.79d {+09h 43m 10s}  +13.70d {+13d 41' 50"}
  SUN_DIST:        158.46 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
  MOON_POSTN:      338.71d {+22h 34m 49s}  -13.11d {-13d 06' 41"}
  MOON_DIST:        16.72 [deg]
  MOON_ILLUM:      99 [%]
  GAL_COORDS:       20.02,-62.12 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      331.08,-20.11 [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 an image 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 = 182.11,0.83 [deg].  
  

  
• GCN Circular #25368
  K. L. Page (U Leicester), S. D. Barthelmy (GSFC), P. A. Evans (U Leicester), J.D. Gropp (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU), D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
  At 14:42:24 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190816A (trigger=920783). Swift did not slew due to an observing constraint. The BAT on-board calculated location is RA, Dec 341.193, -29.740, which is

     RA(J2000)  =  22h 44m 46s
     Dec(J2000) = -29d 44' 23"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a couple peaks with a total duration of about 30 sec. The peak count rate was ~600 counts/sec (15-350 keV), at ~3 sec after the trigger.
  Due to a Moon observing constraint, Swift cannot slew to the BAT position until 17:11 UT on 2019 August 17. 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/)
• GCN Circular #25399
  A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), A. Tohuvavohu (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and K. L. Page (U Leicester) report on behalf of the Swift-XRT team:
  We have analysed 3.8 ks of Photon Counting (PC) mode XRT data for the Swift/BAT-detected burst GRB 190816A (Page et al. GCN Circ. 25368), collected between T0+141.7 ks and T0+216.6 ks.
  One uncatalogued X-ray source has been detected consistent with being within 296 arcsec of the Swift/BAT position, it is below the RASS limit and shows no definitive signs of fading. Therefore, at the present time we cannot confirm this as the afterglow. Details of this source are given below:
  Source 4:

    RA (J2000.0):  341.1897  =  22:44:45.53
    Dec (J2000.0): -29.7577  =  -29:45:27.8
    Error: 4.8 arcsec (radius, 90% conf. [Enhanced position])
    Count-rate: (8.1 [+1.8, -1.7])e-3 ct s^-1   
    Distance: 64 arcsec from Swift/BAT position.
    Flux: (2.67 [+0.60, -0.56])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
  

  Three uncatalogued sources were also detected too far from the GRB position to be likely afterglow candidates.
  The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00920783.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #25405
  T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), K. L. Page (U Leicester), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team):
  Using the data set from T-862 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 190816A (trigger #920783) (Page et al., GCN Circ. 25368). The BAT ground-calculated position is RA, Dec = 341.183, -29.745 deg which is

     RA(J2000)  =  22h 44m 44.0s
     Dec(J2000) = -29d 44' 42.5"
  

  with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 30%.
  The mask-weighted light curve shows a weak multi-pulse structure that starts at ~ T-200 s and ends at ~T+340 s. T90 (15-350 keV) is 375.0 +- 92.9 sec (estimated error including systematics).
  The time-averaged spectrum from T-206.5 to T+341.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.62 +- 0.11. The fluence in the 15-150 keV band is 9.8 +- 0.6 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+151.57 sec in the 15-150 keV band is 1.3 +- 0.3 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/920783/BA/
• GCN Circular #25473
  A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), A. Tohuvavohu (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
  Swift-XRT has conducted further observations of the field of the Swift/BAT-detected burst GRB 190816A (Ukwatta et al. GCN Circ. 25405). The observations now extend from T0+141.7 ks to T0+723.4 ks. The source previously reported by D'Ai et al. (GCN Circ. 25399), "Source 4", is fading with 3-sigma significance, and is therefore likely the GRB afterglow. Using 267 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 341.18949, -29.75761 which is equivalent to:

  RA (J2000): 22h 44m 45.48s
  Dec(J2000): -29d 45' 27.4"
  

  with an uncertainty of 4.9 arcsec (radius, 90% confidence). This position is 64 arcsec from the Swift/BAT position. The source is fading with alpha >0.5.
  The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00920783. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00920783.
  This circular is an official product of the Swift-XRT team.