Gamma-ray Burst 170730A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:          GCN/INTEGRAL NOTICE
  NOTICE_DATE:    Sun 30 Jul 17 00:09:45 UT
  NOTICE_TYPE:    INTEGRAL Weak 
  TRIGGER_NUM:    7881,   Sub_Num: 0
  GRB_RA:         245.3492d {+16h 21m 24s} (J2000),
                  245.7345d {+16h 22m 56s} (current),
                  244.2572d {+16h 17m 02s} (1950)
  GRB_DEC:        -60.8960d {-60d 53' 45"} (J2000),
                  -60.9365d {-60d 56' 10"} (current),
                  -60.7775d {-60d 46' 38"} (1950)
  GRB_ERROR:      3.48 [arcmin, radius, statistical only]
  GRB_INTEN:      7.15 [sigma]
  GRB_TIME:       578.95 SOD {00:09:38.95} UT
  GRB_DATE:       17964 TJD;   211 DOY;   17/07/30
  SC_RA:          231.27 [deg] (J2000) 
  SC_DEC:         -59.55 [deg] (J2000) 
  SUN_POSTN:      129.45d {+08h 37m 47s}  +18.51d {+18d 30' 30"}
  SUN_DIST:       118.78 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
  MOON_POSTN:     209.67d {+13h 58m 40s}   -6.99d {-06d 59' 08"}
  MOON_DIST:       60.26 [deg]
  GAL_COORDS:     325.85, -7.75 [deg] galactic lon,lat of the burst
  ECL_COORDS:     254.92,-38.74 [deg] ecliptic lon,lat of the burst
  COMMENTS:       INTEGRAL GRB Coordinates -- this is the weak/subthreshold trigger notice.
  COMMENTS:       This notice may or may not be followed by a Wakeup/Refined/Offline notice.
  COMMENTS:       Time_Scale=20.0000 and Time_Error=20.0000.
  COMMENTS:       Possibly real GRB event (WEAK detection)
  

• GCN/BACODINE POSITION NOTICE
  

   
  TITLE:          GCN/INTEGRAL NOTICE
  NOTICE_DATE:    Sun 30 Jul 17 00:10:04 UT
  NOTICE_TYPE:    INTEGRAL Weak 
  TRIGGER_NUM:    7882,   Sub_Num: 0
  GRB_RA:         255.3900d {+17h 01m 34s} (J2000),
                  255.7750d {+17h 03m 06s} (current),
                  254.2971d {+16h 57m 11s} (1950)
  GRB_DEC:        -59.3229d {-59d 19' 22"} (J2000),
                  -59.3473d {-59d 20' 49"} (current),
                  -59.2501d {-59d 15' 00"} (1950)
  GRB_ERROR:      3.63 [arcmin, radius, statistical only]
  GRB_INTEN:      6.57 [sigma]
  GRB_TIME:       598.95 SOD {00:09:58.95} UT
  GRB_DATE:       17964 TJD;   211 DOY;   17/07/30
  SC_RA:          231.27 [deg] (J2000) 
  SC_DEC:         -59.55 [deg] (J2000) 
  SUN_POSTN:      129.45d {+08h 37m 47s}  +18.51d {+18d 30' 30"}
  SUN_DIST:       124.02 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
  MOON_POSTN:     209.67d {+13h 58m 41s}   -6.99d {-06d 59' 11"}
  MOON_DIST:       62.90 [deg]
  GAL_COORDS:     330.35,-10.53 [deg] galactic lon,lat of the burst
  ECL_COORDS:     260.81,-36.35 [deg] ecliptic lon,lat of the burst
  COMMENTS:       INTEGRAL GRB Coordinates -- this is the weak/subthreshold trigger notice.
  COMMENTS:       This notice may or may not be followed by a Wakeup/Refined/Offline notice.
  COMMENTS:       Time_Scale=20.0000 and Time_Error=20.0000.
  COMMENTS:       Possibly real GRB event (WEAK detection)
  

• GCN Circular #21390
  D.Gotz (CEA Saclay) on behalf of the IBAS Localization Team reports:
  the weak IBAS Alert nr. 7881 corresponds to a weak transient source lasting about 100 s, starting at 00:09:32 UT on July 30th 2017, localized at

  R.A: 245.3407 deg
  Dec: -60.8832 deg
  

  with an unceratinty of 2.5 arc min (90% c.l.).
  We prliminarly classify it as a GRB, but we cannot exclude that it is a new Galactic source due to its low Galactic latitude.
  Futher analysis is on-going.
  This message can be cited.
• GCN Circular #21392
  S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo, and J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:
  further analysis of the possible GRB 170730A detected as a subtrheshold alert by IBAS in the IBIS/ISGRI data at 00:09:20 UT of July 30, 2017 (Gotz et al. GCN 21390) yields the refined coordinates (J2000):

  R.A.= 245.2996 deg
  DEC.= -60.8866  deg
  

  with an uncertainty of 2 arcmin (90% c.l.).
  The burst lasted about 500 s, with a peak flux of about 0.6 photons/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range of about 1e-6 erg/cmq. The time averaged spectrum is consistent with a power law with photon index ~2
  A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html