Gamma-ray Burst 170424A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #21307
  S. L. Xiong, C. K. Li, J. Y. Liao, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao, A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), M. Gao (IHEP), T. P. Li (IHEP/THU), M. S. Li, H. W. Liu, F. J. Lu, L. M. Song, W. H. Tao, H. Y. Wang, X. Y. Wen, M. Wu, H. Xu, Y. P. Xu, C. M. Zhang, F. Zhang, J. Zhang, T. Zhang, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team:
  During the commissioning phase, at 2017-07-08T01:06:11.25 (T0), Insight-HXMT detected GRB 170708A (trigger ID: HEB170708045) in a routine search of the data, which was also observed by the Fermi/GBM (Trig# 521168776) and SPI-ACS (Trig time 2017-07-08T01:06:10.708).
  The Insight-HXMT light curve consists of a single pulse with a duration (T90) of 0.22 s measured from T0-0.05 s. The 50-ms peak rate, measured from T0+0 s, is 3553.6 cnts/sec. The total counts from this burst is 369 counts.
  All measurements above are made with the CsI detectors operating in the GRB mode, in which the energy range is increased to about 200 - 3000 keV (record energy) , compared to the normal mode of 80 - 800 keV. Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope.
  URL_LC: http://www.hxmt.org/images/GRB/HEB170708045_lc.jpg
  This is a weak short burst. The detection significance of Insight-HXMT is ~10 sigma. The burst emission is seen up to ~1 MeV.
  The analysis results presented above are preliminary; final results will be published elsewhere.
  Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org/index.php/enhome .
  
• GCN Circular #21314
  D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova, and T. Cline on behalf of the Konus-Wind team,
  K. Hurley, on behalf of the IPN,
  V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein, on behalf of the Fermi GBM team, and
  A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report:
  A short-duration GRB 170708A (Xiong et al., GCN Circ. 21307) has been detected by Konus-Wind, Fermi (GBM; trigger 521168776), and INTEGRAL (SPI-ACS), so far, at about 3971 s UT (01:06:11).
  We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:

    ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
     335.835 (22h 23m 20s) +19.798 (+19d 47' 51")
    Corners:
     333.909 (22h 15m 38s) +21.274 (+21d 16' 26")
     336.055 (22h 24m 13s) +19.813 (+19d 48' 47")
     337.608 (22h 30m 26s) +18.268 (+18d 16' 06")
     335.615 (22h 22m 28s) +19.781 (+19d 46' 52")
    ---------------------------------------------
  

  The error box area is 2441 sq. arcmin, and its maximum dimension is 4.60 deg (the minimum one is 16.6 arcmin). The Sun distance was 116 deg.
  This box may be improved.
  A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB170708_T03974/IPN/
  The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
• GCN Circular #21330
  D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, A. Tsvetkova, A. Lysenko, A.Kozlova, and T. Cline on behalf of the Konus-Wind team, report:
  The short-duration GRB 170708A (IPN triangulation: Svinkin et al., GCN Circ. 21314; Insight-HXMT detection: Xiong et al., GCN Circ. 21307) triggered Konus-Wind at T0=3974.665 s UT (01:06:14.665).
  The burst light curve shows a single pulse with a total duration of ~0.2 s. The emission is seen up to ~500 keV.
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB170708_T03974/
  As observed by Konus-Wind, the burst had a fluence of 8.04(-1.2,+1.4)x10^-7 erg/cm2, and a 16-ms peak flux, measured from T0-0.014 s, of 1.48(-0.37,+0.40)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-integrated 3-channel spectrum of the burst, measured from T0-0.014 s to T0+0.224 s, can be modelled by an exponentially cut off power law: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.94(-0.30,+0.42) and Ep = 269(-75,+147) keV.
  All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.