//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28066 SUBJECT: GRB 200704A: Insight-HXMT/HE detection DATE: 20/07/06 06:03:09 GMT FROM: Qi Luo at IHEP Q. Luo, Y. G. Zheng, C. Cai, S. Xiao, Q. B. Yi, W. C. Xue, Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: At 2020-07-04T09:27:38.35 (T0), Insight-HXMT/HE detected GRB 200704A (trigger ID: HEB200704394) in a routine search of the data, which also triggered Konus-Wind. The Insight-HXMT/HE light curve mainly consists of multiple pulses with a duration (T90) of 39.119 s measured from T0-0.070 s. The 1-ms peak rate, measured from T0-0.076 s, is 2352 cnts/sec. The total counts from this burst is 22227 counts. URL_LC: http://twiki.ihep.ac.cn/pub/HXMT/GRBList/HEB200704394_lc.jpg All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (deposited energy). 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. 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30381 SUBJECT: GRB 200704A: possible local hosts DATE: 21/07/05 18:32:51 GMT FROM: Andrew Levan at U.of Leicester A.J. Levan (Radboud), S. Campana (INAF-OAB), D.A. Kann (HETH/IAA-CSIC), P D'Avanzo (INAF-OAB) report: “We note that the Swift XRT localisation (D’Ai et al. GCN 30379) of GRB 210704A detected by Fermi-LAT, Fermi-GBM (Kunzweiler et al. GCN 30369, Malacaria et al. GCN 30380), AGILE (Ursi et al. GCN 30722) and AstroSat (Prasad et al. GCN 30378) lies in a significant galaxy overdensity. Of particular note, the source localisation overlaps the galaxy cluster 400d J1036+5713 at z=0.203. Although there are no apparent galaxies within the XRT localisation visible in the PanSTARRS 3pi imaging of the field, there are numerous likely members of this cluster within a few arcseconds. Furthermore, an even brighter foreground galaxy WISEA J103604.24+571327.7 lies offset approximately 30” from the XRT position and has a reported redshift of z=0.0817. This galaxy has I=15.962 +/- 0.007 (and absolute magnitude around -22). Its projected physical offset from the burst position is approximately 45 kpc. Although this offset is significant, the probability of chance alignment remains small. The burst itself appears dominated by a short-spike, with a fainter tail of emission, and these possible host galaxies are consistent with the hosts and locations of short GRBs (and not of long GRBs). At z=0.203 (or z=0.0891) the isotropic equivalent energy would be E_iso ~ 2e51 erg (or E_iso ~ 3e50 erg at z=0.0891), consistent with SGRBs. Observations to search for the optical afterglow or possibly rising kilonova emission are strongly encouraged. “