CGBM observations of high bursting activity of SGR 1935+2154
Abstract
The CALET Gamma-ray Burst Monitor (CGBM) has been observing high bursting activity of SGR 1935+2154 since the CGBM trigger at ~18:32 UTC on 27 April 2020. No real-time CGBM GCN notice was distributed about this trigger because the real-time communication from the ISS was off (loss of signal). This trigger followed the Swift and Fermi-GBM triggers on bursts from SGR 1935+2154 at ~18:20 UTC reported in GCNs 27657, 27659, and 27660 (at this time CGBM HV was off). The CGBM data display a burst cluster along with multiple short bright bursts. The first CGBM trigger was shortly followed by another CGBM trigger at 18:46:08.675 UTC (trigger 1272047979: http://cgbm.calet.jp/cgbm_trigger/flight/1272047979/index.html) with several intense bursts. Additional two unalerted CGBM triggers with multiple short intense soft bursts were detected at ~20:15 UTC and ~21:49 UTC on 2020-04-27. After this, CGBM on-board trigger was disabled because it reached the maximum numbers of the accepted triggers. Further episodes of SGR activity were observed in CGBM TH data at ~23:18 UTC on 2020-04-27 and at ~00:43 - 00:57 UTC on 2020-04-28. Totally several tens of short bright SGR bursts have been detected by CGBM so far. So, SGR 1935+2154 did enter a new phase of activity as was suggested in GCN 27623.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- April 2020
- Bibcode:
- 2020GCN.27663....1R