Gamma-ray Burst 220710A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #32375
  Aaron Tohuvavohu (U Toronto), James DeLaunay (UAlabama), Gayathri Raman (PSU), Jamie A. Kennea (PSU), report:
  Swift/BAT did not localize GRB 220710A onboard (T0: 2022-07-10T03:29:34 UTC, GECAM trig utn220710_032932_GECAMb).
  The GECAM notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1).
  Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.
  The burst is detected in BAT with a duration of ~25 seconds. The burst occurred during a Swift slew. The burst position is found with an image SNR of 20.
  The BAT position is RA, Dec = 221.592, 20.657 deg which is

     RA(J2000)  = 14h 46m 22.08s
     Dec(J2000) =  20d 39′ 25.2″
  

  with an uncertainty of 2 arcmin.
  XRT and UVOT follow-up has been requested Results of follow-up observations will be reported in future circulars.
  GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches.
• GCN Circular #32376
  P. A. Evans (U. Leicester) reports on behalf of the Swift team:
  Swift has initiated a ToO observation of the Swift/BAT-GUANO GRB 220710A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021509
  Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Swift/BAT-GUANO event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration.
  Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
  This circular is an official product of the Swift-XRT team.
• GCN Circular #32385
  A.P. Beardmore (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), J. D. Gropp (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), J.P. Osborne (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
  Swift-XRT has performed follow-up observations of the Swift/BAT-GUANO-detected burst GRB 220710A, collecting 4.4 ks of Photon Counting (PC) mode data between T0+242.5 ks and T0+287.4 ks.
  An uncatalogued X-ray source is detected consistent with being within 197 arcsec of the Swift/BAT-GUANO position and is above the 2SXPS 3-sigma upper limit at this position, and is therefore likely the GRB afterglow. The position of this source is RA, Dec=221.5668, +20.6576 which is equivalent to:

  RA (J2000): 14:46:16.03
  Dec(J2000): +20:39:27.3
  

  with an uncertainty of 8.3 arcsec (radius, 90% confidence). This position is 83 arcsec from the Swift/BAT-GUANO position. We cannot determine at the present time whether the source is fading.
  The results of the XRT-team automatic analysis of the likely afterglow are at https://www.swift.ac.uk/ToO_GRBs/00021509/Source3.php. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021509.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #32390
  A.A. Breeveld (UCL-MSSL) and N. J. Klingler (GSFC/UMBC/CRESTII) report on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of GRB 220710A 242493 s after the GECAM/GUANO trigger (Tohuvavohu et al., GCN Circ. 32375). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 32385) is detected in the UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:
  Filter T_start(s) T_stop(s) Exp(s) Mag
  white 242493 287404 4429 >22.9
  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.030 in the direction of the burst (Schlegel et al. 1998).