GRB 220710A
GCN Circular 32375
Subject
GRB 220710A: Swift/BAT-GUANO arcminute localization
Date
2022-07-12T20:58:22Z (3 years ago)
From
Aaron Tohuvavohu at U Toronto <aaron.tohu@gmail.com>
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
Subject
GRB 220710A: Swift ToO observations
Date
2022-07-12T22:50:11Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
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
Subject
GRB 220710A: Swift-XRT afterglow detection
Date
2022-07-13T16:37:22Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
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
Subject
GRB 220710A: Swift/UVOT Upper Limits
Date
2022-07-14T06:28:25Z (3 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
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).