//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30297 SUBJECT: GRB 210622A: Fermi GBM Final Real-time Localization DATE: 21/06/22 01:42:57 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely SHORT GRB At 01:32:35 UT on 22 Jun 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210622A (trigger 646018360.939998 / 210622064). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 242.1, Dec = -14.1 (J2000 degrees, equivalent to J2000 16h 08m, -14d 05'), with a statistical uncertainty of 6.1 degrees. The angle from the Fermi LAT boresight is 82.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210622064/quicklook/glg_skymap_all_bn210622064.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210622064/quicklook/glg_healpix_all_bn210622064.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210622064/quicklook/glg_lc_medres34_bn210622064.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30302 SUBJECT: GRB 210622A: Swift/BAT-GUANO detection and arcminute localization of a long burst DATE: 21/06/22 13:59:39 GMT FROM: Aaron Tohuvavohu at U Toronto James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Gayathri Raman (PSU) report: Swift/BAT did not trigger on GRB 210622A (T0: 2021-06-22 01:32:35.9 UTC, Fermi/GBM GCN 30297). The Fermi/GBM 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 at least 25 seconds. We note this is different from the prompt GBM classification as ‘likely short’. The burst morphology consists of a first bright, short, hard, peak followed by longer emission with weaker flares. With a maximum likelihood analysis (DeLaunay et al. 2021, in prep.) on the event-mode data we detect a location for the burst with a square root of the test statistic, sqrt(TS), of 18.8. The sqrt(TS) behaves similarly to SNR. Using the normal BAT imaging technique, we find the same location for the GRB with an SNR of 8.1. The BAT position is RA, Dec = 233.117, -26.213 deg which is RA(J2000) = 15h 32m 28.10s Dec(J2000) = -26d 12′ 47.5″ with an estimated uncertainty of 2.5 arcmin. This position is consistent with the Ferm/GBM localization (GCN 30297). XRT and UVOT follow-up has been requested. Prompt followup by Swift is delayed due to visibility constraints. 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. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30306 SUBJECT: GRB 210622A: Fermi GBM detection DATE: 21/06/22 22:08:07 GMT FROM: Stephen Lesage at Fermi-GBM Team S. Lesage (UAH) and R. Hamburg (UAH) report on behalf of the Fermi GBM Team: "At 01:32:35.94 UT on 22 June 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 210622A (trigger 646018360 / 210622064) which was also detected by the Swift/BAT-GUANO (DeLaunay et al. 2021, GCN 30302) The Fermi GBM Final Real-time Localization (GCN 30297) is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 97 degrees. The GBM light curve consists of a single peak followed by some extended emission with a duration (T90) of about 40 s (50-300 keV). The time-averaged spectrum from T0 s to T0+39.4 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.8 +/- 0.2 and the cutoff energy, parameterized as Epeak, is 376 +/- 98 keV. The event fluence (10-1000 keV) in this time interval is (1.01 +/- 0.12)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.128 s in the 10-1000 keV band is 3.1 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog:https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page:https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30310 SUBJECT: GRB 210622A: Swift ToO observations DATE: 21/06/24 01:06:05 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the Swift/BAT-GUANO GRB 210622A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021452 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30317 SUBJECT: GRB 210622A: Swift-XRT observations DATE: 21/06/25 16:02:37 GMT FROM: Antonino D'Ai at IASF-PA A.P. Beardmore (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), 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 210622A (James DeLaunay et al. GCN Circ. 30302), collecting 4.5 ks of Photon Counting (PC) mode data between T0+171.2 ks and T0+221.6 ks. No X-ray sources have been detected consistent with being within 246 arcsec of the Swift/BAT-GUANO position. The 3-sigma upper limit in the field is 0.003 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.0e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum). An uncatalogued was detected, however this was too far from the GRB position to be the afterglow. The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00021452. This circular is an official product of the Swift-XRT team.