//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30129 SUBJECT: GRB 210605B: Fermi GBM Final Real-time Localization DATE: 21/06/05 15:06:08 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 14:55:58 UT on 5 Jun 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210605B (trigger 644597763.075646 / 210605622). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 15.1, Dec = -6.5 (J2000 degrees, equivalent to J2000 01h 00m, -6d 30'), with a statistical uncertainty of 3.8 degrees. The angle from the Fermi LAT boresight is 18.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210605622/quicklook/glg_skymap_all_bn210605622.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/bn210605622/quicklook/glg_healpix_all_bn210605622.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210605622/quicklook/glg_lc_medres34_bn210605622.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30130 SUBJECT: GRB 210605B: Swift/BAT-GUANO detection and arcminute localization DATE: 21/06/06 00:21:21 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 210605B (T0: 2021-06-06 14:55:58 UTC, Fermi/GBM GCN 31029). 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 20 seconds. The burst occurred during a Swift slew. The position of the burst was found with SNR of 8.4 using a novel slew image mosaicing procedure (DeLaunay et al. 2021, in prep.), and so the positional uncertainty is not yet well characterized. The BAT position is RA, Dec = 15.732, -6.467 deg which is RA(J2000) = 01h 02m 55.68s Dec(J2000) = -6d 28′ 1.2″ with an estimated uncertainty of 5 arcmin. This position is consistent with the Ferm/GBM localization (GCN 31029). 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: 30133 SUBJECT: GRB 210605B: Swift ToO observations DATE: 21/06/06 11:33:22 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 GRB 210605B. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021450 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 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: 30146 SUBJECT: GRB 210605B: Swift-XRT observations DATE: 21/06/07 18:29:21 GMT FROM: Boris Sbarufatti at PSU A. D'Ai (INAF-IASFPA), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB) 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-detected burst GRB 210605B (James DeLaunay et al. GCN Circ. 30130), collecting 5.0 ks of Photon Counting (PC) mode data between T0+74.2 ks and T0+96.6 ks. One uncatalogued X-ray sources has been detected, however it is not above the RASS limit or shows definitive signs of fading. Therefore, at the present time we cannot confirm if this source is the afterglow. Details of the source are given below: Source 1: RA (J2000.0): 15.7456 = 01:02:58.95 Dec (J2000.0): -6.4290 = -06:25:44.3 Error: 5.7 arcsec (radius, 90% conf.) Count-rate: (2.94 [+1.05, -0.86])e-3 ct s^-1 Distance: 145 arcsec from Swift/BAT position. Flux: (9.3 [+3.3, -2.7])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV) The field has been previously observed by XRT for the Swift Gravitational Wave Galaxy Survey (https://www.swift.ac.uk/SGWGS/). No source was detected at this position on a 5.3 ks integrated exposure, down to a 3-σ upper limit of 2.7 e-3 ct s^-1. A catalogued source and a spurious source caused by Earth limb contamination were also detected. 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/00021450. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30209 SUBJECT: GRB 210605B: Fermi GBM detection DATE: 21/06/11 20:57:40 GMT FROM: Suraj Poolakkil at UAH S. Poolakkil (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 14:55:58.08 UT on 5 June 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 210605B (trigger 644597763 / 210605622) which was also detected by the Swift/BAT-GUANO (DeLaunay et al. 2021, GCN 30130) The Fermi GBM Final Real-time Localization (GCN 30129) is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 19 degrees. The GBM light curve consists of multiple peaks followed by some extended emission with a duration (T90) of about 110 s (50-300 keV). The time-averaged spectrum from T0-3.07 s to T0+113.66 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.78 +/- 0.08 and the cutoff energy, parameterized as Epeak, is 150 +/- 11 keV. The event fluence (10-1000 keV) in this time interval is (10.12 +/- 0.44)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+26.36 s in the 10-1000 keV band is 3.3 +/- 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: 30234 SUBJECT: GRB 210605B: Swift-XRT afterglow detection DATE: 21/06/14 14:06:06 GMT FROM: Aaron Tohuvavohu at U Toronto A. D'Ai (INAF-IASFPA), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has conducted further observations of the field of the Swift/BAT-GUANO detected burst GRB 210605B (James DeLaunay et al. GCN Circ. 30130). The observations now extend from T0+74.3 ks to T0+734.1 ks. Of the sources reported by D'Ai et al. (GCN Circ. 30146), "Source 1" is fading with 2.5 sigma significance and thus is believed to be the GRB afterglow. The position of this source is RA, Dec=15.7456, -6.4290 which is equivalent to: RA (J2000): 01:02:58.95 Dec(J2000): -06:25:44.3 with an uncertainty of 5.7 arcsec (radius, 90% confidence). This position is 2.4 arcmin from the Swift/BAT position. The light curve can be modelled with a power-law decay with a decay index of alpha=0.8 (+0.7, -0.4). The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00021450. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021450. This circular is an official product of the Swift-XRT team.