//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28577 SUBJECT: GRB 201008A: BALROG localization (Fermi Trigger 623846261 / GRB 201008443) DATE: 20/10/08 11:04:12 GMT FROM: Jochen Greiner at MPE,Garching F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 623846261 at 10:37:36 on 08 Oct. 2020 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position (1 sigma statistical errors) is: RA(2000.0) = 167.1+/-4.3 deg Decl.(2000.0) = 42.1+/-3.9 deg We estimate an additional systematic error of 2 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB201008443/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB201008443/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB201008443/json //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28583 SUBJECT: GRB 201008A: Swift/BAT-GUANO detection and possible arcminute localization DATE: 20/10/08 22:41:45 GMT FROM: James DeLaunay at PSU James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Jamie Kennea (PSU), Peter Veres (UAH) report: Swift/BAT did not trigger on GRB 201008A (T0: 2020-10-08 10:37:36 UTC, Fermi/GBM Team TRIGGER 623846261). 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 T90 duration of ~2.5 seconds. With a maximum likelihood analysis (DeLaunay et al. 2020, 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 13.22. The sqrt(TS) behaves similarly to SNR. Using the normal BAT imaging technique, we find the location of the GRB with an SNR of 4.2. Since this is a low significance detection near the edge of the coded field of view there is a chance that this localization may be incorrect. The BAT ground-calculated position is RA, Dec = 161.744, 46.101 deg which is RA(J2000) = 10h 46m 58.56s Dec(J2000) = 46d 06’ 03.6” with an uncertainty of 5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 3.5%. This position is consistent with the Fermi GBM localization ( https://gcn.gsfc.nasa.gov/other/623846261.fermi) and BALROG localization (GCN 28577). XRT and UVOT follow-up has been triggered. 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: 28585 SUBJECT: GRB 201008A: Swift ToO observations DATE: 20/10/08 23:40:25 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 Fermi/GBM GRB 201008A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021034 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 Fermi/GBM 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: 28587 SUBJECT: GRB 201008A: Swift-XRT observations DATE: 20/10/09 08:43:38 GMT FROM: Phil Evans at U of Leicester K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/GBM and Swift/BAT-GUANO detected burst GRB 201008A (DeLaunay et al. GCN Circ. 28583), collecting 4.5 ks of Photon Counting (PC) mode data between T0+46.9 ks and T0+60.1 ks. Two uncatalogued X-ray sources have been detected consistent with being within 296 arcsec of the BAT/GUANO position, however none of them is above the RASS limit or shows definitive signs of fading. Therefore, at the present time we cannot identify which, if any, is the afterglow. Details of these sources are given below: Source 1: RA (J2000.0): 161.7543 = 10:47:1.02 Dec (J2000.0): +46.1475 = +46:08:51.1 Error: 5.1 arcsec (radius, 90% conf.) Count-rate: (1.79 [+1.09, -0.80])e-3 ct s^-1 Distance: 169 arcsec from BAT position. NB, this position is consistent with SDSS J104701.20+460848.8, a likely quasar in the SDSS Quasar Catalogue. If this association and ID is accurate, this source is unlikely to be related to the GRB. Source 4: RA (J2000.0): 161.8588 = 10:47:26.10 Dec (J2000.0): +46.1019 = +46:06:06.9 Error: 4.8 arcsec (radius, 90% conf.) Count-rate: (4.1 [+1.3, -1.1])e-3 ct s^-1 Distance: 286 arcsec from BAT position. Flux: (1.68 [+0.52, -0.44])e-10 erg cm^-2 s^-1 (observed, 0.3-10 keV) Two uncatalogued sources were also detected too far from the GRB position to be likely afterglow candidates. 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/00021034. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28648 SUBJECT: GRB 201008A: Swift-XRT afterglow detection DATE: 20/10/16 07:33:35 GMT FROM: Phil Evans at U of Leicester K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU) 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 Fermi/GBM and Swift-BAT/GUANO detected burst GRB 201008A (DeLaunay et al. GCN Circ. 28583). The observations now extend from T0+47.0 ks to T0+650.8 ks. Of the sources reported by Page et al. (GCN Circ. 28587), "Source 4" is fading with 3-sigma significance, and is therefore likely the GRB afterglow. The position of this source is RA, Dec=161.8588, +46.1019 which is equivalent to: RA (J2000): 10:47:26.10 Dec(J2000): +46:06:06.9 with an uncertainty of 4.8 arcsec (radius, 90% confidence). This position is 4.8 arcmin from the BAT/GUANO position. The source is fading with alpha >0.8. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00021034. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021034. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30242 SUBJECT: GRB 201008A: Fermi GBM observation DATE: 21/06/16 17:27:21 GMT FROM: Elisabetta Bissaldi at INFN,Bari E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 10:37:36.71 UT on 8 October 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 201008A (trigger 623846261 / 201008443), which was also detected by the Swift/BAT-GUANO (DeLaunay et al. 2020, GCN 28583). The Fermi GBM Final Real-time Localization is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 60 degrees. The GBM light curve consists of a multi-peaked emission episode with a duration (T90) of about 2 s (50-300 keV). The time-averaged spectrum from T0-0.26 s to T0+2.11 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.80 +/- 0.13 and the cutoff energy, parameterized as Epeak, is 166 +/- 21 keV. The event fluence (10-1000 keV) in this time interval is (1.17 +/- 0.09)E-06 erg/cm^2. The 64-ms peak photon flux measured starting from T0+1.28 s in the 10-1000 keV band is 7.3 +/- 1.3 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/"