//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32985 SUBJECT: GRB 221126A: Fermi GBM Final Real-time Localization DATE: 22/11/26 13:18:03 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 13:07:29 UT on 26 Nov 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 221126A (trigger 691160854.94316 / 221126547). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 143.5, Dec = 13.1 (J2000 degrees, equivalent to J2000 09h 33m, 13d 05'), with a statistical uncertainty of 1.2 degrees. The angle from the Fermi LAT boresight is 22.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn221126547/quicklook/glg_skymap_all_bn221126547.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn221126547/quicklook/glg_healpix_all_bn221126547.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn221126547/quicklook/glg_lc_medres34_bn221126547.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32987 SUBJECT: GRB 221126A: Swift/BAT-GUANO detection outside the coded FOV DATE: 22/11/27 18:14:59 GMT FROM: Aaron Tohuvavohu at U Toronto Gayathri Raman (PSU), James DeLaunay (UAlabama), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU) report: Swift/BAT did not localize GRB 221126A onboard (T0: 2022-11-26T13:07:29 UTC, Fermi/GBM GCN 32985). The Fermi 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 BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu, arXiv:2111.01769), detects the burst with a sqrt(TS) of 11.9 in a 4.096 s analysis time bin. NITRATES results indicate a burst coming from outside the FOV, with DeltaLLHOut of -1. See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut. 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: 32990 SUBJECT: GRB 221126A: AstroSat CZTI detection DATE: 22/11/28 13:58:27 GMT FROM: Gaurav Waratkar at IIT,Bombay M. Dixit (IITB), V. Prasad (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of long GRB 221126A which was also detected by Fermi-GBM (GCN Cir. 32985) and Swift/BAT-GUANO (GCN Cir. 32987). The source was clearly detected in the 20-200 keV energy range. The light curve peaks at 2022-11-26 13:07:28.950 UTC. The measured peak count rate associated with the burst is 590.6 (+51.2, -55.0) counts/s above the background in the combined data of all quadrants, with a total of 2093 (+254, -271) counts. The local mean background count rate was 433.4 (+2.7, -3.0) counts/s. Using cumulative rates, we measure a T90 of 4.89 (+4.45, -1.03) s. It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2022-11-26 13:07:28.640 UTC. The measured peak count rate is 663.6 (+72.1, -79.1) counts/s above the background in the combined Veto data of all quadrants, with a total of 1770 (+234, -259) counts. The local mean background count rate was 1410.0 (+4.9, -5.4) counts/s. We measure a T90 of 4.18 (+1.11, -1.24) s from the cumulative Veto light curve. CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32992 SUBJECT: GRB 221126A: AGILE detection DATE: 22/11/28 17:26:49 GMT FROM: Claudio Casentini at INAF-IAPS C. Casentini, A. Ursi (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), A. Argan, M. Cardillo, Y. Evangelista, L. Foffano, E. Menegoni, G. Piano (INAF/IAPS), A. Addis, L. Baroncelli, A. Bulgarelli, A. Di Piano, V. Fioretti, G. Panebianco, N. Parmiggiani (INAF/OAS-Bologna), M. Romani (INAF/OA-Brera), M. Marisaldi (INAF/OAS-Bologna, Bergen University), M. Pilia, A. Trois (INAF/OA Cagliari), F. Longo (Uni. Trieste, INFN Trieste), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi) and P. Tempesta (TeleSpazio), report on behalf of the AGILE Team: The AGILE satellite detected the GRB 221126A at T0 = 2022-11-26 13:07:29 s (UTC), reported by Fermi/GBM (GCN #32985), Swift/BAT (GCN #32987) and AstroSat CZTI (GCN #32990). The burst is clearly visible in the AGILE scientific ratemeters of the AntiCoincidence, (AC-Top; 50-200 keV) detector. The event lasted about 6 s and it released a total number of 25792 counts in the AC-Top detector (above a background rate of 3388 Hz). The AGILE ratemeters light curves can be found at http://www.agilescienceapp.it/notices/GRB221126A.png. At the T0, the event was 51.82 deg off-axis. Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32994 SUBJECT: GRB 221126A: Fermi GBM observation DATE: 22/11/29 11:59:03 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 13:07:29.94 UT on 26 November 2022, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 221126A (trigger 691160854 / 221126547). This event was also observed by Swift/BAT-GUANO (GCN 32987), AstroSat CZTI (GCN 32990) and AGILE (GCN 32992). The GBM position is reported in the Fermi-GBM Final on-ground Localization (GCN 32985). The angle from the Fermi LAT boresight is 22 degrees. The GBM light curve shows a structured pulse with a duration (T90) of about 7 s (50-300 keV). The time-averaged spectrum from T0-0.90 s to T0+8.32 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.94 +/- 0.03 and the cutoff energy, parameterized as Epeak, is 194 +/- 8 keV The event fluence (10-1000 keV) in this time interval is (9.29 +/- 0.02)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+4.224 s in the 10-1000 keV band is 15.7 +/- 0.4 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 190 +/- 10 keV, alpha = -0.92 +/- 0.04 and beta = -3.1 +/- 0.6. 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/"