//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29188 SUBJECT: GRB 201228B: Fermi GBM Final Real-time Localization DATE: 20/12/28 15:32:09 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 15:21:45 UT on 28 Dec 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 201228B (trigger 630861710.97237 / 201228640). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 8.1, Dec = 50.7 (J2000 degrees, equivalent to J2000 00h 32m, 50d 42'), with a statistical uncertainty of 8.6 degrees. The angle from the Fermi LAT boresight is 20.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201228640/quicklook/glg_skymap_all_bn201228640.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201228640/quicklook/glg_healpix_all_bn201228640.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201228640/quicklook/glg_lc_medres34_bn201228640.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29189 SUBJECT: Fermi GRB 201228B: Global MASTER-Net observations report DATE: 20/12/28 16:45:14 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 201228B ( Fermi GBM team, GCN 29188) errorbox 1104 sec after notice time and 1136 sec after trigger time at 2020-12-28 15:40:42 UT, with upper limit up to 18.8 mag. Observations started at twilight. The observations began at zenith distance = 4 deg. The sun altitude is -15.3 deg. The galactic latitude b = -12 deg., longitude l = 120 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1513509 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1227 | 2020-12-28 15:40:42 | MASTER-Tavrida | (00h 39m 42.51s , +41d 18m 49.9s) | C | 180 | 18.8 | 1227 | 2020-12-28 15:40:42 | MASTER-Tavrida | (00h 39m 21.36s , +41d 17m 02.5s) | C | 180 | 18.2 | 1426 | 2020-12-28 15:44:02 | MASTER-Tavrida | (00h 39m 44.66s , +41d 20m 13.1s) | C | 180 | 18.8 | 1566 | 2020-12-28 15:47:21 | MASTER-Tavrida | (00h 39m 44.39s , +41d 20m 10.4s) | C | 60 | 18.2 | 1566 | 2020-12-28 15:47:21 | MASTER-Tavrida | (00h 39m 22.94s , +41d 18m 23.7s) | C | 60 | 18.4 | 2262 | 2020-12-28 15:58:58 | MASTER-Tavrida | (23h 56m 43.97s , +48d 01m 31.2s) | C | 60 | 17.9 | 2262 | 2020-12-28 15:58:58 | MASTER-Tavrida | (23h 56m 19.28s , +47d 59m 37.6s) | C | 60 | 17.8 | 2342 | 2020-12-28 16:00:17 | MASTER-Tavrida | (23h 56m 15.68s , +54d 03m 05.9s) | C | 60 | 17.2 | 2342 | 2020-12-28 16:00:17 | MASTER-Tavrida | (23h 55m 46.62s , +54d 01m 09.4s) | C | 60 | 17.3 | 2500 | 2020-12-28 16:02:56 | MASTER-Tavrida | (23h 56m 47.04s , +46d 02m 54.9s) | C | 60 | 17.9 | 2501 | 2020-12-28 16:02:56 | MASTER-Tavrida | (23h 56m 22.59s , +46d 00m 58.5s) | C | 60 | 17.9 | 2759 | 2020-12-28 16:07:14 | MASTER-Tavrida | (01h 05m 16.31s , +50d 04m 07.5s) | C | 60 | 18.2 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29985 SUBJECT: GRB 201228B: Swift/BAT-GUANO archival detection and arcminute localization DATE: 21/05/10 21:03:44 GMT FROM: Aaron Tohuvavohu at U Toronto James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU) report: Swift/BAT did not trigger on GRB 201228B (T0: 2020-12-28 15:21:45 UTC, Fermi/GBM trigger num 630861710, GCN 29188). 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 ~16 seconds. This burst was not localized in our low-latency analysis at the time. An updated and improved version of the targeted search pipeline was recently re-run on archival data and this burst was recovered. 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 27.88. 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 13.1. The BAT position is RA, Dec = 35.594, 56.015 deg which is RA(J2000) = 02h 22m 22.56s Dec(J2000) = +56d 00′ 54.0″ with an estimated uncertainty of 3 arcmin. This position is consistent with the Fermi GBM team localization (GCN 29188). 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: 30219 SUBJECT: GRB 201228B: Fermi GBM observation DATE: 21/06/12 00:13:12 GMT FROM: Cori Fletcher at USRA C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 15:21:45.97 UT on 28 December 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 201228B (trigger 630861710 / 201228640) which was also detected by the Swift/BAT-GUANO (DeLaunay et al. 2021, GCN 29985) The Fermi GBM Final Real-time Localization (GCN 29188) is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 39 degrees. The GBM light curve consists of single peak with a duration (T90) of about 30 s (50-300 keV). The time-averaged spectrum from T0-1.5 to T0+30.2 s is best fit by a Band function with Epeak = 49 +/- 14 keV, alpha = 0.8 +/- 1.2, and beta = -1.9 +/- 0.1. The event fluence (10-1000 keV) in this time interval is (2.199 +/- 0.251)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.8 s in the 10-1000 keV band is 1.3 +/- 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/"