//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28236 SUBJECT: GRB 200809B: Fermi GBM Final Real-time Localization DATE: 20/08/09 15:51:48 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 15:41:27 UT on 9 Aug 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200809B (trigger 618680492.129862 / 200809654). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 359.8, Dec = -76.9 (J2000 degrees, equivalent to J2000 23h 59m, -76d 54'), with a statistical uncertainty of 3.4 degrees. The angle from the Fermi LAT boresight is 116.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200809654/quicklook/glg_skymap_all_bn200809654.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/bn200809654/quicklook/glg_healpix_all_bn200809654.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200809654/quicklook/glg_lc_medres34_bn200809654.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28237 SUBJECT: GRB 200809B: Swift/BAT-GUANO detection and arcminute localization DATE: 20/08/09 18:57:54 GMT FROM: Aaron Tohuvavohu at U Toronto Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Jamie Kennea (PSU) report: Swift/BAT did not trigger on GRB 200809B (T0: 2020-08-09 15:41:27 UTC, Fermi/GBM Team GCN 28236). The Fermi/GBM notice, distributed at T0+7 seconds triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, arXiv: 2005.01751). 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. Using the normal BAT imaging technique, we find the location of the GRB with an SNR of 10.4. The BAT ground-calculated position is RA, Dec = 15.9406, -73.8459 deg which is RA(J2000) = 01h 3m 45.7s Dec(J2000) = -73d 50’ 45.24” with an uncertainty of 4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 28.9%. This position is consistent with the Fermi GBM localization (GCN 28236). 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: 28238 SUBJECT: GRB 200809B: AstroSat CZTI detection DATE: 20/08/09 19:31:34 GMT FROM: Soumya Gupta at IUCAA/ASTROSAT S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (IUCAA/TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data showed the detection of a long GRB 200809B, which was also detected by Fermi GBM (GCN #28236) and Swift/BAT-GUANO (Tohuvavohu A. et al., GCN #28237). The source was clearly detected in the 40-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2020-08-09 15:41:26.500 UT. The measured peak count rate associated with the burst is 371 +/- 30 cts/s above the background in the combined data of four quadrants, with a total of 706 +/- 7 cts. The local mean background count rate was 537 +/- 1 cts/s. Using cumulative rates, we measure a T90 of 5.44 +/- 0.01 s. It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2020-08-09 15:41:25.000 UT. The measured peak count rate is 583 +/- 48 cts/s above the background in the combined Veto data of four quadrants, with a total of 785 +/- 19 cts. The local mean background count rate was 1637 +/- 2 cts/s. We measure a T90 of 5.72 +/- 0.45 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, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28239 SUBJECT: GRB 200809B: Swift ToO observations DATE: 20/08/09 19:32:22 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 200809B. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021026 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: 28240 SUBJECT: GRB 200809B: MAXI/GSC detection DATE: 20/08/10 03:27:53 GMT FROM: Satoshi Sugita at Aoyama Gakuin U. S. Sugita (AGU), H. Negoro, M. Nakajima, M. Aoki, K. Kobayashi, R. Takagi, K, Asakura, K, Seino (Nihon U.), T. Mihara, C. Guo, Y. Zhou, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, H. Nishida, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, R. Adachi, M. Niwano (Tokyo Tech), S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka (JAXA), Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi (Osaka U.), M. Yamauchi, K. Kurogi, K. Miike (Miyazaki U.), Y. Kawakubo (LSU), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), M. Sugizaki (NAOC) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 15:41:27 UT on 2020 Aug 9. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (15.369 deg, -73.867 deg) = (01 01 28, -73 52 01) (J2000) with a 90% C.L. statistical error of 0.38 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius). The position was consistent with GRB200809B (Fermi GBM: GCN 28236, Swift BAT: 28237). The X-ray flux averaged over the scan was 94 +- 17 mCrab (4.0-10.0keV, 1 sigma error). There was no significant excess flux in the next transit at 8/9 17:14 UT with an upper limit of 20 mCrab. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28241 SUBJECT: GRB 200809B: Swift-XRT afterglow detection DATE: 20/08/10 09:24:54 GMT FROM: Antonino D'Ai at IASF-PA M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), A.P. Beardmore (U. Leicester), 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 GRB 200809B (detected by Fermi/GBM, GCN 28236, Swift/BAT, GCN 28237, and MAXI/GSC, GCN 28240), collecting 3.1 ks of Photon Counting (PC) mode data between T0+14.0 ks and T0+41.4 ks. Two uncatalogued X-ray sources are detected, of which one ("Source 1") is believed to be the afterglow. Using 1323 s of PC mode data and 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 15.82953, -73.84557 which is equivalent to: RA (J2000): 01h 03m 19.09s Dec(J2000): -73d 50' 44.1" with an uncertainty of 4.5 arcsec (radius, 90% confidence). This position is 111 arcsec from the Swift/BAT position. The light curve can be modelled with a power-law decay with a decay index of alpha=1.7 (+2.0, -1.2). If the light curve continues to decay with a power-law decay index of 1.7, the count rate at T+24 hours will be 1.1 x 10^-3 count s^-1 The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00021026. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021026. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28242 SUBJECT: GRB 200809B: BOOTES-3/YA optical upper limit DATE: 20/08/10 12:36:13 GMT FROM: Youdong HU at IAA-CSIC Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado (IAA-CSIC), I. Carrasco and C. Perez del Pulgar (Univ. de Malaga), M. D. Caballero-Garcia (ASU-CAS, CZ) and R. Querel (NIWA), on behalf of a larger collaboration report: The 60cm BOOTES-3/YA robotic telescope at NIWA Lauder in Otago (New Zealand) gathered images covering the position of the position of the Swift/XRT X-ray afterglow of Fermi GRB 200809B (Fermi team. GCNC 28236). The first image (clear filter) was obtained starting at 09:58:18.81 UT 10th Aug (~ 18.4 hr after trigger). In the co-added image (5 exposures 60s each), no source is found at the position reported by Swift/XRT (Perri et al. GCNC 28241) down to 19.8 mag. Further observations are ongoing. We thank the staff at NIWA for its excellent support. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28243 SUBJECT: Fermi GRB 200809B: Global MASTER-Net observations report DATE: 20/08/10 17:15:10 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), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 200809B ( Fermi GBM team, GCN 28236) errorbox 27196 sec after notice time and 27226 sec after trigger time at 2020-08-09 23:15:13 UT, with upper limit up to 18.3 mag. Observations started at twilight. The observations began at zenith distance = 71 deg. The sun altitude is -15.3 deg. MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 200809B errorbox 1 days 4224 sec after notice time and 1 days 4253 sec after trigger time at 2020-08-10 16:52:21 UT, with upper limit up to 17.9 mag. Observations started at twilight. The observations began at zenith distance = 65 deg. The sun altitude is -9.8 deg. The galactic latitude b = -40 deg., longitude l = 307 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1416521 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 27316 | 2020-08-09 23:15:13 | MASTER-OAFA | (01h 02m 46.23s , -74d 39m 11.1s) | C | 180 | 18.0 | 27749 | 2020-08-09 23:22:26 | MASTER-OAFA | (01h 02m 47.91s , -74d 41m 22.8s) | C | 180 | 18.1 | 28173 | 2020-08-09 23:29:29 | MASTER-OAFA | (01h 02m 50.85s , -74d 39m 24.3s) | C | 180 | 18.2 | 28598 | 2020-08-09 23:36:34 | MASTER-OAFA | (01h 02m 54.25s , -74d 39m 46.9s) | C | 180 | 18.2 | 29023 | 2020-08-09 23:43:40 | MASTER-OAFA | (01h 02m 49.90s , -74d 39m 21.1s) | C | 180 | 18.0 | 29448 | 2020-08-09 23:50:44 | MASTER-OAFA | (01h 02m 50.04s , -74d 41m 20.6s) | C | 180 | 18.0 | 31197 | 2020-08-10 00:19:53 | MASTER-OAFA | (01h 02m 59.48s , -74d 39m 21.9s) | C | 180 | 18.3 | 31618 | 2020-08-10 00:26:55 | MASTER-OAFA | (01h 02m 53.37s , -74d 39m 10.0s) | C | 180 | 18.3 | 57541 | 2020-08-10 07:38:58 | MASTER-OAFA | (01h 02m 58.89s , -74d 41m 01.4s) | C | 180 | 16.8 | 57741 | 2020-08-10 07:42:17 | MASTER-OAFA | (01h 02m 56.20s , -74d 39m 38.4s) | C | 180 | 17.1 | 57940 | 2020-08-10 07:45:37 | MASTER-OAFA | (01h 02m 56.15s , -74d 41m 07.6s) | C | 180 | 17.4 | 58140 | 2020-08-10 07:48:57 | MASTER-OAFA | (01h 02m 59.81s , -74d 39m 27.4s) | C | 180 | 17.2 | 58340 | 2020-08-10 07:52:16 | MASTER-OAFA | (01h 02m 53.24s , -74d 40m 19.7s) | C | 180 | 16.6 | 58539 | 2020-08-10 07:55:36 | MASTER-OAFA | (01h 02m 53.57s , -74d 39m 21.4s) | C | 180 | 16.5 | 90684 | 2020-08-10 16:52:21 | MASTER-SAAO | (23h 43m 25.70s , -78d 04m 51.2s) | C | 60 | 17.5 | 90684 | 2020-08-10 16:52:21 | MASTER-SAAO | (00h 17m 44.42s , -78d 03m 55.8s) | C | 60 | 17.4 | 90763 | 2020-08-10 16:53:40 | MASTER-SAAO | (23h 43m 26.71s , -78d 04m 49.1s) | C | 60 | 17.6 | 90763 | 2020-08-10 16:53:40 | MASTER-SAAO | (00h 17m 45.09s , -78d 03m 53.9s) | C | 60 | 17.5 | 90843 | 2020-08-10 16:55:00 | MASTER-SAAO | (23h 40m 17.20s , -80d 05m 50.2s) | C | 60 | 17.7 | 90843 | 2020-08-10 16:55:00 | MASTER-SAAO | (00h 21m 30.38s , -80d 04m 52.9s) | C | 60 | 17.6 | 90923 | 2020-08-10 16:56:20 | MASTER-SAAO | (00h 15m 05.09s , -76d 03m 10.0s) | C | 60 | 17.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28244 SUBJECT: GRB 200809B: Fermi GBM detection DATE: 20/08/10 17:48:07 GMT FROM: Rachel Dunwoody at UCD R. Dunwoody (UCD), C. Fletcher (USRA), J. Mangan (UCD) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 15:41:27.13 UT on 09 August 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200809B (trigger 618680492 / 200809654) which was also detected by the Swift/BAT-GUANO (Tohuvavohu et al. 2020, GCN 28237) The Fermi GBM Final Real-time Localization (GCN 28236) is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 111 degrees. This burst was also independently detected by MAXI/GSC (GCN 28240) and AstroSat CZTI (GCN 28238). The GBM light curve consists of a single peak with a duration (T90) of about 17 s (50-300 keV). The time-averaged spectrum from T0 s to T0+17.6 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.5 +/- 0.3 and the cutoff energy, parameterized as Epeak, is 682 +/- 246 keV. The event fluence (10-1000 keV) in this time interval is (3.717 +/- 0.387)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.13 s in the 10-1000 keV band is 4.7 +/- 0.3 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/"