//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28349 SUBJECT: GRB 200903A: Fermi GBM Final Real-time Localization DATE: 20/09/03 00:55:04 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 00:44:19 UT on 3 Sep 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200903A (trigger 620786664.250206 / 200903031). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 159.0, Dec = 54.9 (J2000 degrees, equivalent to J2000 10h 35m, 54d 53'), with a statistical uncertainty of 3.6 degrees. The angle from the Fermi LAT boresight is 58.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200903031/quicklook/glg_skymap_all_bn200903031.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/bn200903031/quicklook/glg_healpix_all_bn200903031.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200903031/quicklook/glg_lc_medres34_bn200903031.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28350 SUBJECT: GRB 200903A: Swift detection of a burst DATE: 20/09/03 01:06:11 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), J.D. Gropp (PSU), A. Y. Lien (GSFC/UMBC), M. J. Moss (GWU), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team: At 00:44:22 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200903A (trigger=994389). Swift did not slew immediately due to an observing constraint. The BAT on-board calculated location is RA, Dec 164.311, +50.501 which is RA(J2000) = 10h 57m 15s Dec(J2000) = +50d 30' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 30 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 14:33 UT on 2020 September 12. There will thus be no XRT or UVOT data for this trigger before this time. Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28351 SUBJECT: Swift GRB200903.03: Global MASTER-Net observations report DATE: 20/09/03 01:06:58 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) was pointed to the Swift GRB200903.03 (trigger No 994389,10h 57m 14.64s , +50d 30m 03.6s, R=0.05) errorbox 33 sec after notice time and 788 sec after trigger time at 2020-09-03 00:57:31 UT, with upper limit up to 14.0 mag. The observations began at zenith distance = 77 deg. The sun altitude is -22.2 deg. The galactic latitude b = 59 deg., longitude l = 158 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1432852 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 869 | MASTER-Tavrida | C | 160 | 14.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28357 SUBJECT: GRB 200903A: CALET Gamma-Ray Burst Monitor detection DATE: 20/09/03 12:06:27 GMT FROM: Valentin Pal'shin at AGU Y. Shimizu (Kanagawa U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The long soft GRB 200903A (Swift detection: Beardmore et al., GCN Circ. 28350; https://gcn.gsfc.nasa.gov/other/200903A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 00:44:17.477 UTC on 3 September 2020 (http://cgbm.calet.jp/cgbm_trigger/flight/1283129005/). The burst signal was seen by all CGBM detectors. The burst light curve shows a multi-peaked structure which starts at T+1.5 sec, peaks at T+5.9 sec, and ends at T+10.5 sec. The T90 and T50 durations measured by the SGM data are 8.2 +- 0.8 sec and 4.2 +- 0.8 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1283129005/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28360 SUBJECT: GRB 200903A: Swift-BAT refined analysis DATE: 20/09/03 18:48:09 GMT FROM: Amy Lien at GSFC T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 200903A (trigger #994389) (Beardmore et al., GCN Circ. 28350). The BAT ground-calculated position is RA, Dec = 164.313, 50.488 deg which is RA(J2000) = 10h 57m 15.1s Dec(J2000) = +50d 29' 15.7" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 67%. The mask-weighted light curve shows a precursor at ~T-19 s, followed by the main structure with several overlapping pulses that starts at ~T-5 s and ends at ~T+20 s. The burst went out of the BAT FOV at T+64 s. T90 (15-350 keV) is 24.15 +- 7.68 sec (estimated error including systematics). The time-averaged spectrum from T-19.18 to T+22.13 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.15 +- 0.28, and Epeak of 107.4 +- 65.8 keV (chi squared 45.20 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.8 +- 0.1 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+0.14 sec in the 15-150 keV band is 3.8 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.56 +- 0.07 (chi squared 51.88 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/994389/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28362 SUBJECT: GRB 200903A: Fermi GBM detection DATE: 20/09/04 00:48:15 GMT FROM: Stephen Lesage at Fermi-GBM Team S. Lesage (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 00:44:19.25 UT on 3 September 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200903A (trigger 620786664 / 200903031) which was also detected by the Swift/BAT (A. P. Beardmore et al. 2020, GCN 28350). The Fermi GBM Final Real-time Localization (GCN 28349) is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is ~61 degrees. The GBM light curve shows a single bright peak with a duration (T90) of about 26.9 s (50-300 keV). The time-averaged spectrum from T0-5.4 s to T0+21.5 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.9 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 111.4 +/- 8.9 keV. The event fluence (10-1000 keV) in this time interval is (4.6 +/- 0.2)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+3.3 s in the 10-1000 keV band is 6.03 +/- 0.24 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/"