//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28334 SUBJECT: Swift GRB200901.16: Global MASTER-Net observations report DATE: 20/09/01 03:54:13 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-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) was pointed to the Swift GRB200901.16 (trigger No 994143,04h 07m 01.92s , -59d 52m 48.0s, R=0.05) errorbox 25 sec after notice time and 46 sec after trigger time at 2020-09-01 03:48:18 UT, with upper limit up to 16.9 mag. The observations began at zenith distance = 65 deg. The sun altitude is -64.8 deg. The galactic latitude b = -43 deg., longitude l = 271 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1431471 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 52 | MASTER-OAFA | C | 10 | 16.4 | 81 | MASTER-OAFA | C | 10 | 16.5 | 116 | MASTER-OAFA | C | 20 | 16.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28335 SUBJECT: GRB 200901A: Swift detection of a burst DATE: 20/09/01 03:56:30 GMT FROM: David Palmer at LANL K. K. Simpson (PSU), S. D. Barthelmy (GSFC), J.D. Gropp (PSU), N. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), B. Sbarufatti (PSU) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 03:47:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200901A (trigger=994143). Swift did not slew immediately due to an observing constraint. The BAT on-board calculated location is RA, Dec 61.758, -59.880 which is RA(J2000) = 04h 07m 02s Dec(J2000) = -59d 52' 47" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 50 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+47.5 minutes. There will be no XRT or UVOT data until this time. This source lies within the current (Sector 29) field-of-view of TESS camera 3. Burst Advocate for this burst is K. K. Simpson (kira.simpson1984 AT gmail.com). 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: 28336 SUBJECT: GRB 200901A: Swift-XRT observations DATE: 20/09/01 05:22:59 GMT FROM: Phil Evans at U of Leicester D.N. Burrows (PSU), J.A. Kennea (PSU), M. Perri (ASDC), G. Tagliaferri (INAF-OAB), P.A. Evans (U. Leicester) and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team: The XRT began observing the field of GRB 200901A at 04:38:21.9 UT, 3050.4 seconds after the BAT trigger. No source was detected in 1.9 ks of promptly downlinked data, which covered 54% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28340 SUBJECT: GRB 200901A: Fermi GBM observation DATE: 20/09/01 18:08:49 GMT FROM: Peter Veres at UAH P. Veres, R. Hamburg and C. Meegan (all UAH) report on behalf of the Fermi GBM Team: "At 03:47:27.62 UT on 1 September 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered on GRB 200901A (trigger 620624852 / 200901158) which was also detected by the Swift/BAT (Simpson et al., GCN 28335). The GBM on-ground location is consistent with the Swift position. The event was classified as particle activity by the flight software, but it is in fact a GRB. The angle from the Fermi LAT boresight at the GBM trigger time is 151 degrees. The GBM light curve consists of overlapping pulses with a duration (T90) of about 10.2 s (50-300 keV). The time-averaged spectrum from T0-0.9 s to T0+10.4 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.52 +/- 0.09 and the cutoff energy, parameterized as Epeak, is 410 +/- 150 keV. The event fluence (10-1000 keV) in this time interval is (9.4 +/- 0.54)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.8 s in the 10-1000 keV band is 11.2 +/- 0.96 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/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28341 SUBJECT: GRB 200901A: Swift-XRT refined Analysis DATE: 20/09/01 18:09:03 GMT FROM: Boris Sbarufatti at PSU J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU) and K. K. Simpson (PSU) report on behalf of the Swift-XRT team: We have analysed 2.5 ks of XRT data for GRB 200901A (Simpson et al. GCN Circ. 28335), from 3.1 ks to 11.1 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. Using 1707 s of PC mode data and 4 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 = 61.78319, -59.89084 which is equivalent to: RA (J2000): 04h 07m 07.97s Dec(J2000): -59d 53' 27.0" with an uncertainty of 1.8 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=0.95 (+0.28, -0.24). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.31 (+0.30, -0.28). The best-fitting absorption column is 2.2 (+0.9, -0.8) x 10^21 cm^-2, in excess of the Galactic value of 1.5 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.0 x 10^-11 (4.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.2 (+0.9, -0.8) x 10^21 cm^-2 Galactic foreground: 1.5 x 10^20 cm^-2 Excess significance: 4.2 sigma Photon index: 2.31 (+0.30, -0.28) If the light curve continues to decay with a power-law decay index of 0.95, the count rate at T+24 hours will be 7.9 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.3 x 10^-13 (3.8 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00994143. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28342 SUBJECT: GRB 200901A: Swift/UVOT Detection DATE: 20/09/01 20:16:07 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and K. K. Simpson (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 200901A 3053 s after the BAT trigger (Simpson et al., GCN Circ. 28335). A possible optical afterglow consistent with the XRT position (Kennea et al., GCN Circ. 28341) is detected in the initial UVOT exposures in the white filter only. It is not clear whether the source is fading. Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 3053 3202 147 20.6 +/- 0.3 white 3916 4115 197 20.5 +/- 0.2 v 4326 4526 197 >19.1 b 3711 3910 197 >20.4 u 3211 4987 290 >20.0 w1 4736 4936 197 >19.1 m2 4531 4731 197 >19.1 w2 4121 4321 197 >19.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28344 SUBJECT: GRB 200901A: Swift-BAT refined analysis DATE: 20/09/01 23:39:29 GMT FROM: Amy Lien at GSFC T. Sakamoto (AGU), S. D. Barthelmy (GSFC), 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), K. K. Simpson (PSU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (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 200901A (trigger #994143) (Simpson et al., GCN Circ. 28335). The BAT ground-calculated position is RA, Dec = 61.759, -59.901 deg which is RA(J2000) = 04h 07m 02.3s Dec(J2000) = -59d 54' 03.4" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 21%. The mask-weighted light curve shows several overlapping pulses that start at ~T-5 s and end at ~T+27 s. The main peak occurs at ~T0. The burst location went out of the BAT field of view at ~T+514 s. T90 (15-350 keV) is 20.37 +- 7.55 sec (estimated error including systematics). The time-averaged spectrum from T-4.43 to T+26.59 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.72 +- 0.11. The fluence in the 15-150 keV band is 2.9 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.01 sec in the 15-150 keV band is 7.7 +- 0.6 ph/cm2/sec. 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/994143/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28348 SUBJECT: GRB 200901A: MASTER OT early detection DATE: 20/09/02 12:59:10 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, A.Kuznetsov, K.Zhirkov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, A.Chasovnikov, A.Pozdnyakov, 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 (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-OAFA robotic telescope (Global MASTER-Net http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, v.2010, 30L) started in alert mode (Lipunov et al. GCN 28334) Swift GRB 200901A (Simpson et al. GCN 28335, Sakamoto et al. GCN 28344) errorbox observation 25s after notice time (46s after trigger time) at 2020-09-01 03:48:18 UT. There is OT at XRT (Kennea et al. GNC 28341) and UVOT (Breeveld et al. GCN 28342) position first 20 minutes after trigger time. Data analysis will continue. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28767 SUBJECT: GRB 200901A: FRAM-Auger optical limit DATE: 20/10/24 08:57:10 GMT FROM: Martin Jelinek at Astro.Inst-AVCR,Ondrejov Martin Jelinek, Jan Strobl (ASU CAS Ondrejov, CZ), Martin Masek, Petr Janecek, Sergey Karpov, Jakub Jurysek, Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza (Institute of Physics, Prague, CZ) report: The 30cm robotic telescope FRAM-Auger in Malargue (Argentina) reacted robotically to the Swift/BAT alert of GRB200901A (Simpson et al., GCNC 28335, Burrows et al., GCNC 28336, Kennea et al., GCNC 28341, and Breeveld et al., GCNC 28342). The weather was cloudy but as the clouds moved, we could select some good images, in particular there is a continuous set of 14 exposures between 4:00 and 4:17 UT, where the position could be well identified. We do not detect any new or strongly variable source at or around the reported X-ray errorbox at single frames or a combined 14 x 20s R-band image with the exposure mid-time 21.3 min after the initial trigger. The combined exposure has a limiting magnitude R(Vega) = 17.8, as calibrated against the Atlas Catalogue.