//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26072 SUBJECT: Swift Trigger 931384: possible GRB 191025A DATE: 19/10/25 03:23:10 GMT FROM: Kim Page at U.of Leicester A. P. Beardmore (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU), K. L. Page (U Leicester), B. Sbarufatti (PSU), M. H. Siegel (PSU) and A. Tohuvavohu (Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 02:46:47 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 191025A (trigger=931384). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 320.755, -48.330 which is RA(J2000) = 21h 23m 01s Dec(J2000) = -48d 19' 46" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The significance is relatively low in both the rate and image domains. The XRT began observing the field at 02:48:08.9 UT, 82.0 seconds after the BAT trigger. No source was detected in 1.5 ks of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 85 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. Due to the low significance of the BAT trigger and the lack of immediate counterpart detection in the XRT or UVOT, the Swift team will not be able to confirm or deny whether this event is a GRB without further data. 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: 26073 SUBJECT: Possible GRB 191025A: FRAM-Auger optical limit DATE: 19/10/25 17:14:29 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 GRB191025A (Page et al., GCNC 26072), starting with a series of 20s unfiltered images at 02:47:17 UT, i.e. 30s post trigger. We do not detect any new or strongly variable source at or around the reported gamma-ray errorbox at single frames or combined 10 x 20s exposures taken between 30s and 585s after the initial trigger. The combined images have a limiting magnitude r'(AB) = 19.1, as calibrated against the APASS Catalogue. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26080 SUBJECT: Swift/BAT Trigger 931384 is not a GRB ( 191025A ) DATE: 19/10/27 21:40:55 GMT FROM: David Palmer at LANL Swift/BAT Trigger 931384 is not a GRB ( 191025A ) D. M. Palmer (LANL) reports on behalf of the Neil Gehrels Swift Observatory Team: After analysis of the complete data set, we have determined that Swift/BAT Trigger #931384 (tentatively labelled GRB 191025A in GCN #26072) is a statistical fluctuation (noise peak) in the image plane and not an astrophysical source.