//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25893 SUBJECT: GRB 191001A: Fermi GBM Final Real-time Localization DATE: 19/10/01 06:50:20 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 06:41:50 UT on 1 Oct 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191001A (trigger 591604915.579128 / 191001279). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 308.9, Dec = 18.5 (J2000 degrees, equivalent to J2000 20h 35m, 18d 30'), with a statistical uncertainty of 3.3 degrees. The angle from the Fermi LAT boresight is 102.0 degrees. The skymap can be found here: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191001279/quicklook/glg_skymap_all_bn191001279.png The HEALPix FITS file, including the estimated localization systematic, can be found here: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191001279/quicklook/glg_healpix_all_bn191001279.fit The GBM light curve can be found here: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191001279/quicklook/glg_lc_medres34_bn191001279.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25894 SUBJECT: GRB 191001A: BALROG localization (Fermi Trigger 591604915 / GRB 191001279) DATE: 19/10/01 07:00:08 GMT FROM: Jochen Greiner at MPE,Garching J. Burgess , F. Kunzweiler, B. Biltzinger, F. Berlato, & J. Greiner (all MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 591604915 at 06:41:50 on 01 Oct. 2019 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position (1 sigma statistical errors) is: RA(2000.0) = 313.4+/-6.0 deg Decl.(2000.0) = 15.1+/-1.4 deg We estimate an additional systematic error of 2 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB191001279/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB191001279/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB191001279/json //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25911 SUBJECT: GRB 191001A: DDOTI Optical Counterpart Candidate DATE: 19/10/01 22:28:50 GMT FROM: Emma Margarita Pereyra Talamantes at IA-UNAM Ensenada Margarita Pereyra (UNAM), Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Diego Gonzalez (UNAM), Alexander Kutyrev (GSFC/UMD), illiam H. Lee (UNAM), Eleonora Troja (GSFC/UMD), Gabriele Minervini (INAF/IAPS-Rome) and Tanner Wolfram (ASU), Simone Dichiara (GSFC/UMD) report: We observed the field of GRB 191001A (trigger 591604915, Fermi GBM Team, GCN Circ. 25893) from 2019 Oct 1 06:48:21 UTC (391 seconds after the trigger) to 06:59:52 UTC with the DDOTI wide-field imager at the Observatorio Astronomico Nacional on Sierra San Pedro Martir ( http://ddoti.astroscu.unam.mx/). We calibrated our images against the APASS catalog and obtained a 10-sigma limiting magnitude of w = 18.6. Comparing our 10-sigma detections against the USNO-B1 and Pan-STARRS DR1 catalogues, we detect an uncatalogued source at 20:20:47.65 +15:05:03.4 that fades at the 2.4 sigma level from w = 16.7 to 17.0. Specifically, it fades as a power-law in time since trigger with an index of -0.53 +/- 0.23. Independently and roughly simultaneously, the source was detected at a similar magnitude by ATLAS as ATLAS19wxr and is cataloged in the Transient Name Server as AT2019rog (TNS Astronomical Transient Report 48331). The discovery report states that it was not detected on 2019 Sep 29. No known minor planets, brighter than V = 24.0, were found in the 5 arcmin region around the source position at the time our observations were performed. The source is about 1 sigma from the Fermi Final Real-Time Localization and BALROG positions (Fermi GBM Team, GCN Circ. 25893; Burgess et al., GCN Circ. 25894). We suggest that it might be the optical counterpart of the GRB and encourage further observations. We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25918 SUBJECT: GRB 191001A: RATIR Optical and NIR Observations DATE: 19/10/02 04:57:45 GMT FROM: Emma Margarita Pereyra Talamantes at IA-UNAM Ensenada Margarita Pereyra (UNAM), Alan M. Watson (UNAM), Eleonora Troja (GSFC), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Diego Gonzalez (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of the candidate afterglow of GRB 191001A (trigger 591604915, Fermi GBM Team, GCN Circ. 25893, Pereyra et al. GCN Circ. 25911), centered at 20:20:47.65 +15:05:03.4, with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2019/10 2.12 to 2019/10 2.17 UTC (20.08 to 21.45 hours after the Fermi trigger), obtaining a total of 0.34 hours exposure in the g and r bands, 0.67 hours exposure in the i band and 0.37 hours exposure in the i, Z, Y, J, and H bands. At the position of the transient source AT2019rog discovered independently by ATLAS and DDOTI, in comparison with the USNO-B1, PS1 and 2MASS catalogs, we obtain the following upper limits (3-sigma): g > 23.20 r > 23.01 i > 23.26 Z > 21.40 Y > 21.49 J > 21.22 H > 20.92 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The non-detection implies that the source has faded by about 6 magnitudes in 20 hours. This is consistent with it being the afterglow of GRB 191001A. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25919 SUBJECT: GRB 191001A: KAIT Optical Upper Limit DATE: 19/10/02 05:54:41 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to the GBM GRB 191001A (Fermi GBM team, GCN 25893) starting at ~21.8 hours after the burst. We observed the afterglow candidate AT2019rog, which was discovered independently by ATLAS (Tonry et al., TNSTR 1954) and DDOTI (Pereyra et al., GCN 25911), obtaining 17 x 60s images in the clear (roughly R) filters. We do not detect the afterglow candidate in our co-add images with limiting mag of ~21.5. Our non-detection result is consistent with observations from RATIR (Pereyra et al., GCN 25918). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25924 SUBJECT: GRB 191001A: Swift ToO observations DATE: 19/10/02 14:08:17 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 Fermi/GBM GRB 191001A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00020949 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 Fermi/GBM 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: 25926 SUBJECT: IPN triangulation of GRB 191001A DATE: 19/10/02 18:21:00 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, K. Hurley, on behalf of the IPN, and A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team, report: The long duration GRB 191001A (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 25893; BALROG localization: Burgess et al., GCN Circ. 25894) was detected by Fermi (GBM trigger 591604915), Konus-Wind, and Swift (BAT) at about 24110 s UT (06:41:50). The burst was outside the coded field of view of the BAT. We have triangulated this GRB to a Konus-GBM annulus centered at RA(2000)=346.113 deg (23h 04m 27s) Dec(2000)=-7.939 deg (-7d 56' 21"), whose radius is 46.475 +/- 2.251 deg (3 sigma). The distance between the optical transient ATLAS19wxr (Smartt, et al., GCN Circ. 25922; Pereyra et al., GCN Circ. 25911) and the annulus center line is 9.3 arcmin, supporting the association of the transient and the GRB. This annulus may be improved. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB191001_T24130/IPN //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25938 SUBJECT: GRB 191001A: Fermi GBM observation DATE: 19/10/03 17:42:48 GMT FROM: Rachel Hamburg at UAH E. Bissaldi (Politecnico & INFN Bari), R. Hamburg (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 06:41:50.58 UT on 1 October 2019, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 191001A (trigger 591604915 / 191001279). The on-ground calculated location has been reported in GCN #25893, and an IPN annulus consistent with the GBM localization was reported in GCN #25926. The ATLAS and DDOTI (GCN #25911) optical counterpart position are consistent with the GBM localization. The GBM light curve consists of several pulses with a duration (T90) of about 24 s (50-300 keV). The time-averaged spectrum from T0-4.99 s to T0+25.73 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.8 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 114 +/- 9 keV. The event fluence (10-1000 keV) in this time interval is (4.7 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+15.7 s in the 10-1000 keV band is 10.5 +/- 0.4 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: 25942 SUBJECT: GRB 191001A: Swift-XRT observations DATE: 19/10/03 20:26:43 GMT FROM: Antonino D'Ai at IASF-PA D.N. Burrows (PSU), J. D. Gropp (PSU), A. Tohuvavohu (U. Toronto), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/GBM detected burst GRB 191001A (GCN Circ. 25893, 25894), collecting 5.2 ks of Photon Counting (PC) mode data between T0+114.2 ks and T0+161.3 ks. No X-ray sources have been detected consistent with being within 2.0 arcsec of the likely associated optical transient AT2019rog (GCN Circ. 25911, 25918, 25919 and Tonry et al., TNSTR 1954). The 3-sigma upper limit in the field ranges from ~0.002 to ~0.003 ct s^-1, corresponding to a 0.3-10 keV observed flux of 8.6e-14 to 1.0e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum). The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00020949. This circular is an official product of the Swift-XRT team.