//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26078 SUBJECT: GRB 191027A: Fermi GBM Final Real-time Localization DATE: 19/10/27 15:29:32 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 15:19:07 UT on 27 Oct 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191027A (trigger 593882352.589944 / 191027638). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 185.5, Dec = 30.4 (J2000 degrees, equivalent to J2000 12h 22m, 30d 23'), with a statistical uncertainty of 2.6 degrees. The angle from the Fermi LAT boresight is 33.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191027638/quicklook/glg_skymap_all_bn191027638.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191027638/quicklook/glg_healpix_all_bn191027638.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191027638/quicklook/glg_lc_medres34_bn191027638.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26079 SUBJECT: GRB 191027A: BALROG localization (Fermi Trigger 593882352 / GRB 191027638) DATE: 19/10/27 16:38:02 GMT FROM: Jochen Greiner at MPE,Garching B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 593882352 at 15:19:07 on 27 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) = 191.4+/-1.7 deg Decl.(2000.0) = -11.0+/-2.4 deg We estimate an additional systematic error of 1 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB191027638/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB191027638/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB191027638/json //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26087 SUBJECT: IPN triangulation of GRB 191027A DATE: 19/10/29 07:12:56 GMT FROM: Anna Kozlova at Ioffe Institute K. Hurley, on behalf of the IPN, I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report: The long-duration GRB 191027A (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 26078; BALROG localization: Biltzinger et al., GCN Circ. 26079) was detected by Fermi (GBM trigger 593882352), Konus-Wind, INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), and Swift (BAT), at about 55148 s UT (15:19:08). The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 186.657 (12h 26m 38s) +30.957 (+30d 57' 25") Corners: 166.009 (11h 04m 02s) +19.308 (+19d 18' 27") 202.558 (13h 30m 14s) +30.844 (+30d 50' 39") 206.169 (13h 44m 40s) +29.642 (+29d 38' 31") 170.349 (11h 21m 24s) +23.297 (+23d 17' 48") --------------------------------------------- The error box area is about 7.5 sq. deg, and its maximum dimension is 37.7 deg (the minimum one is 13.0 arcmin). The Sun distance was about 42 deg. This box may be improved. The IPN localization is consistent with, but reduces the area of, the Fermi-GBM one. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB191027_T55143/IPN The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26096 SUBJECT: Correction to GCN 26079 regarding GRB 191027A DATE: 19/10/30 02:41:15 GMT FROM: Jochen Greiner at MPI B. Biltzinger, J. Greiner (both MPE Garching) report: The BALROG localization of GRB 191027A (Fermi Trigger 593882352 / GRB 191027638) (https://grb.mpe.mpg.de/grb/GRB191027638/?data_version=0) published in Biltzinger et al. 2019 (GCN Circ. 26079) was sent by mistake, as it suffered an obvious problem in the automatic background fit (e.g. n1, n5). Corrected files have now been uploaded on https://grb.mpe.mpg.de/grb/GRB191027638/?data_version=zzz_bkg_corrected The history of the original fits will remain on the page. We apologize for any confusion this may have caused. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26100 SUBJECT: Konus-Wind observation of GRB 191027A DATE: 19/10/30 20:03:53 GMT FROM: Anna Kozlova at Ioffe Institute A.Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 191027A (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 26078; IPN triangulation: Hurley et al., GCN Circ. 26087) triggered Konus-Wind at T0=55143.905 s UT (15:19:03.905). The burst light curve shows a single pulse started at ~T0-0.1 s with a total duration of ~7.1 s. The emission is seen up to ~4 MeV. As observed by Konus-Wind, the burst had a fluence of 5.24(-1.01,+1.84)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0-0.002 s, of 7.53(-2.28,+2.60)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 4 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.28(-0.22,+0.26) and Ep = 443(-153,+468) keV (chi2 = 68/73 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.0 (chi2 = 68/72 dof). The spectrum near the maximum count rate (measured from T0 to T0+0.064 s) is best fit in the 20 keV - 4 MeV range by a power law with exponential cutoff model with alpha = -0.09(-0.61,+0.84) and Ep = 444(-106,+210) keV (chi2 = 8/15 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.2 (chi2 = 8/14 dof). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB191027_T55143/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26246 SUBJECT: GRB 191027A: CALET Gamma-Ray Burst Monitor detection DATE: 19/11/14 01:02:06 GMT FROM: Valentin Pal'shin at AGU T. Tamura (Kanagawa U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Torii (Waseda U), Y. Shimizu (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: GRB 191027A (Fermi GBM Final Real-time Localization: Fermi GBM Team, GCN Circ. 26078; BALROG localization: Biltzinger et al., GCN Circ. 26079, 26096; IPN triangulation: Hurley et al., GCN Circ. 26087; Konus-Wind observation: Ridnaia et al., GCN Circ. 26100; https://gcn.gsfc.nasa.gov/other/191027A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 15:19:06.826 UTC on 27 October 2019. The burst signal was seen by all CGBM detectors. The burst light curve shows a FRED-like pulse which starts at T+0.6 sec, peaks at T+0.9 sec and ends at T+3.0 sec. The T90 and T50 durations measured by the SGM data are 1.9 +- 0.6 sec and 0.6 +- 0.3 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1256224690/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.