GRB 191027A
GCN Circular 26246
Subject
GRB 191027A: CALET Gamma-Ray Burst Monitor detection
Date
2019-11-14T01:02:06Z (6 years ago)
From
Valentin Pal'shin at AGU <val@phys.aoyama.ac.jp>
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.
GCN Circular 26100
Subject
Konus-Wind observation of GRB 191027A
Date
2019-10-30T20:03:53Z (6 years ago)
From
Anna Kozlova at Ioffe Institute <ann_kozlova@mail.ioffe.ru>
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.
GCN Circular 26096
Subject
Correction to GCN 26079 regarding GRB 191027A
Date
2019-10-30T02:41:15Z (6 years ago)
From
Jochen Greiner at MPI <jcg@mpe.mpg.de>
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.
GCN Circular 26087
Subject
IPN triangulation of GRB 191027A
Date
2019-10-29T07:12:56Z (6 years ago)
From
Anna Kozlova at Ioffe Institute <ann_kozlova@mail.ioffe.ru>
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.
GCN Circular 26079
Subject
GRB 191027A: BALROG localization (Fermi Trigger 593882352 / GRB 191027638)
Date
2019-10-27T16:38:02Z (6 years ago)
From
Jochen Greiner at MPE,Garching <jcg@mpe.mpg.de>
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
GCN Circular 26078
Subject
GRB 191027A: Fermi GBM Final Real-time Localization
Date
2019-10-27T15:29:32Z (6 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
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