GRB 191031A
GCN Circular 26101
Subject
GRB 191031A: Swift detection of a burst
Date
2019-10-31T00:45:49Z (6 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
A. D'Ai (INAF-IASFPA), E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC),
J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),
D. M. Palmer (LANL), M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto)
report on behalf of the Neil Gehrels Swift Observatory Team:
At 00:36:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 191031A (trigger=932435). Swift did not slew due to an
observing constraint. The BAT on-board calculated location is
RA, Dec 233.470, +6.144 which is
RA(J2000) = 15h 33m 53s
Dec(J2000) = +06d 08' 37"
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 ~1500 counts/sec (15-350 keV), at ~2 sec after the trigger.
Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 23:18 UT on 2019 December 22. There will thus be no XRT
or UVOT data for this trigger before this time.
Burst Advocate for this burst is A. D'Ai (antonino.dai AT inaf.it).
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/)
GCN Circular 26102
Subject
GRB 191031A: Fermi GBM Final Real-time Localization
Date
2019-10-31T00:46:50Z (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 00:36:35 UT on 31 Oct 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191031A (trigger 594175000.608294 / 191031025).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 247.3, Dec = 22.1 (J2000 degrees, equivalent to J2000 16h 29m, 22d 06'), with a statistical uncertainty of 12.9 degrees.
The angle from the Fermi LAT boresight is 93.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031025/quicklook/glg_skymap_all_bn191031025.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/bn191031025/quicklook/glg_healpix_all_bn191031025.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031025/quicklook/glg_lc_medres34_bn191031025.gif
GCN Circular 26103
Subject
GRB 191031A: COATLI Optical Observations
Date
2019-10-31T03:43:46Z (6 years ago)
From
Alan M Watson at UNAM <alan@astro.unam.mx>
Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Diego Gonz��lez
(UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Margarita Pereyra
(UNAM), and Eleonora Troja (GSFC) report:
We observed the field of GRB 191031A (D'Ai et al., GCN Circ. 26101; Fermi GBM
Team, GCN Circ. 26102) with the COATLI 50-cm telescope and interim imager at the
Observatorio Astron��mico Nacional on the Sierra de San Pedro M��rtir
(http://coatli.astroscu.unam.mx) from 2019-10-31 02:14 UTC (1.63 hours after the
trigger) to 02:25, obtaining a total of 540 seconds of exposure in the w filter.
The observations were taken at airmasses between 6.4 and 8.3.
We do not detetect any uncataloged sources in the BAT error region to a 10-sigma
limit of w = 18.75.
Our w magnitudes are calibrated against the Pan-STARRS1 catalog, are on an
approximate AB system (Becerra et al., 2019, ApJ, 872, 118), and are not
corrected for Galactic extinction in the direction of the GRB.
We thank the COATLI technical team and the staff of the Observatorio Astron��mico
Nacional.
GCN Circular 26116
Subject
GRB 191031A: Fermi GBM detection
Date
2019-10-31T23:56:09Z (6 years ago)
From
Rachel Hamburg at UAH <rkh0007@uah.edu>
S. Lesage (UAH), R. Hamburg (UAH), and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 00:36:35.61 UT on 31 October 2019, the Fermi Gamma-Ray Burst Monitor
(GBM)
triggered and located GRB 191031A (trigger 594175000 / 191031025)
which was also detected by the Swift/BAT (D'Ai et al. 2019, GCN 26101)
The Fermi GBM Final Real-time Localization (GCN 26102) is consistent with
the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 106
degrees.
The GBM light curve shows two pulses with a duration (T90) of about 200 s
(50-300 keV). The time-averaged spectrum of the first pulse from T0-10.24 s
to T0+10.24 s is best fit by a power law with an exponential
high-energy cutoff. The power law index is -0.9 +/- 0.2 and the cutoff
energy, parameterized as Epeak, is 218 +/- 57 keV. The time-averaged
spectrum of the second pulse from T+174.08 to T0+197.64 is best fit
by the same function with an index of -1.1 +/- 0.1 and an Epeak of 242 +/-
48 keV.
The event fluence (10-1000 keV) in the time interval of the two pulses is
(6.6 +/- 0.6)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+175.56 s in the 10-1000 keV band
is 2.5 +/- 0.3 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/"
GCN Circular 26131
Subject
GRB 191031A: Swift-BAT refined analysis
Date
2019-11-01T19:05:44Z (6 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
A. D'Ai (INAF-IASFPA), H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-61 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 191031A (trigger #932435)
(D'Ai, et al., GCN Circ. 26101). The BAT ground-calculated position is
RA, Dec = 233.490, 6.109 deg which is
RA(J2000) = 15h 33m 57.7s
Dec(J2000) = +06d 06' 32.9"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 46%.
The mask-weighted light curve shows a single pulse with some overlying
structure. The emission starts at ~T-8 sec, peaks at T+3 sec, and decays
to background by ~T+18 sec. A pre-planned spacecraft slew took the burst
location out of the field of view by T+95 sec. T90 (15-350 keV) is 19.1 +- 6.3 sec
(estimated error including systematics).
The time-averaged spectrum from T-11.08 to T+16.87 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.38 +- 0.19. The fluence in the 15-150 keV band is 9.0 +- 1.1 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+3.48 sec in the 15-150 keV band
is 1.0 +- 0.2 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/932435/BA/