GRB 191202A

The Fermi GBM team reports the detection of a likely LONG GRB

At 20:48:51 UT on 2 Dec 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191202A (trigger 597012536.229574 / 191202867).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 245.3, Dec = 16.8 (J2000 degrees, equivalent to J2000 16h 21m, 16d 48'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 15.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191202867/quicklook/glg_skymap_all_bn191202867.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/bn191202867/quicklook/glg_healpix_all_bn191202867.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191202867/quicklook/glg_lc_medres34_bn191202867.gif

R. Gaikwad, S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a GRB 191202A, which was also detected by Fermi GBM Final Real-time Localization (GCN #26323
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 ).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 2019-12-02 20:48:51 UT. The measured peak count rate associated with the burst is 829 cts/s above the background in the combined data of four quadrants, with a total of 3809 cts. The local mean background count rate was 499 cts/s. Using cumulative rates, we measure a T90 of 11.92 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.

P. Veres and C. Meegan (both UAH)
report on behalf of the Fermi GBM Team:

"At 20:48:51.23 UT on 2 December 2019, the Fermi Gamma-Ray Burst Monitor
(GBM)
triggered and located GRB 191202A (trigger 597012536 / 191202867)
which was also detected by the Fermi-LAT.
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight at the GBM trigger time is 12
degrees.

The GBM light curve shows two pulses
with a duration (T90) of about 30.7 s (50-300 keV).
The time-averaged spectrum from T0-1.0 s to T0+18.4 s is
best fit by a Band function with Epeak = 190 +/- 19 keV,
alpha = -1.20 +/- 0.04, and beta = -2.05 +/- 0.08.

The event fluence (10-1000 keV) in this time interval is
(1.95 +/- 0.04)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+9.0 s in the 10-1000 keV band
is 23.5 +/- 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/"

D. Kocevski (NASA/GSFC), R. Angioni (ASI/SSDC and INFN, Roma2), F. Longo (University and INFN, Trieste),

N. Omodei (Stanford University), E. Bissaldi (Politecnico and INFN, Bari) and L. Scotton (CNRS/IN2P3/LUPM, Montpellier)

report on behalf of the Fermi-LAT Collaboration:


On December 2nd, 2019, Fermi-LAT detected high-energy emission from

GRB 191202A, which was also detected by Fermi-GBM (trigger 597012536/191202867) (Veres et al. 2019, GCN 26329
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 ).


The best LAT on-ground location is found to be


RA, Dec = 249.54, 17.56 (degrees, J2000)


with an error radius of 0.24 deg (90% containment, statistical error only).

This was 11.4 deg from the LAT boresight at the time of the GBM trigger:


T0 = 20:48:51.23 UT.


The data from the Fermi-LAT show a significant increase
in the event rate after the GBM trigger that is spatially correlated with the
GBM emission with high significance.
The photon flux above 100 MeV in the time interval 0-1000s after the
GBM trigger is 2.6e-06 +/- 8.8e-07 ph/cm2/s.



The estimated photon index above 100 MeV is -1.6 +/- 0.2.




The highest-energy photon is a 1.8 GeV event which is observed 393 seconds

after the GBM trigger.


The Fermi-LAT point of contact for this burst is

Lorenzo Scotton (lorenzo.scotton@lupm.in2p3.fr).



The Fermi-LAT is a pair conversion telescope designed to cover

the energy band from 20 MeV to greater than 300 GeV.

It is the product of an international collaboration between

NASA and DOE in the U.S. and many scientific institutions

across France, Italy, Japan and Sweden.

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Lysenko, A. Ridnaia and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB191202A (AstroSat CZTI detection: Gaikwad et al., 
GCN 26326
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 ;
Fermi GBM observation: Veres & Meegan, GCN 26329
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 ;
Fermi-LAT detection: Kocevski et al., GCN 26330
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 )
triggered Konus-Wind at T0=74930.521 s UT (20:48:50.521).

The burst light curve shows a multi-peaked structure
which starts at ~T0-3.9 s and has a total duration of~17.6 s.
The emission is seen up to ~1.3 MeV.

As observed by Konus-Wind, the burst
had a fluence of 2.78(-0.68,+0.76)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+7.024 s,
of 8.80(-2.80,+3.04)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+15.872 s)
is best fit in the 20 keV - 1.3 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.22(-0.12,+0.22),
the high energy photon index beta = -2.17(-1.00,+0.26),
the peak energy Ep = 265(-87,+91) keV,
chi2 = 46/59 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB191202_T74930/

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.

Y. G. Zheng, C. Cai, Q. Luo, S. Xiao, Q. B. Yi, 
Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, 
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team:

At 2019-12-02T20:48:59.55 (T0), Insight-HXMT/HE detected 
GRB 191202A (trigger ID: HEB191202867) in a routine search of the data, 
which was also triggered by Fermi/GBM (GCN #26323
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 ), 
AstroSat CZTI (GCN #26326
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 ) and Konus-Wind (GCN #26344
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 ).

The Insight-HXMT/HE light curve mainly consists of a single  
pulse with a duration (T90) of 11.09 s measured from T0-5.67 s. 
The 1-ms peak rate, measured from T0-0.08 s, is 2101 cnts/sec. 
The total counts from this burst is 5960 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB191202867_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (deposited energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
funded jointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information about it could be found at: 
http://www.hxmt.org.