GRB 191009A

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

At 07:08:56 UT on 9 Oct 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191009A (trigger 592297741.769374 / 191009298).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 26.8, Dec = 65.7 (J2000 degrees, equivalent to J2000 01h 47m, 65d 42'), with a statistical uncertainty of 1.4 degrees.

The angle from the Fermi LAT boresight is 40.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191009298/quicklook/glg_skymap_all_bn191009298.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/bn191009298/quicklook/glg_healpix_all_bn191009298.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191009298/quicklook/glg_lc_medres34_bn191009298.gif

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
592297741 at 07:08:56 on 09 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) = 30.0+/-5.9 deg
Decl.(2000.0) = 67.1+/-2.1 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB191009298/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB191009298/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB191009298/json

Q. B. Yi, S. Xiao, Q. Luo, C. Cai, C. K. Li,
X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, 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 2019-10-09T07:08:56.77 (T0), Insight-HXMT/HE detected 
GRB 191009A (trigger ID: HEB191009297) in a routine search of the data, 
which was also triggered by Fermi/GBM (GCN #25985
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 ). 

The Insight-HXMT/HE light curve mainly consists of a single  
pulse with a duration (T90) of 17.76 s measured from T0-1.56 s. 
The 1-ms peak rate, measured from T0+7.40 s, is 495 cnts/sec. 
The total counts from this burst is 1769 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB191009297_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.

R. Gaikwad, 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 191009A, which was also detected by Fermi GBM Final Real-time Localization (GCN #25985
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 ), BALROG localization (Biltzinger B. et al., GCN # 25986) and Insight-HXMT/HE (Luo Q. et al., GCN # 25997).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with the strongest peak at 2019-10-09 07:08:56.0 UT. The measured peak count rate associated with the burst is 572 cts/s above the background in the combined data of four quadrants, with a total of 1682 cts. The local mean background count rate was 473 cts/s. Using cumulative rates, we measure a T90 of 22.0 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.