GRB 190326B

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:

"At 07:31:39.00 UT on 26 March 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190326B (trigger 575278303 / 190326314).

The on-ground calculated location, using the GBM trigger data, 
is RA = 264.2, DEC = 68.3 (J2000 degrees, equivalent
to 17h 37m, 68d 18'), with an uncertainty of 1.3 degrees 
(radius, 1-sigma containment, statistical only; there is additionally a 
systematic error which we have characterized as a core-plus-tail model, 
with 90% of GRBs having a 3.7 deg error and a small tail suffering a 
larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight at the GBM trigger time is 21 degrees.

The GBM light curve consists of multiple pulses with a duration (T90)
of about 56 s (50-300 keV). The time-averaged spectrum from 
T0-2.048 s to T0+59.393 s is best fit by a Band function with Epeak = 163 +/- 14 keV,
alpha = -0.33 +/- 0.10, and beta = -1.93 +/- 0.07

The event fluence (10-1000 keV) in this time interval is
(1.78 +/- 0.05)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+56.5128 s in the 10-1000 keV band
is 7.8 +/- 0.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."

Q. Luo, 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 2019-03-26T07:31:47.000 (T0), the Insight-HXMT/HE detected
GRB 190326B(trigger ID: HEB190326313) in a routine search of the data,
which was also triggered by Fermi/GBM(A. von Kienlin et al. ,GCN 24013).

The Insight-HXMT/HE light curve mainly consists of multiple
pulses with a duration (T90) of 58.45 s measured from T0+0.47 s.
The 1-ms peak rate, measured from T0+48.526 s, is 3079 cnts/sec.
The total counts from this burst is 28802 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190326313_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 (record 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
fundedjointly 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.

V. Sharma, D. Bhattacharya, A. Vibhute and T. Khanam (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 long bright GRB 190326B, which was also detected by Fermi-GBM (Kienlin A. von et al., GCN # 24013) and Insight-HXMT/HE detection (Luo Q. et al., GCN # 24019).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with strongest peak at 07:32:36.5 UT. The measured peak count rate associated with the burst is 418 cts/s above the background in the combined data of four quadrants, with a total of 4932 cts. The local mean background count rate was 630 cts/s. Using cumulative rates, we measure a T90 of  54.3 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.