GRB 200903E
GCN Circular 28397
Subject
Konus-Wind detection of GRB 200903E
Date
2020-09-08T21:25:50Z (6 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@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, very bright GRB 200903E
(AGILE detection: Ursi et al., GCN Circ. 28356;
AstroSat CZTI detection: Gupta et al., GCN Circ. 28367;
IPN triangulation: Hurley et al., GCN Circ. 28383)
triggered Konus-Wind at T0=9267.293 s UT (02:34:27.293).
The burst light curve shows a bright, multi-peaked structure
which started at ~T0-114.6 s and had a total duration of ~268.4 s.
The emission is seen up to ~6 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB200903_T09267/
As observed by Konus-Wind, the burst
had a fluence of 4.84(-0.24,+0.23)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+20.464 s,
of 5.12(-0.57,+0.57)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+98.816 s)
is best fit in the 20 keV - 6 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.23(-0.03,+0.03),
the high energy photon index beta = -2.30(-0.14,+0.10),
the peak energy Ep = 413(-30,+33) keV
(chi2 = 100/74 dof).
The spectrum near the maximum count rate
(measured from T0+17.152 to T0+22.272 s)
is best fit in the 20 keV - 6 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.04(-0.05,+0.06),
the high energy photon index beta = -2.37(-0.35,+0.20),
the peak energy Ep = 717(-95,+106) keV
(chi2 = 74/71 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 28383
Subject
IPN triangulation of GRB 200903E
Date
2020-09-07T18:57:54Z (6 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
K. Hurley, on behalf of the IPN,
I. G. Mitrofanov, D. V. Golovin, A. S. Kozyrev, 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. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
A. Ursi, F. Verrecchia, M. Tavani, N. Parmiggiani, C. Pittori,
A. Bulgarelli, on behalf of the AGILE 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 200903E
(AGILE detection: Ursi et al., GCN Circ. 28356;
AstroSat CZTI detection: Gupta et al., GCN Circ. 28367)
was detected by Konus-Wind, INTEGRAL (SPI-ACS),
Mars-Odyssey (HEND), AGILE (MCAL), and AstroSat (CZTI)
at about 9267 s UT (02:34:27).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
177.108 (11h 48m 26s) -31.594 (-31d 35' 40")
Corners:
178.077 (11h 52m 19s) -31.782 (-31d 46' 55")
177.058 (11h 48m 14s) -32.482 (-32d 28' 55")
176.149 (11h 44m 36s) -31.391 (-31d 23' 27")
177.164 (11h 48m 39s) -30.696 (-30d 41' 45")
---------------------------------------------
The error box area is 1.5 sq. deg, and its maximum
dimension is 1.8 deg (the minimum one is 1.1 deg).
The Sun distance was 41 deg.
This box may be improved.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB200903_T09267/IPN/
The localization of GRB 200903E is inconsistent with the localization
of GRB 200903B (GCN Circ. 28352).
The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
GCN Circular 28367
Subject
GRB 200903E: AstroSat CZTI detection
Date
2020-09-05T05:31:08Z (6 years ago)
From
Soumya Gupta at IUCAA/ASTROSAT <soumya@iucaa>
S. Gupta, V. Sharma, A. Vibhute and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (IUCAA/TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data showed the detection of a bright long GRB 200903E.
The source was clearly detected in the 40-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2020-09-03 02:34:50.40 UT. The measured peak count rate associated with the burst is 1061 +/- 38 cts/s above the background in the combined data of four quadrants, with a total of 22806 +/- 104 cts. The local mean background count rate was 597 +/- 1 cts/s. Using cumulative rates, we measure a T90 of 90.78 +/- 0.02 s. In preliminary analysis, we find that 1885 Compton events are associated with this event.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2020-09-03 02:34:49.00 UT. The measured peak count rate is 3999 +/- 75 cts/s above the background in the combined Veto data of four quadrants, with a total of 79278 +/- 173 cts. The local mean background count rate was 1611 +/- 1 cts/s. We measure a T90 of 90.50 +/- 0.03 s from the cumulative Veto light curve.
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.