GRB 200422A
GCN Circular 27626
Subject
IPN triangulation of GRB 200422A (long/very bright)
Date
2020-04-22T21:02:48Z (5 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@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,
S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT 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, very bright GRB 200422A
has been detected by Konus-Wind, INTEGRAL (SPI-ACS), Mars-Odyssey
(HEND), and Swift (BAT), so far, at about 26536 s UT (07:22:16).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
196.399 (13h 05m 36s) -20.245 (-20d 14' 41")
Corners:
195.143 (13h 00m 34s) -22.037 (-22d 02' 12")
195.441 (13h 01m 46s) -22.030 (-22d 01' 48")
197.651 (13h 10m 36s) -18.334 (-18d 20' 02")
197.341 (13h 09m 22s) -18.387 (-18d 23' 14")
---------------------------------------------
The error box area is 3548 sq. arcmin, and its maximum
dimension is 4.4 deg (the minimum one is 14 arcmin).
The Sun distance was about 162 deg.
This box may be improved.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB200422_T26537/IPN
The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
GCN Circular 27628
Subject
GRB 200422A: MASTER optical observations
Date
2020-04-22T22:52:54Z (5 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov (Lomonosov MSU), D.Svinkin (Ioffe Institute), E. Gorbovskoy,
V.Kornilov, P.Balanutsa,A.Kuznetsov,F.Balakin,V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva,
D.Kuvshinov, V.Shumkov, N.Tiurina (Lomonosov Moscow State University, SAI, Physics Department),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA),
H. Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API),
V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University)
MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru,
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)
located in South Africa (South African Astronomical Observatory)
started inspect of long bright IPN GRB200422A (Hurley et al., GCN 27626, Ttrig=3030-04-22 07:22:16)
at 2020-04-22 19:45:16UT with mlim~20.5.
The observations began at zenith distance = 59 deg. The sun altitude was -45 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/ligo_1.php?id=11505
GCN Circular 27630
Subject
GRB 200422A: AstroSat CZTI detection
Date
2020-04-23T09:23:31Z (5 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 (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data showed the detection of a long GRB 200422A, which was also detected by IPN (Hurley K. et al., GCN #27626) and Global MASTER-Net (Lipunov V. et al., GCN #27628).
The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with the strongest peak at 2020-04-22 07:22:15.088 UT. The measured peak count rate associated with the burst is 2864 +/- 56 cts/s above the background in the combined data of four quadrants, with a total of 29362 +/- 55 cts. The local mean background count rate was 566 +/- 2 cts/s. Using cumulative rates, we measure a T90 of 20.46 +/- 0.007 s. In preliminary analysis, we find that 2853 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.
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.
GCN Circular 27635
Subject
Konus-Wind observation of GRB 200422A
Date
2020-04-24T13:49:14Z (5 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration, very bright GRB 200422A
(IPN triangulation: Hurley et al., GCN Circ. 27626;
AstroSat-CZTI detection: Gupta et al., GCN Circ. 27630)
triggered Konus-Wind at T0=26537.847 s UT (07:22:17.847).
The burst light curve shows a multipeaked structure
which starts at ~T0-8.3 s and has a total duration of ~40 s.
The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB200422_T26537/
As observed by Konus-Wind, the burst
had a fluence of 5.12(-0.15,+0.15)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+3.728 s,
of 1.42(-0.12,+0.12)x10^-4 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+38.656 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.67(-0.05,+0.05),
the high energy photon index beta = -1.94(-0.04,+0.04),
the peak energy Ep = 552(-38,+42) keV
(chi2 = 105/97 dof).
The spectrum near the maximum count rate
(measured from T0+3.584 to T0+4.096 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.63(-0.11,+0.12),
the high energy photon index beta = -1.89(-0.09,+0.07),
the peak energy Ep = 762(-138,+174) keV
(chi2 = 89/79 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 27694
Subject
GRB 200422A: INTEGRAL observations
Date
2020-05-06T17:09:03Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
P. Minaev (IKI), I. Chelovekov (IKI), A. Pozanenko (IKI), S. Grebenev
(IKI) report on behalf of GRB IKI FuN:
We analyzed publically available data of SPI-ACS detector onboard the
INTEGRAL observatory. GRB 200422A (Hurley et al., GCN 27626; Gupta et
al., GCN 27630; Svinkin et al., GCN 27635) did not trigger IBAS
(http://ibas.iasf-milano.inaf.it/).
The GRB 200422A is detected in SPI-ACS data as very intense burst at
(UTC) 2020-04-22T07:22:03.1. The T_90 duration of the burst is 12.3 +/-
0.1 s in SPI-ACS. The fluence in 10-1000 keV energy band is 3.62e-4
erg/cm2 with statistical error of 5e-6 erg/cm2 (1.0e-4 ��� 1.2e-3 ergs/cm2
in the 95% confident region, including systematics) as defined after
calibration based on long duration GRBs (Chelovekov et al., in
preparation). We do not detect significant precursor in any 0.1 ��� 5 sec
time scale within 500 s prior to the trigger. Probable extended emission
is detected up to 250 s after the trigger.
The light curve can be found at
http://grb.rssi.ru/GRB200422A/GRB200422A_SPI-ACS_LC.png
We also put the spectral data of GRB 200422A reported by Konus-Wind
(Svinkin et al., GCN 27635) onto E_iso -- E_p diagram (AKA Amati
relation, see also Minaev et al., MNRAS, 492, 1919 (2020).
A GRB 200422A trajectory of parameters E_iso,i -- E_p,i along redshift
restricts the redshift of GRB 200422A as 2 > z > 0.1, see figure at
http://grb.rssi.ru/GRB200422A/GRB200422A_Ep-Eiso_diagram.png