Gamma-ray Burst 200422A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #27626
  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
  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
  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
  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
  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