Gamma-ray Burst 220128A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #31536
  A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars-Odyssey team,
  D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko, 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, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, and
  W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on behalf of the GRS-Odyssey GRB team, report:
  The long-duration GRB 220128A was detected by Konus-Wind, Swift (BAT), INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND) at about 11897 s UT (03:18:17). The burst was outside the coded field of view of the BAT.
  We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:

    ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
     350.191 (23h 20m 46s) -49.734 (-49d 44' 02")
    Corners:
     349.616 (23h 18m 28s) -46.520 (-46d 31' 11")
     350.856 (23h 23m 25s) -52.699 (-52d 41' 57")
     350.687 (23h 22m 45s) -52.865 (-52d 51' 53")
     349.478 (23h 17m 55s) -46.702 (-46d 42' 08")
    ---------------------------------------------
  

  The error box area is 2688 sq. arcmin, and its maximum dimension is 6.38 deg (the minimum one is 7 arcmin). The Sun distance was 42 deg.
  This box may be improved.
  A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB220128_T11896/IPN/
  The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
  
• GCN Circular #31537
  D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
  The long GRB 220128A (IPN localization: Kozyrev et al., GCN 31536) triggered Konus-Wind (KW) at T0=11896.619 s UT (03:18:16.619).
  The burst light curve shows a multi-peaked structure, which starts at ~T0-10 s and has a total duration of ~47 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/GRB220128_T11896/
  As observed by Konus-Wind, the burst had a fluence of (3.2 ± 0.7)x10^-5 erg/cm^2 and a 64-ms peak energy flux, measured from T0 + 10.496 s, of (5.9 ± 1.1)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
  The time-averaged spectrum (measured from T0 to T0+24.832 s) is best fit in the 20 keV - 20 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.92 (-0.18,+0.28), the high energy photon index beta = -2.19 (-1.92,+0.32), the peak energy Ep = 406 (-135,+174) keV, chi2 = 88/97 dof.
  All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary.
• GCN Circular #31539
  V. Prasad (IUCAA), G. Waratkar (IITB), A. Suresh (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
  Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed detection of a long GRB 220128A, which was also detected by Konus-Wind (Frederiks et al. GCN 31537) with IPN localization (Kozyrev et al., GCN 31536).
  The source was 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 2022-01-28 03:18:22.65 UT. The measured peak count rate is 617 (+71, -81) cts/s above the background in the combined Veto data of four quadrants, with a total of 4281 (+424, -589) cts. The local mean background count rate was 1477 (+4, -4) cts/s. We measure a T90 of 26 (+4, -4) 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 [1]. 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.

  Links:
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  [1] http://astrosat.iucaa.in/czti/?q=grb