Gamma-ray Burst 220601A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #32163
  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,
  E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
  S. Xiao, S.-L. Xiong, X.-Q. Li, X.-Y. Wen, L.-M. Song, S.-J. Zheng, W.-X. Peng, and F. Zhang on behalf of the GECAM team,
  and
  W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report:
  The long-duration GRB 220601A was detected by Konus-Wind, INTEGRAL (SPI-ACS), GECAM-B, and Mars-Odyssey (HEND) at about 22766 s UT (06:19:26).
  We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:

    ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
     224.703 (14h 58m 49s) -47.978 (-47d 58' 41")
    Corners:
     221.059 (14h 44m 14s) -50.313 (-50d 18' 48")
     221.153 (14h 44m 37s) -50.501 (-50d 30' 02")
     227.990 (15h 11m 58s) -45.375 (-45d 22' 31")
     227.888 (15h 11m 33s) -45.177 (-45d 10' 37")
    ---------------------------------------------
  

  The error box area is 1.2 sq. deg, and its maximum dimension is 7.0 deg (the minimum one is 11 arcmin). The Sun distance was 144 deg.
  This box may be improved.
  A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB220601_T22766/IPN/
  The time history and spectrum will be given in forthcoming GCN Circulars.
• GCN Circular #32172
  A. Lysenko, D. Frederiks, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report:
  The long-duration GRB 220601A (IPN triangulation: Kozyrev et al., GCN Circ. 32163) triggered Konus-Wind at T0=22766.297 s UT (06:19:26.297).
  The burst light curve shows a multipeaked structure which starts at ~T0-42.5 s and has a total duration of ~82.5 s. The emission is seen up to ~3 MeV.
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB220601_T22766/
  As observed by Konus-Wind, the burst had a fluence of 2.64(-0.16,+0.17)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+3.056s, of 6.19(-1.55,+1.57)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-averaged spectrum of the burst (measured from T0 to T0+41.216 s) is best fit in the 28 keV - 5 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.79(-0.17,+0.18) and Ep = 195(-17,+21) keV (chi2 = 58/71 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.6 (chi2 = 57/70 dof).
  The spectrum near the maximum count rate (measured from T0+0.256 to T0+8.448 s) is best fit in the 20 keV - 5 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.74(-0.16,+0.17), the high energy photon index beta = -2.81(-2.84,+0.34), the peak energy Ep = 220(-24,+31) keV (chi2 = 62/70 dof).
  All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.