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TITLE:   GCN CIRCULAR
NUMBER:  32117
SUBJECT: IPN triangulation of GRB 220524B
DATE:    22/05/25 21:42:09 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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,

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 220524B
was detected by Konus-Wind, INTEGRAL (SPI-ACS),
and Mars-Odyssey (HEND) at about 57898 s UT (16:04:58).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    70.274 (04h 41m 06s) -19.486 (-19d 29' 11")
  Corners:
    70.075 (04h 40m 18s) -21.168 (-21d 10' 04")
    70.146 (04h 40m 35s) -21.193 (-21d 11' 34")
    70.452 (04h 41m 49s) -17.794 (-17d 47' 37")
    70.382 (04h 41m 32s) -17.767 (-17d 46' 01")
  ---------------------------------------------
The error box area is 840 sq. arcmin, and its maximum
dimension is 3.43 deg (the minimum one is 4.1 arcmin).
The Sun distance was 40 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220524_T57898/IPN

The time history and spectrum will be given in forthcoming GCN Circulars.

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TITLE:   GCN CIRCULAR
NUMBER:  32123
SUBJECT: Konus-Wind detection of GRB 220524B
DATE:    22/05/26 13:06:23 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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 220524B (IPN triangulation: Kozyrev et al., GCN 32117)
triggered Konus-Wind (KW) at T0=57898.077 s UT (16:04:58.077).

The burst light curve shows two multipeaked pulses
in the interval from ~T0-3 s to ~T0+20 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/GRB220524_T57898/

As observed by Konus-Wind, the burst had
a fluence of (1.6 ± 0.5)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 16.576 s,
of (7.4 ± 2.3)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+24.832 s)
is best fit in the 20 keV - 15 MeV range by
a Band function with the following model parameters:
the low-energy photon index alpha = -1.31 (-0.26,+0.44),
the high energy photon index beta = -1.96 (-0.76,+0.21),
the peak energy Ep = 249 (-130,+380) keV,
chi2 = 94/97 dof.

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.