GRB 220522B

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 220522B
was detected by Konus-Wind, INTEGRAL (SPI-ACS),
and Mars-Odyssey (HEND) at about 1058 s UT (00:17:38).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    43.717 (02h 54m 52s)  -3.789 ( -3d 47' 19")
  Corners:
    43.363 (02h 53m 27s)  -9.058 ( -9d 03' 28")
    43.540 (02h 54m 10s)  -9.308 ( -9d 18' 30")
    43.256 (02h 53m 01s)  +4.344 ( +4d 20' 39")
    42.925 (02h 51m 42s)  +5.219 ( +5d 13' 08")
  ---------------------------------------------
The error box area is 2.77 sq. deg, and its maximum
dimension is 14.54 deg (the minimum one is 11.88 arcmin).
The Sun distance was 22 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220522_T01058/IPN/

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.

A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long-duration GRB 220522B
(IPN triangulation: Kozyrev at al., GCN Circ. 32108
Loading...
 
 )
triggered Konus-Wind at T0=1058.258 s UT (00:17:38.258).

The burst light curve shows a multipeaked structure
which starts at ~T0-4.4 s and has a total duration of ~106.3 s.
The emission is seen up to ~4 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220522_T01058/

As observed by Konus-Wind, the burst
had a fluence of 5.49(-1.66,+1.13)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+9.344 s,
of 5.76(-2.35,+2.67)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 20 keV - 4 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.47(-0.53,+0.56),
the high energy photon index beta = -1.94(-0.86,+0.15),
the peak energy Ep = 230(-60,+197) keV
(chi2 = 85/67 dof).

The spectrum near the maximum count rate
(measured from T0+8.448 to T0+16.640 s)
is best fit in the 20 keV - 4 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.37(-0.48,+0.94),
the high energy photon index beta = -2.18(-0.90,+0.28),
the peak energy Ep = 224(-72,+108) keV
(chi2 = 73/66 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.