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GRB 221022C

GCN Circular 32857

Subject

IPN triangulation of GRB 221022C (short)

Date

2022-10-26T17:33:29Z (3 years ago)

From

Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team, report:

The short-duration GRB 221022C
(Fermi-GBM detection: Poolakkil and Meegan, GCN Circ. 32836Loading...
 
 )
was detected by Fermi (GBM trigger 688142511), INTEGRAL (SPI-ACS),
Konus-Wind, and Swift (BAT) at about 52906 s UT (14:41:46).
The burst was outside the coded field of view of the BAT.

We have triangulated it to two preliminary, 3 sigma error boxes
whose coordinates are:

Box 1:
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   231.382 (15h 25m 32s) -57.938 (-57d 56' 16")
  Corners:
   234.870 (15h 39m 29s) -56.438 (-56d 26' 17")
   235.716 (15h 42m 52s) -56.321 (-56d 19' 17")
   226.200 (15h 04m 48s) -59.592 (-59d 35' 33")
   224.388 (14h 57m 33s) -59.790 (-59d 47' 25")
  ---------------------------------------------

Box 2:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   193.697 (12h 54m 47s) -60.774 (-60d 46' 28")
  Corners:
   189.204 (12h 36m 49s) -59.842 (-59d 50' 33")
   188.243 (12h 32m 58s) -59.852 (-59d 51' 09")
   200.024 (13h 20m 06s) -61.584 (-61d 35' 03")
   201.980 (13h 27m 55s) -61.500 (-61d 29' 58")
  ---------------------------------------------
The error box area is 1.28 sq. deg, and their maximum
dimension is 6.91 deg (the minimum one is 12.4 arcmin).
The Sun distance was 50 deg.

This localization may be improved.

The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM final localization (glg_healpix_all_bn221022612_v00).

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB221022_T52903/IPN

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

GCN Circular 32901

Subject

Konus-Wind detection of GRB 221022C

Date

2022-10-31T14:54:50Z (3 years ago)

From

Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>

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

The short-duration GRB 221022C
(IPN triangulation: Svinkin et al., GCN Circ. 32857Loading...
 
 )
triggered Konus-Wind at T0=52903.608 s UT (14:41:43.608).

The burst light curve shows a multipeaked structure,
which starts at T0-88 ms and has a total duration of ~128 ms.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB221022_T52903/

As observed by Konus-Wind, the burst
had a fluence of 8.55(-1.23,+1.68)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.012 s,
of 2.01(-0.39,+0.47)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the main fraction of the burst emission was detected
before the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modelling the KW 3-channel time-integrated spectrum
(measured from T0-0.088 s to T0+0.040 s)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = -0.09(-0.28,+0.40) and Ep = 548(-86,+121) keV.

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.