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GRB 160822A

GCN Circular 19852

Subject

IPN Triangulation of GRB 160822A (short/hard)

Date

2016-08-24T00:18:54Z (9 years ago)

From

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

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa,
and A. Goldstein, on behalf of the Fermi GBM team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

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

The short-duration, hard-spectrum, bright GRB 160822A has been detected 
by Fermi (GBM; Hamburg et al., GCN Circ. 19845Loading...
 
 ), Konus-Wind, INTEGRAL 
(SPI-ACS), and Swift (BAT) at about 58060 s UT (16:07:40). 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:
    272.129 (18h 08m 31s)  +3.584 ( +3d 35' 01")
   Corners:
    272.065 (18h 08m 16s)  +1.771 ( +1d 46' 15")
    271.809 (18h 07m 14s)  +1.779 ( +1d 46' 45")
    272.205 (18h 08m 49s)  +5.396 ( +5d 23' 45")
    272.462 (18h 09m 51s)  +5.389 ( +5d 23' 19")
   ---------------------------------------------
The error box area is 3348 sq. arcmin, and its maximum
dimension is 3.67 deg (the minimum one is 15.4 arcmin).
The Sun distance was 118 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB160822_T58061/IPN/

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

GCN Circular 19853

Subject

Konus-Wind observation of GRB 160822A

Date

2016-08-24T11:37:30Z (9 years ago)

From

Anna Kozlova at Ioffe Institute <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration GRB 160822A
(Fermi GBM detection: Hamburg et al., GCN Circ. 19845Loading...
 
 ;
IPN triangulation: Svinkin et al., GCN Circ. 19852Loading...
 
 )
triggered Konus-Wind at T0=58061.153 s UT (16:07:41.153).

The burst light curve shows a single pulse
which starts at T0-0.016 s with a total duration of 0.03 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/GRB160822_T58061/

As observed by Konus-Wind, the burst
had a fluence of 7.60(-1.87,+5.46)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.006 s,
of 3.95(-1.40,+4.02)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The spectrum of the burst
(measured from T0 to T0+0.064 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.59 (-0.75,+1.34)
and Ep = 599 (-222,+2249) keV (chi2 = 11/14 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.9
(chi2 = 11/13 dof)

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