[vsnet-grb-info 7121] IPN triangulation of bright GRB 081215A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8702
SUBJECT: IPN triangulation of bright GRB 081215A
DATE:    08/12/22 14:41:25 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val at mail.ioffe.ru>

S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, T. 
Cline, and K. Hurley on behalf of the Konus-Wind team,

M. Marisaldi, F. Fuschino, I. Donnarumma, E. Del Monte and M. Feroci on
behalf of the AGILE Team,

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

AGILE-MCAL and Konus-Wind observed the very bright GRB 081215A at about 
18:48:38 UT (corresponds to the Fermi/GBM
trigger 251059717 / 081215784: Preece, GCN 8678, 8679). The burst was 
outside the coded field of view of the SuperAGILE. The burst light curve 
shows a multipeaked structure with a total duration of ~10 sec.
The Swift-BAT saw nothing at this time. Hence, taking in account the 
high intensity of this GRB, that means the source of the burst was below 
the horizon for Swift.

Triangulation gives an annulus centered at RA(2000)=78.201 (05h 12m 48s)
  Dec(2000)=+17.575 (+17d 34' 32"), whose radius is 51.547 ± 0.508 deg
(3sigma). The Fermi/GBM ground position (Preece, GCN 8678) is 5 deg away 
from the center line of the annulus. The Konus ecliptic latitude 
response constrains the arrival direction to a band between ecliptic 
latitudes +30 and +53 degrees.

Combining all these data, we have triangulated
this burst to a single error box, whose corners are:
-----------------------------------------------------
     RA(2000), deg              Dec(2000), deg
-----------------------------------------------------
1: 129.016 (08h 36m 04s)   +50.756 (+50d 45' 22")
2: 122.577 (08h 10m 18s)   +58.308 (+58d 18' 28")
3: 121.670 (08h 06m 41s)   +57.174 (+57d 10' 27")
4: 127.051 (08h 28m 12s)   +51.125 (+51d 07' 32")
-----------------------------------------------------

Preliminary analysis of the Konus-Wind data yields
a burst fluence of ~7x10^-5 erg/cm2 (in the 20 keV - 5 MeV range),
and an Epeak of the time-integrated spectrum of ~450 keV.

Detailed spectral parameters will be reported later.

The K-W light curve of this GRB and IPN triangulation map is
available at http://www.ioffe.ru/LEA/GRBs/GRB081215_T67721/