[vsnet-grb-info 13964] IPN Observations of GRB 130925A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15278
SUBJECT: IPN Observations of GRB 130925A
DATE:    13/09/30 22:05:33 GMT
FROM:    Kevin Hurley at UCBerkeley/SSL  <khurley at ssl.berkeley.edu>

K. Hurley, on behalf of the IPN team, 

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

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on
behalf of the GRS-Odyssey GRB team,

D. M. Smith, J. McTiernan, R. Schwartz, W.
Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, 

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

K. Yamaoka, M. Ohno, Y. Hanabata, Y. Fukazawa, T. Takahashi, M. Tashiro,
Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM team,

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

J. Goldsten, on behalf of the MESSENGER NS GRB team, and 

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

Eight IPN spacecraft observed GRB 130925A (Lien et al. GCN 15246,
Markwardt et al. 15247).  When the responses of all the spacecraft are
considered, the IPN had an uninterrupted view of this event from
roughly 900 s before the Swift BAT trigger, to ~7100 s after it.
Constraints on the arrival directions of the four main emission
episodes strengthen the case for their common origin, as suggested by
Savchenko et al. (GCN 15259).  The following table details the
observations.  The times are relative to the BAT trigger at 15084 s UT
(04:11:24).  N/O means the episode was not observable.

 ----------------------------------------------------------------------------
 Instrument/ |    Precursor |   1st         |   2nd          |    3rd
 spacecraft  |      -900 s  | episode       | episode        |  episode*
             |              | -130 -> +170 s|+1750 -> +2950 s|+3730 -> +4360 s
 ----------------------------------------------------------------------------
 Swift BAT          No           Trig            N/O              No
 Fermi GBM          Trig         Trig            N/O              No
 INTEGRAL SPI-ACS   No           Yes             Yes              Yes
 Konus Wind         Yes          Yes             Yes              Yes
 MESSENGER          No           Yes             Yes              No
 Mars Odyssey       No           N/O             Yes              No
 Suzaku WAM         No           No              Yes              No
 RHESSI             Yes          Yes             N/O              No
------------------------------------------------------------------------------
*also observed and localized by MAXI (Suzuki et al. GCN 15248)

We conclude from these observations that the total duration of this
event in >25 keV gamma-rays above the IPN flux/fluence threshold was 
at least 5260 s, and ~7150 s long when the later episodes, observed only
by BAT (GCN 15257), are included.