GRB 081017

O. Godet (U Leicester), S. D. Barthelmy (GSFC),
P. A. Evans (U Leicester), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL),
M. Stamatikos (NASA/ORAU), T. N. Ukwatta (GSFC/GWU) and
L. Vetere (PSU) report on behalf of the Swift Team:

At 23:38:12 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 081017 (trigger=331964).  This was too close to the Sun
for Swift to slew to.  The BAT on-board calculated location is 
RA, Dec 230.180, -32.815 which is 
   RA(J2000) = 15h 20m 43s
   Dec(J2000) = -32d 48' 53"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is usual for an image trigger, the immediately
available BAT light curve shows no obvious variation. 

Due to an observing constraint, Swift cannot slew to the BAT position. 
There will thus be no XRT or UVOT data for this trigger. 

Burst Advocate for this burst is O. Godet (og19 AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

P. D'Avanzo, S. Covino, L.A. Antonelli, D. Malesani, D. Fugazza, L.  
Calzoletti,  S. Campana, G.  Chincarini, M.L. Conciatore, S. Cutini, V. 
D'Elia,  F. D'Alessio, F.  Fiore, P. Goldoni, D. Guetta,  C. Guidorzi, 
G.L. Israel, E. Maiorano, N. Masetti, A. Melandri, E. Meurs, L. 
Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L.  Stella, G.  Stratta, 
G. Tagliaferri, G. Tosti, V.Testa, S.D. Vergani, F. Vitali report on 
behalf of the REM team:

The robotic 60-cm REM telescope located at La Silla (Chile) observed 
automatically the field of the GRB 081017 (Godet et al. GCN 8388
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 ) on Oct 
17 starting about 6.5 min after the burst.  Observations were carried 
out at high airmass. In a series of 10s and 30s exposures, at we do not 
see the any clear afterglow candidate inside the BAT error box down to R 
 > 17.0 and H > 15.5 (3sigma c.l.).

J. Tueller (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
O. Godet (U Leicester), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 081017 (trigger #331964)
(Godet, et al., GCN Circ. 8388
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 ).  The BAT ground-calculated position is
RA, Dec = 230.209, -32.790 deg which is 
   RA(J2000)  =  15h 20m 50.1s 
   Dec(J2000) = -32d 47' 23.3" 
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 80%.
 
The mask-weighted light curve shows a broad lo-level emission with some
structure starting at ~T-70 and ending around T+400 sec.  The spacecraft slewed
to the next pre-planned observing target at T+400 sec such that the partial coding
of this burst location decreased to a small value.  As such the statisitical
error on the flux measurement increased to the point that we can only say
there is a hint of emission out to around T+700 sec.
T90 (15-350 keV) is 320 +- 50 sec (estimated error including systematics).
 
The time-averaged spectrum from T+0.0 to T+320.0 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.64 +- 0.23.  The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band
is 0.07 +- 0.01 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/331964/BA/