GRB 080702B

P.A. Evans (U. Leicester) and M. de Pasquale (MSSL/UCL) report on behalf
of the Swift team.

Swift has reobserved the field of GRB 080702B (Cummings et al. GCN Circ.
7924
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 ) in two pointings on 2008 July 8 and 2008 July 10 (six and eight
days after the burst respectively), obtaining 7 ks of data in total.

The second X-ray source reported in our previous circular (Evans et al.
(GCN Circ 7931
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 ) is not detected in these data, with a 3-sigma
upper limit of 1.3e-3 counts per second. The count-rate in the initial
observation was (5.4 +/- 1.8)e-3 counts per second, thus the source has
faded.

We therefore conclude that this was the afterglow of GRB 080702B.

This circular is an official product of the Swift-XRT team.

C. Clemens, S. Loew, J. Greiner, A. Yoldas, T. Kruehler (all MPE Garching), A. 
Kupcu Yoldas (ESO) and G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching) 
report on behalf of the GROND team:

We observed the field of GRB 080702B (Swift; Cummings et al., GCN #7924
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 ) 
simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) 
mounted at the 2.2 m ESO/MPI telescope at La Silla Observatory (Chile).

Observations started at 09:14 UT on July 3rd, 2008, 32.1 hr after the GRB 
trigger with 53.6 min of effective exposures in g'r'i'z' and 56.0 min in JHK. 
They were carried out at an average seeing of 0.9".

We do not detect any object at the position of the 2nd XRT source within the 
6.3'' error circle reported by Evans et al. (GCN #7931
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 ) to the following 3 
sigma (optical) and 6 sigma (infrared) upper limits:

g' > 24.6 mag,
r' > 24.5 mag,
i' > 23.6 mag,
z' > 23.3 mag,
J > 22.0 mag,
H > 21.0 mag and
K > 19.0 mag.

Given upper limits are calibrated against USNO-B1 as well as 2MASS field 
stars.

C. Markwardt (GSFC/UMD), S. D. Barthelmy (GSFC),
W. Baumgartner (GSFC/UMBC),A. Copete (Harvard), J. Cummings (GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), J. Grindlay (Harvard),
H. Krimm (GSFC/USRA),K. McLean (GSFC/UMD), D. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. Ukwatta (GWU)
On behalf of the Swift-BAT and BATSS teams:


Using the event data from T-83 to T+37 seconds, we present further
analysis of GRB 080702B.  The best-determined position in BAT was
RA, Dec 355.616,  -5.424 (J2000) or

RA = 23h 42m 27.8s
Dec = -05d 25' 26.4"

with an uncertainty of 3.5 arcmin (radius, sys+stat, 90% containment).
The partial coding was varying (the entire burst occurred during a
preplanned Swift slew manuever), but was approximately 60% during
the entire burst.

The mask-weighted light curve shows a single peak with a few
second rise, and slow decay.  T90 was 20 +- 3 seconds (estimated
error including systematics). 

The time-averaged spectrum from T-2 to T+21 seconds is best fit by a
simple power-law model.  The power law index of the time-averaged
spectrum is 1.44 � 0.13.  The fluence in the 15-150 keV band was
(5.0 � 0.9) x 10^-7 ergs/cm2/s.  The 1-sec peak photon flux measured
from T+4 sec in the 15-150 keV band was 0.5 +- 0.1 photons/cm2/s. 
All the quoted errors are at the 90% confidence level.

E. Berger (Princeton/OCIW) and B. Madore (OCIW) report:

"Starting on 2008 July 2.36 UT we observed the BAT error circle of GRB 
080702b (GCN #7924
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 ) using the du Pont 100-inch telescope at Las Campanas 
Observatory.  A total of 1500 sec were obtained in R-band in good seeing 
conditions (0.9").  A comparison to DSS reveals no new sources to the 
limit of the survey.  Further observations are planned."

P.A. Evans (U. Leicester), P. Schady and M. de Pasquale (MSSL-UCL)
report on behalf of the Swift team:

Swift began observing the field of GRB 080702B (Cummings et al. GCN circ
7924
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 ) at 2008 July 02 at 17:38 UT, 17.3 hours after the burst. In 4 ks
of XRT data we do not detect any sources within the refined error circle
presented in GCN Circ 7924
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 , down to a 3-sigma upper limit of 2.2 x 10-3
counts s-1.

There are two sources within the original error circle in GCN Circ 7924
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 .
The brightest lies at RA, Dec=355.6326, -5.5318 degrees, with an
estimated uncertainty of 4.7" (radius, 90% confidence). This is
coincident with a known optical source, and is not fading; this is
thus not the GRB afterglow.

The second object lies at RA,Dec=355.5665, -5.51410, which is equivalent
to:

RA (J2000)  = 23 42 15.95
Dec (J2000) = -05 30 50.8

with an estimated uncertainty of 6.3" (radius, 90% containment). The
source count rate is around 3e-3 counts per second, and we are  unable
to determine at present whether this source is fading.

In 3.7 ks of UVOT data obtained using the White filter, no new sources are
detected. The 3-sigma upper limit at the position of the second XRT source
is 22.4 mag.


This circular is an official product of the Swift team.

Jay R. Cummings (NASA/UMBC), A. Copete (Harvard),
J. Grindlay (Harvard), D. Palmer (LANL),
for the Swift-BAT and BATSS teams


At 01:10:41, Swift-BAT observed GRB 080702B. The burst occurred
during a preplanned Swift slew maneuver. The rate increase was
noted during a routine check of the counting rates for missed out-
of-field and slew bursts. A GRB candidate was automatically 
detected by the BAT Slew Survey (BATSS) with 5.9 sigma in the 
S band (15-50 keV) and 6.5 sigma in the B band (15-150keV). 
The burst profile is FRED-like with ~3sec rise and ~30sec decay. 
The peak count rate is 0.05cts/sec (S band) and 0.04cts/sec (B band). 
BATSS automated analysis measured T90 = 10.5sec and T50 = 5.5sec, 
and a position 

RA = 23h 42m 24s, DEC = -05d 29' 23" 

with a 90% confidence radius of 6.4arcmin. 

Further ground analysis of this GRB yielded a location 
RA, Dec 355.616,  -5.424 (J2000) or

RA = 23h 42m 27.8s
Dec = -05d 25' 26.4"

with an estimated error radius of 3 arcmin. A Swift TOO request was 
submitted, and Swift/XRT and UVOT began observing at about 18:30, 
approximately 17.3 hours after the burst.