GRB 080714

M. Perri (ASDC), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC),
N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
J. P. Osborne (U Leicester), D. M. Palmer (LANL),
D. Perez (U Leicester), B. Preger (ASDC), P. Schady (MSSL-UCL),
M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester),
G. Stratta (ASDC), M. C. Stroh (PSU), D. E. Vanden Berk (PSU) and
L. Vetere (PSU) report on behalf of the Swift Team:

At 17:52:56 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080714 (trigger=316910).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 188.109, -60.279 which is 
   RA(J2000) = 12h 32m 26s
   Dec(J2000) = -60d 16' 42"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 40 sec.  The peak count rate
was ~5000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 17:54:16.4 UT, 79.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 188.10733, -60.27708 which
is equivalent to:
   RA(J2000)  = 12h 32m 25.76s
   Dec(J2000) = -60d 16' 37.5"
with an uncertainty of 3.1 arcseconds (radius, 90% containment). This
location is 7.5 arcseconds from the BAT onboard position, within the
BAT error circle. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
5.44e+21 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 5.01e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm)
filter starting 89 seconds after the BAT trigger. No afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle.  Because of the density of catalogued stars, further
analysis is required to report an upper limit for any afterglow in the
sub-image.    No correction has been made for the large, but uncertain extinction
expected. 

Burst Advocate for this burst is M. Perri (perri AT asdc.asi.it). 
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.)

S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), J. Cummings 
(GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), M. Perri (ASDC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta 
(GWU)
on behalf of the Swift-BAT team:

Using the data set from T-240 to T+963 sec from the recent telemetry 
downlink,
we report further analysis of BAT GRB 080714 (trigger #316910)
(Perri, et al., GCN Circ. 7978
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 ).  The BAT ground-calculated position is
RA, Dec = 188.104, -60.274 deg which is
   RA(J2000) = 12h 32m 24.9s 
   Dec(J2000) = -60d 16' 28.2"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The
partial coding was 43%. 

The mask-weighted lightcurve shows a single peak with a rise time of about
3 seconds and an exponential decay with a time constant of about 10 
seconds. 
T90 (15-350 keV) is 33 +- 9 sec (estimated error including systematics).
There is a small peak in the raw light curve, mostly above 25 keV, at about
T-90 sec that appears to be from a different source, out of the field of 
view.

The time-averaged spectrum from T-3.6 to T+50.3 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.52 +- 0.08. The fluence in the 15-150 keV band is 2.5 +- 0.1 x 10^-06 
erg/cm2.
The 1-sec peak photon flux measured from T-0.37 sec in the 15-150 keV band
is 4.2 +- 0.3 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/316910/BA/

M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 4736 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 080714, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 188.10601, -60.27775 which is equivalent
to:

RA (J2000): 12h 32m 25.44s
Dec (J2000): -60d 16' 39.9"

with an uncertainty of 2.3 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest position
can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is
described by Goad et al. (2007, A&A, 476, 1401
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an
extension of this method.

This circular was automatically generated, and is an official product of the
Swift-XRT team.

G. Stratta, M. Perri, B. Preger (ASDC) report on behalf of the
Swift-XRT team:

We analysed the first 3 orbits of XRT data for GRB 080714 (Perri et al.,
GCN Circ. 7978
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 ) taken from 88s after the trigger (T0) in Windowed Timing
(WT)
mode and then in Photon Counting (PC) mode from T0+233 s to T0+9874 s.
The UVOT-enhanced XRT position was given by Goad et al. (GCN Circ. 7980
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 ).

The X-ray light curve from T0+88s up to ~T0+300s shows an initial 40 seconds
long flat segment followed by an increasingly steepening decay. Starting
from
T0+300s (PC data) the light curve can be fit with a power law model with a
best fit slope of 1.0+/-0.1.

The WT data spectrum from T0+88s to T0+231s is well fitted by an absorbed
power law model with photon index Gamma=1.14+/-0.05 and a total equivalent
hydrogen column density of NH=(0.3+/-0.1)e22 cm**-2. The Galactic NH is
5.44e21 cm**-2 (Kalberla et al. 2005). The 0.3-10 keV observed (unabsorbed)
flux is (3.4+/-0.2)e-10 erg/cm**2/s ((3.9+/-0.2)e-10 erg/cm**2/s).

If the light-curve continues to decay with the same rate, the count rate
24 hours after the trigger is estimated to be ~6e-3 counts/s, which
corresponds to an observed flux of ~5e-13 erg/cm**2/s.

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

F.E. Marshall (NASA/GSFC) and M. Perri (ASDC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT observed the field of GRB 080714 starting 90 s after
the BAT trigger (Perri et al., GCN Circ. 7978
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 ).  The burst is in
a crowded field only 2.5 degrees from the Galactic Plane. 
We find a fading source inside the enhanced XRT error circle 
(Goad et al., GCN Circ. 7980
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 ) in observations with the White and 
V filters. The preliminary position for the afterglow is:

  RA(J2000)  =  12:32:25.44 = 188.1060
  DEC(J2000) = -60:16:40.4  = -60.2779

with a 90% confidence error radius of about 0.8 arcsec.

The measured magnitudes in the UVOT photometric system (Poole et al.
2008, MNRAS, 383, 627) and 3-sigma upper limits for detecting
a source in the first two finding chart (FC) exposures and 
subsequent co-added exposures are:

Filter          T_start(s)   T_stop(s)      Exp(s)       Mag 

white (FC)          90          189           98         20.2 +/- 0.2
white             4290         4489          197        >20.7
v (FC)             197          596          393         19.1 +/- 0.2
v                 5896         6095          197        >19.7
b                  677         4284          206        >20.2
u                  652        12382         1137        >20.7
uvw1               628         6505          236        >19.7
uvm2               602         6300          236        >19.9
uvw2               707        16498         1007        >20.8

The values quoted above are not corrected for the predicted large, but uncertain,
Galactic extinction the direction of the burst (Schlegel et al. 1998).

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team report:

The long GRB 080714 (Swift-BAT trigger
#316910: Perri et al., GCN 7978
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 , Barthelmy et al., GCN 7979
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 ) triggered
Konus-Wind at T0=64378.478 s UT (17:52:58.478).

The burst light curve shows a single pulse with a duration of ~20s.

As observed by Konus-Wind the burst
had a fluence of 3.64(-0.60, +0.87)x10^-6 erg/cm2,
and a 256-ms peak flux measured from T0+0.544 s
of 6.84(-1.79, +2.01)x10^-7 erg/cm2/s
(both in the 20 keV - 1 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+16.640 s) is well fitted (in the 20 keV-1 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.24(-0.39, +0.46)
and Ep = 137(-34, +100) keV (chi2 = 48.3/52 dof).

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

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.rssi.ru/LEA/GRBs/GRB080714_T64378/

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

We observed the field of GRB 080714 (Swift trigger 316910; M. Perri et
al., GCN #7978
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 ) in two epochs, simultaneously in g'r'i'z'JHK with GROND
(Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope
at La Silla Observatory (Chile). 

We detect the optical afterglow reported by Marshall & Perri (GCN #7982
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 ) at 

RA (J2000.0) = 13h 32m 25.49s
DEC (J2000.0) = -60d 16' 39.3" 

with an absolute uncertainty of 0.6". 

Preliminary photometry yields the following magnitudes against USNO-B1 and
2MASS field stars in stacked images: 


Band  T_mid(h)     Exp(min)   Mag 

g'    6.4058       50         > 24.3
g'    30.3847      32         > 23.4
r'    6.4058       50         22.76 +- 0.08
r'    30.3847      32         > 23.6
i'    6.4058       50         21.15 +- 0.07
i'    30.3847      32         22.68 +- 0.24
z'    6.4058       50         20.39 +- 0.06
z'    30.3847      32         21.82 +- 0.29
J     6.2827       40         18.58 +- 0.11
J     30.2958      30         20.00 +- 0.16
H     6.2827       40         17.25 +- 0.14
H     30.2958      30         18.52 +- 0.24 

not corrected for the expected Galactic foreground reddening of around
E(B-V) =  1.15 mag (Schlegel et al., 1998).
Given the high foreground extinction, the non detection in g' is
consistent with the powerlaw slope of the broad band SED derived from r to
H and does not necessarily imply a high redshift. 

Additionally, we note the presence of a nearby, faint (r'~ 24.1 +- 0.2)
source at 

RA (J2000.0) = 13h 32m 25.60s
DEC (J2000.0) = -60d 16' 37.7" 

roughly 1.8" away from the afterglow, which may influence the photometry
in the second epoch.