GRB 080702A
GCN Circular 7923
Subject
GRB 080702A: Enhanced Swift-XRT position
Date
2008-07-02T19:59:51Z (17 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 95 s of overlapping XRT Photon Counting mode and UVOT
data for GRB 080702A, 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 = 313.05081, +72.31271 which is equivalent
to:
RA (J2000): 20h 52m 12.20s
Dec (J2000): +72d 18' 45.8"
with an uncertainty of 1.9 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.
GCN Circular 7925
Subject
GRB 080702A: Swift-XRT Team refined analysis
Date
2008-07-02T21:03:07Z (17 years ago)
From
Kim Page at U.of Leicester <kpa@star.le.ac.uk>
K.L. Page (U. Leicester) & M. De Pasquale (UCL-MSSL) report on behalf of
the Swift-XRT team:
We have analysed the first 3 orbits of Swift-XRT data obtained for GRB
080702A (De Pasquale et al., GCN Circ. 7920), covering 5.2 ks of Photon
Counting mode data, between ~75 and 12.6 ks after the trigger. The
UVOT-enhanced XRT position was given by Goad et al. in GCN Circ. 7923.
The light-curve can be modelled by a broken power-law, with a flat decay
of alpha = 0.5 +/- 0.3 until around the end of the first orbit of data. At
this point, the decay steepens to 1.6 +0.9/-0.3. The afterglow is already
faint by the end of the third orbit.
A spectrum extracted from the first orbit of data can be modelled with an
absorbed power-law, with Gamma = 2.05 +0.71/-0.64 and NH = (6.2
+5.4/-3.6)x10^21 cm^-2, in excess of the Galactic column in this direction
of 1.53x10^21 cm^-2. The observed (unabsorbed) flux over this time
interval (75-800 s post-trigger) is 5.7x10^-12 (1.0x10^-11) erg cm^-2
s^-1.
If the light-curve continues to decay with alpha ~ 1.6, the count rate 24
hours after the burst is estimated to be 3.3x10^-5 count s^-1, which
corresponds to an observed flux of 2x10^-15 erg cm^-2 s^-1.
This is an official product of the Swift-XRT team.
GCN Circular 7926
Subject
GRB 080702A, Swift-BAT refined analysis
Date
2008-07-02T21:52:54Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
H. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL),
M. De Pasquale (UCL-MSSL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-120 to T+182 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 080702A (trigger #315710)
(De Pasquale, et al., GCN Circ. 7920). The BAT ground-calculated position is
RA, Dec = 313.049, 72.278 deg, which is
RA(J2000) = 20h 52m 11.8s
Dec(J2000) = +72d 16' 39.7"
with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 81%.
The mask-weighted light curve shows a weak single spike.
T90 (15-350 keV) is 0.5 +- 0.2 sec (estimated error including systematics).
The time-averaged spectrum from T-0.0 to T+0.5 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.34 +- 0.42. The fluence in the 15-150 keV band is 3.6 +- 1.0 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.22 sec in the 15-150 keV band
is 0.7 +- 0.2 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/315710/BA/
GCN Circular 7929
Subject
GRB 080702A: MITSuME Akeno optical upper limits
Date
2008-07-03T00:07:25Z (17 years ago)
From
Nobuyuki Kawai at Tokyo Tech <nkawai@hp.phys.titech.ac.jp>
Y.A. Mori, T. Shimokawabe, Y. Kudou, H. Nakajima and N. Kawai (Tokyo
Tech) report on behalf of the MITSuME collaboration:
The 3-color 50cm MITSuME Telescope at Akeno, Japan, responded to GRB
080702A (de Pasquale et al. GCN 7920) at 43 sec after the trigger,
though we obtained the first sky image 20 min after the trigger
due to the poor sky condition with frequent cloud coverage.
In the co-added images of Ic, Rc, and g' bands, we did not detect any
afterglow candidate in the XRT error circle. The 3-sigma limiting
magnitudes based on USNO-B1.0 (I-band) and NOMAD (R-band,g'-band)
stars are following.
Filter start UT end UT Exposure LimitMag
---------------------------------------------------
g' 12:16:37 13:11:35 23 x 60 s 16.6
Rc 12:16:37 13:11:35 23 x 60 s 17.7
Ic 12:16:37 13:11:35 23 x 60 s 16.5
---------------------------------------------------
GCN Circular 7932
Subject
Swift/UVOT observation of GRB080702A
Date
2008-07-03T11:42:40Z (17 years ago)
From
Massimiliano de Pasquale at MSSL-UCL <mdp@mssl.ucl.ac.uk>
M. De Pasquale (MSSL/UCL) on the behalf of the
Swift/UVOT team:
The Swift/UVOT began settled exposures of the field of
GRB080702A 73s after the BAT trigger (De Pasquale et al.,
GCN Circ. 7920). We do not find any newsource in any
of the exposures inside the enhanced XRT error circle
(Goad et al., GCN Circ. 7923).
The 3-sigma upper limits for detecting a source in the
first finding chart (FC) exposure and co-added frames are:
Filter T_start(s) T_stop(s) Exp(s) Mag (3-sigma UL)
white (FC) 73 172 98 >20.8
white 674 5688 314 >21.4
v 179 578 393 >20.0
v 713 6099 305 >19.8
b 659 6840 334 >20.8
u 634 6714 432 >20.6
uvw1 610 6509 432 >20.2
uvm2 585 6303 432 >20.3
uvw2 689 5894 235 >20.3
The values quoted above are not corrected for the expected
high Galactic extinction corresponding to a reddening of
E(B-V) = 0.67 mag in the direction of the burst (Schlegel et
al. 1998).
GCN Circular 7934
Subject
No radio detection from the short GRB 080702A
Date
2008-07-03T14:34:32Z (17 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on
behalf of the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the Very Large Array to observe the field of view toward GRB
080702A (GCN 7920) at a frequency of 8.46 GHz on 2008 July 03.33 UT.
The GRB radio afterglow is undetected and the peak radio flux at the
XRT afterglow position (GCN 7923) is -22 � 52 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 7977
Subject
GRB 080702A: optical upper limit
Date
2008-07-14T14:40:04Z (17 years ago)
From
Giuseppe Greco at U Bologna <giuseppe.greco2@studio.unibo.it>
G. Greco (Bologna University), F. Terra (Second University of Roma "Tor
Vergata"), C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University),
F. Munz, G. Pizzichini (INAF/IASF Bologna), D. Nanni (INAF/OAR and Second
University of Rome "Tor Vergata"), I. Bruni (Bologna Observatory) report:
We observed the field of GRB 080702A (GCN 7920, de Pasquale et al.)
with the 152 cm telescope located in Loiano under
clear sky conditions (seeing~2").
By adding three consecutive 10 min exposures in the Rc filter
at mean time 2008 July 02.996 UT we do not detect any afterglow
candidate in the XRT error circle (GCN 7923, Goad et al.).
Our 3-sigma limiting magnitude is R~21 (based on Nomad1 catalogue).
The image has been posted in our public directory
from where it can be retrieved by sftp using
hostname: ermione.bo.astro.it
username: publicGRB
password: GRB_bo.
directory: GRB080702A