GCN Circular 7810

B. Sbarufatti, V. Mangano, V. La Parola (INAF-IASF Pa) report on behalf
of the Swift-XRT team

The Swift XRT began observations of the INTEGRAL burst GRB 080603A
(Paizis et al., GCN Circ 7790) on June 3, 14:11 UT, 173 minutes after
the trigger. The data consist of 3.9 ks observed in Photon Counting
mode.

We detect an X-ray counterpart at position (astrometrically corrected 
using the XRT-UVOT alignment and matching UVOT field sources to the 
USNO-B1 catalogue): RA, Dec = 279.40858, 62.74446 which is equivalent to:

RA (J2000):  18 37 38.06
Dec (J2000): +62 44 40.1

with an uncertainty of 1.9 arcsec (radius, 90% confidence).
The light curve is dominated by a flare-like structure which covers all
the observed time interval, making it impossible to estimate the
behaviour of the underlying continuum and to predict the evolution of
the source.
The spectrum can be fitted with a powerlaw with an intrinsic absorbing
column of (8+/-5)e21 cm-2 at z=1.688 (Perley et al., GCN Circ 7791)
and photon index 2.4 �0.3. The observed (unabsorbed) 0.3-10 keV flux
is 3.23 (3.57)e-12 erg cm-2 s-1.

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