[vsnet-grb-info 3462] GRB 060708: Swift-XRT refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5297
SUBJECT: GRB 060708: Swift-XRT refined analysis
DATE:    06/07/08 23:04:23 GMT
FROM:    Daniele Malesani at SISSA-ISAS,Trieste,Italy  <malesani at sissa.it>

S.D. Vergani (DIAS & DCU), C. Guidorzi (Univ. Bicocca & INAF-OABr), P. 
Romano (INAF-OABr), and A. Moretti (INAF-OABr), report on behalf of the 
Swift-XRT team:

We have analyzed the first two orbits of data of GRB 060708 (Moretti et 
al., GCN 5292). The XRT data set consists of 169 s exposure in windowed 
timing (WT) mode followed by 2.67 ks exposure in photon counting (PC) mode.

The refined position of the source is

  RA  (J2000) =  00h 31m 13.53s
  Dec (J2000) = -33d 45' 33.3"

with an uncertainty of 3.8 arcsec (90% containment).

This position is 4.0 arcsec from the XRT on board position, 2.9 arcsec 
and 4.1 arcsec from the XRT and UVOT positions respectively, reported by 
Moretti at al. (GCN 5292).

The 0.3-10 keV X-ray light curve shows a double broken power-law decay, 
starting with a steep segment (alpha ~ 4) that become shallower (alpha ~ 
0.8) after ~200 s from BAT trigger time.

The WT spectrum is fitted by an absorbed power law with photon index 3.3 
+/- 0.1 and N_H of about 1.5E21 cm^-2, in excess with respect to the 
Galactic value (1.8E20 cm^-2).

The PC spectrum is fitted by an absorbed power law with photon index 2.3 
+/- 0.1 and N_H of about 8.8E20 cm^-2.

Assuming alpha ~ 0.8, the extrapolated unabsorbed flux (0.3-10 KeV) at 
24 hours is 9.7E-13 erg cm^-2 s^-1.

This Circular is an official product of the Swift XRT Team.