[vsnet-grb-info 4207] GRB070110: Swift XRT Team refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6008
SUBJECT: GRB070110: Swift XRT Team refined analysis
DATE:    07/01/10 19:11:47 GMT
FROM:    Vanessa Mangano at INAF-IASFPA  <vanessa at ifc.inaf.it>

B. Sbarufatti, V. Mangano, T. Mineo, G. Cusumano (INAF-IASFPA),
and H. Krimm (GSFC/USRA) report on behalf of the Swift XRT Team:


We have analysed the first five orbits of XRT data of GRB07011,
consisting of 171 s of exposure in Windowed Timing (WT)
mode and 10 ks of exposure in Photon Counting (PC) mode.

The XRT refined position from the PC data is:

   RA(J2000)  =  00h 03m 39.43s
   Dec(J2000) = -52d 58' 26.7s

with an error of 3.6 arcsec (90% containment). This is 45.3 arcsec
from the refined BAT position (Cummings et al., GCN 6007),
3.0 arcsec from the preliminary  XRT position and 1.9 arcsec
from the UVOT position (Krimm et al., GCN 6005).

The 0.3-10 keV light curve shows an initial steep decay with
slope -2.53 +/- 0.07 followed by a flat decay phase with slope
-0.05 +/- 0.04, that starts 580 +/- 43 s after the trigger.
After a further break at 20.3 +/- 0.8 ks from the trigger
the light curve steepens abruptly, with a slope -7.9 +/- 0.9.
A small flare is detected at about T+380 s.

The WT and PC spectra are well fit by an absorbed power law
with photon index 2.00 +/- 0.08.
The absorption is at the level of 3e20 cm^-2, consistent with
the Galactic absorpion along the light of sight (1.8e20 cm^-2).
The average unabsorbed flux of the WT and PC spectra is
7.0e-10 and 1.7e-11 erg cm^-2 s^-1 respectively.

If decaying at the present rate the source will reach a count rate
of 4e-6 counts/s  in the 0.3-10 keV  band at T+24 hr, which
corresponds to an unabsorbed 0.3-10 keV flux of 2e-16 erg cm^-2 s^-1.

All quoted errors are the 90% confidence level.

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