GCN Circular 11446

B. Sbarufatti (INAF/OAB-IASF Pa) reports on behalf of the Swift-XRT
team:

We have analysed 24 ks of XRT data for GRB 101204A (Cummings  et al.
GCN Circ. 11440
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 ), from 126.2 ks to 383.1 ks after the  BAT trigger. The
data are entirely in Photon Counting (PC) mode. Using 9912 s of PC mode
data and 4 UVOT images, we find an enhanced XRT position (using the
XRT-UVOT alignment and matching UVOT field sources to the USNO-B1
catalogue): RA, Dec = 167.53700, -20.41980 which is equivalent to:

RA (J2000): 11h 10m 8.88s
Dec(J2000): -20d 25' 11.5"

with an uncertainty of 1.6 arcsec (radius, 90% confidence).

The light curve can be modelled with  a power-law decay with a decay
index of alpha=1.33 (+0.24, -0.23).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.14 (+0.34, -0.18). The
best-fitting absorption column is  consistent with the Galactic value
of 3.3 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 3.4 x 10^-11 (3.9 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     3.3 (+4.4, -0.0) x 10^20 cm^-2
Galactic foreground: 3.3 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     2.14 (+0.34, -0.18)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020153.

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