GCN Circular 3253
Subject
GRB 050412: early Swift XRT analysis results
Event
Date
2005-04-12T19:10:35Z (21 years ago)
From
David Burrows at PSU/Swift <dxb15@psu.edu>
V. Mangano (IASF/Palermo), M. Capalbi (ASDC), C. Pagani (INAF-OAB), M. Goad
(U. Leicester), J. Kennea and D. Burrows (PSU) report on behalf of the
Swift XRT team:
We have analyzed the Swift XRT data from the first orbit observation of GRB
050412 (Tamburelli et al., GCN3241). The new refined coordinates are:
RA(J2000) = 12h 04m 25.5s
Dec(J2000) = -01:12:00.2
This position is 65.6 arcseconds from the refined BAT position given in GCN
3251 (Tueller et al. 2005) and 3.6 arcsec from the preliminary XRT position
(GCN3241). We estimate an uncertainty of 5 arcseconds radius (90% containment).
The [0.2-10] keV light curve in Windowed Timing (WT) and Photon Counting
(PC) mode starts ~100 seconds from the BAT trigger (T0). We clearly detect
a rapidly fading source.
A preliminary spectral fit to the WT data gives a spectral power law photon
index of 1.35 +/- 0.2 in the [0.5-10] keV band, assuming Galactic
absorption (2.21E20cm^-2). The average (~10000 seconds from trigger)
estimated unabsorbed 0.5-10 keV flux is then about 3.9E-12 erg cm^-2 s^-1.