GCN Circular 4453
Subject
GRB 060108: Refined XRT analysis
Date
2006-01-09T11:56:40Z (18 years ago)
From
Kim Page at U.of Leicester <kpa@star.le.ac.uk>
K.L. Page, A.P. Beardmore, M.R. Goad, D.N. Burrows, J. Greiner (MPE) & D.
Hinshaw (GSFC-SPSYS) report on behalf of the Swift-XRT Team:
We have analysed the first 7 orbits of X-ray data for GRB 060108. A ~9ks
PC mode image gives a refined X-ray position of:
RA(J2000) = 09h 48m 01.6s
Dec(J2000) = +31d 55' 04.6"
with an estimated uncertainty of 3.4" (radius, 90% containment), including
corrections for the XRT boresight. This is 1.9" from the XRT position
given by Page et al. (GCN 4444) and 61" from the refined
(ground-calculated) BAT position (Sakamoto et al.; GCN 4445).
Spectra from both the first and later orbits of data are consistent with a
single power-law model, with Gamma = 1.76 +/- 0.19. There is no evidence
for absorption in excess of the Galactic value of 1.7e20 cm^-2. From the
first orbit of PC data (107-1072 seconds after the trigger), the 0.3-10
keV observed (unabsorbed) flux was calculated to be 1.08e-11 (1.13e-11)
erg cm^-2 s^-1.
The PC light-curve shows some slight flaring activity, with the underlying
continuum being well modelled by a broken power-law with parameters:
alpha_1 = 2.2 +/- 0.5
t_break = 280+/- 64 s
alpha_2 = 0.43 +/- 0.06
This predicts the observed (unabsorbed) flux at 24 hours after the burst
to be 9.8e-13 (1.0e-12) erg cm^-2 s^-1.