GCN Circular 4598
Subject
GRB060124: detailed XRT analysis
Event
Date
2006-01-25T17:57:58Z (20 years ago)
From
Giancarlo Cusumano at INAF-IASFA <cusumano@pa.iasf.cnr.it>
T. Mineo (INAF-IASF), V. Mangano (INAF-IASF), V. La Parola
(INAF-IASF),G. Cusumano (INAF-IASF), J. Kennea (PSU), S. T. Holland
(GSFC/USRA), S.Hunsberger (PSU), J.Racusin (PSU), D. N. Burrows (PSU)
report on behalf of the Swift XRT team:
We have analyzed the Swift XRT data up to 0.55 days after the trigger
of GRB 060124 (Holland et al. GCN 4570) for a total exposure of about 11
ks.
The refined coordinates of the X-ray afterglow are:
Ra(2000) = 05 08 26.0
Dec (2000) = +69 44 26.7
with an estimated uncertainty is of 3.6 arcseconds radius (90%
containment).
This new position is 2.3 arcmin from BAT postion (Holland et al. GCN
4570); 6.7 arcsec from the position given by Mangano et al. (GCN 4578 )
based on 15 s observation in PC mode, and 0.6" from the position
given by Kong et al (GCN 4590). Moreover the refined coordinates are 2.7"
from the optical counterpart detected by Kann (GCN 4577).
The 0.2-10 keV light curve shows intense flaring activity during the
first orbit and a fading behaviour 10 ks after the trigger.
The light curve decay index in the interval 10-50 ks is -1.04+/-0.07.
The average spectrum accumulated during the first orbit (from 100 s to
1000 s after the trigger) is well fitted with a power law of photon
index 1.40+/-0.01, absorbed at lower energies by a column of (0.172 �
0.005)X10^22 cm^-2, higher than the galactic value (9.2X10^20 cm^-2) and
a 0.2-10 keV unabsorbed flux of 6.6E-09 ergs/cm^2/s. The average
spectrum accumulated during the decay part of the light curve (from 11
ks to 47 ks after the trigger) is well fitted with a power law with
photon index 2.1+/-0.1 and a 0.2-10 keV unabsorbed flux of 1.3E-11
ergs/cm2/s. If the burst continues decaying at the current rate we
estimate an XRT count rate of 0.05 counts/s at T+48hr, which corresponds
to an unabsorbed 0.2-10 keV flux of 3e-12 ergs/cm^2 s/1.