Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 4565

GRB 060121: Swift XRT refined analysis
2006-01-22T18:46:38Z (18 years ago)
Pat Romano at OAB-Swift <>
V. Mangano, V. La Parola, T. Mineo (INAF-IASFPA), P. O'Brien (UL),
P. Romano (INAF-OAB), D.N. Burrows (PSU), M. Chester (PSU),
L. Angelini (GSFC) on behalf of the Swift XRT team:

The Swift XRT instrument began observing the HETE-discovered GRB 050121
(Arimoto et al., GCN 4550; Prigozhin et al., GCN 4551) at 01:21:37 UT
on 22 January 2006 (Mangano et al., GCN 4560) 10.6 ks after the burst.

Further analysis of the first 5 ks of XRT data of GRB 060121
spanning three orbits (Mangano et al., GCN 4560)
revealed that the source is fading with a power law decay index
of -1.08 + / - 0.24.

The average spectrum is well fitted by an absorbed power law
model with a photon index of 2.07 + / - 0.25 (90% confidence level).
The best fit absorption column of (7.8 + / - 4.5)e20 cm^-2 is
slightly in excess of the Galactic absorption column of 1.7e20 cm^-2.
The average unabsorbed 0.2-10 keV flux in the time range
10.6 - 22 ks after the trigger is at the level of
4.6e-12 ergs cm^-2 s^-1.
The predicted flux at 24 hours after the trigger is at the
level of 6.8e-13 ergs cm^-2 s^-1 (corresponding to a count rate
of about 1.1e-2 counts/s).
New observations are being performed. 

According to NED, the nearest two galaxies with known redshifts
are SDSS J091016.39+453819.9 and SDSS J091023.53+454159.8 with a
redshift of 0.154357 and 0.154272, respectively.
They are 4.5 and 6 arcmin from the Swift GRB position
(Mangano et al., GCN 4560).
Looking for U.S. government information and services? Visit