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 8789

GRB 090107B: Swift-XRT detection of possible afterglow
2009-01-07T21:09:39Z (15 years ago)
Matteo Perri at ISAC/ASDC <>
M. Perri (ASDC) and P. Evans (U. Leicester) report on behalf of the
Swift-XRT team:

Swift began observing the field of the INTEGRAL GRB 090107B (Gotz et
al., GCN Circ. 8786) 4.2 ks after the trigger. A single uncatalogued
source was identified within the IBIS/ISGRI error circle.

Using 1314 s of XRT Photon Counting mode data and 2 UVOT images, we find
an astrometrically corrected X-ray position (using the XRT-UVOT alignment
and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec =
284.81750, 59.59510 which is equivalent to:

RA (J2000):  18 59 16.21
Dec (J2000): +59 35 42.3

with an uncertainty of 1.8 arcsec (radius, 90% confidence). The source
lies 21 arcsec from the IBIS/ISGRI centroid and has a count rate of
~0.25 counts/s during this observation.

Currently we cannot determine if this source is fading, and therefore
cannot confirm if this source is associated with GRB 090107B.
Observations of this source are on-going.

This circular is an official product of the Swift-XRT team.
Looking for U.S. government information and services? Visit