Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 10706

GRB 100420A: Gemini discovery of infrared afterglow
2010-04-29T22:01:47Z (14 years ago)
Andrew Levan at U.of Leicester <>
A.J. Levan (U. Warwick), A. Cucchiara  (PSU), N.R. Tanvir (U.
Leicester), D. Fox (PSU) report on behalf of a larger collaboration:

"We obtained two epochs of observations of GRB 100420A (Baumgartner
et al. GCN 10628) using Gemini-North/NIRI. Our first epoch consisted
of 540s of observations in each of YJH and K and began at April 20
13:24 UT, approximately 8.2 hours after the burst. Our second epoch
was obtained at April 22 14:27 ~57 hours after the burst.

Within the refined XRT error circle we find a single object in our
first epoch K-band observation. The object has a location of

RA(J2000) 19:44:30.57
Dec(J2000) 55:46:10.0

with an error of 0.3" in each axis. It has a magnitude of K~21 in
our first epoch observation, but has faded below our 3-sigma detection
limit of K~22 in the second epoch. We therefore identify this source
as the infrared afterglow of GRB 100420A.

The source is not significantly detected in our J or H-band observations 
to preliminary limiting magnitudes of H>21.5, J>22.5 (3 sigma). However, 
because of the relative faintness of the K-band observations these limits
are not constraining in terms of high-z and dust extinguished
afterglow models"
Looking for U.S. government information and services? Visit