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 5734

GRB 061019: SMARTS afterglow confirmation
2006-10-19T16:25:49Z (18 years ago)
Bethany Cobb at Yale U <>
B. E. Cobb (Yale), part of the larger SMARTS consortium, reports:

Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical/IR imaging of the error region of GRB 061019
(GCN 5728, Guidorzi et al.) with a mid-exposure time of
2006-10-19 07:29 UT, which is ~3.2 hours post-burst.
Total summed exposure times amounted to 15 minutes in I and V and
12 minutes in J and K.

Within the error region of the X-ray afterglow detection
(GCN 5729, Guidorzi et al.), we detect the source reported
by Covino et al. (GCN 5730), in the I, J and K bands.
The source is not detected in V, to a limiting magnitude
of ~22.  The preliminary magnitudes of this source
(calibrated against several 2MASS stars in IR and USNO-B1.0
stars in the optical) are:

time post-
burst (hrs)     I               J               K
3.2             20.2 +/- 0.3    17.6 +/- 0.1    15.4 +/- 0.1

(not corrected for the expected high Galactic extinction)

This indicates that the source has faded by ~1 magnitude
since the Covino et al. K-band observations, taken
~1.1 hours post-burst.  This source is therefore confirmed to
be the afterglow of GRB 061019, wth a decay rate of alpha ~ -0.8.

[GCN OPS NOTE(19oct06): Per author's request, the J-band value
was corrected from 17.9 to 17.6.]
Looking for U.S. government information and services? Visit