GCN Circular 6920
Subject
GRB 071010B: Photometry after 1.6 days
Date
2007-10-16T01:37:25Z (17 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
M. Im, I. Lee (Seoul National University), and Y. Urata
(Saitama University) on behalf of the EAFON team:
Using the Mt. Lemmon (Arizona, US) 1.0m telescope
operated by the Korea Astronomy Space Science Institute,
we continued our observation of GRB071010B (GCN 6871,
Markwardt et al.), beginning at 11:37:19 UT on Oct 12,
or 1.62 days after the trigger.
From a stacked image of nine, 5 min frames in the R-band,
we detect the OT again (Oksanen GCN 6873, Kann et al. GCN 6884).
A preliminary photometry of the object using the standard
star data taken during the same day is given below
(aperture mag with 6" diameter circle). Also given is a
slightly revised R-band magnitude we reported earlier
(Im et al., GCN 6897).
t_start (UT) Filter exp (sec) R-mag err
-----------------------------------------------------
Oct. 11,
11:19:47 R 4x300 19.81 0.08
Oct. 12,
11:37:19 R 9x300 20.54 0.10
Our result is consistent with the recent report that
the GRB is fading rather slowly (GCN 6918, Kann et al.;
GCN 6919 Kocevski et al.). However, compared with
the magnitudes at Oct. 14 reported by Kann et al. (6918),
our photometry suggests a very marginal decrease in
the brightness between Oct. 12 - Oct. 14.
We will report later, the BVRI photometry data
taken during the same period.
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