GCN Circular 669
Subject
GRB 000418, Optical observation
Date
2000-05-12T11:20:41Z (24 years ago)
From
Mark R. Metzger at CIT <mrm@astro.caltech.edu>
M. R. Metzger (Caltech) and A. Fruchter (STScI) report:
"The suggested afterglow candidate for GRB 000418 (Klose et al. GCN645)
was imaged in the R band with the Keck I telescope + LRIS on UT May 6.42.
We measure R = 23.57 +- 0.10 for the object at this epoch. When combined
with the photometry of Mirabal et al. (GCNs 646, 650, 653), this suggests
that the decay rate has steepened to a t ^ -1.2 power law from the
shallower slope of the early photometry. We also note that in our stacked
image having approx. 0".6 FWHM seeing, the candidate PSF does not appear
extended (is consistent with a point source PSF). This suggests that the
continuum emission is still dominated by the afterglow, or that the
underlying host galaxy (cf. Bloom et al. GCN 661) is compact.
This message may be cited."