GCN Circular 594
Subject
GRB 000301C: K' Observations
Date
2000-03-06T06:53:23Z (25 years ago)
From
Andrew S. Fruchter at STScI <fruchter@stsci.edu>
A. Fruchter and J. Rhoads (STScI) report:
The field of the presumed afterglow of GRB 000301C was re-oberved with
the NASA IRTF and NSFCam in the K' band (2.1) microns on UT March
5.61. We use our calibration from GCN 586 and comparison to the
brighter star ~6" to the W for photometry. We find that the presumed
OT is now fainter than the reference star by 2.04 mag, so that
K'=18.00. The formal error from photon statistics is 0.05 mag. The
total error on the relative magnitude might be as large as 0.07 mag,
and the total error on the absolute magnitude as large as 0.10 mag.
Relative photometry of five other sources in the field shows no
variation with respect to the bright star greater than 1.5 sigma.
The transient has therefore declined by 0.35 +- 0.08 mag in K' between
UT 4.64 March and 5.61 March. This is in contrast with a decline of
0.13 +/- 0.05 mags between 3.55 and 4.64 March (GCN 586 and 587).
The slow-down in the rate of decline in the R band over the same time
span (Veillet GCN 588) suggests a remarkable decoupling of the optical
and near-infrared behavior of this transient.
The candidate host is 1" W (not E as incorrectly reported in GCN 586)
and 2"N of the OT. It is the same object reported by Veillet in GCN
592. This galaxy has colors of order R-K'=5, J-K'=1; however, the
color must be considered highly uncertain until better comparison of
the optical and infrared images can be made.