GCN Circular 301
Subject
GRB 990506 optical observations
Date
1999-05-08T17:33:10Z (26 years ago)
From
Paul Vreeswijk at U of Amsterdam <pmv@astro.uva.nl>
P.M. Vreeswijk and E. Rol (University of Amsterdam) report on behalf
of the Amsterdam/Huntsville GRB optical follow-up team:
We measured the object at RA 11:54:57.80, Decl -26:43:03.8 (J2000)
reported by Vrba et al. to be variable (GCN #300) in our Harris-R band
images, taken with the WIYN telescope at May 8.18 UT. We find R =
22.21 +/- 0.15 using an aperture size which is twice the seeing disk
of 1.05"). Our measurement was taken at about the same time as where
Vrba et al. report Rc > about 23. The data were calibrated using the
RUBIN 149 field of the Landolt catalog (Landolt et al. 1992, 104,
340). The value we find for the reference star at RA 11:54:51.6, Decl
-26:43:4.09 (J2000), R = 16.1 +/- 0.1 is in good agreement with the
Vrba et al. calibration for this star: R = 16.11.
Based on our result we believe the object is constant, but we urge
more observations to confirm/reject the variable nature of this
object.
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