GCN Circular 319

G. Pietrzynski and A. Udalski (Warsaw University Observatory) report on
behalf of the OGLE microlensing survey team:

Observations of the optical counterpart of GRB 990510 collected with the
1.3-m Warsaw telescope at the Las Campanas Observatory (Chile) on  May
11/12, 1999 indicate that the object faded smoothly to V=21.2 and I=20.3
on May 12.4 UT. 

Single observation in the B-band collected on May 11.3607 UT yields the
following colors of the GRB990510 counterpart: B=20.47+/-0.05,
B-V=0.54+/-0.06 and V-I=0.88+/-0.04. This indicates significantely
different spectral distribution as compared to regular stars.

The nearby galaxy, mentioned by Kaluzny et al 1999 GCN #314, is clearly
visible on collected frames. 

Updated photometry of the optical counterpart of GRB 990510 and light
curves are available from the OGLE Internet archive: 

http://www.astrouw.edu.pl/~ftp/ogle


[GCN OP NOTE (12May99):  Due to a problem in processing this Circular,
the NUMBER was erroneously assigned to be 318, when in fact it
should have been 319.  The archive copies have been fixed.]