GCN Circular 88

GRB980519 Optical Observations with Keck and Palomar

R. R. Gal, J. S. Bloom, C. Steidel, K. L. Adelberger, S. G. Djorgovski, 
and S. R. Kulkarni, on behalf of the Caltech GRB Collaboration, report:

"We have obtained additional photometric CCD images of the field of 
GRB 980519. C. Steidel and K. Adelberberger have obtained 11 minutes of 
R-band data using the W.M. Keck Observatory 10-m, and R. Gal has
obtained 
800 sec. of i band data and 750 sec. of R band data with the Palomar 
Observatory 5-m on UT May 21. We measured magnitudes for the OT using
the 
Landolt magnitude system derived by Bloom et al.(GCN #87
Not found
 
 
) for the nearby 
stars. The OT is no longer visible in our i-band data, with an upper
limit of 
I > 21.6 +/- 0.7, at UT May 21.43. The OT is still seen in the R band
with 
R = 23.48 +/- 0.2 at UT May 21.469 (Palomar) and R = 23.10 +/- 0.13 at 
UT May 21.6 (Keck). The fainter Palomar magnitude at the earlier epoch
is 
likely due to poor seeing conditions (>2") which place the object close
to 
our detection limit.

C. Steidel and K. Adelberger also report that in seeing conditions
of 0.75" at Keck the OT is not distinguishable from a point source.

We note that these observations place an upper limit on the magnitude of
the 
OT host galaxy of not brighter than R ~ 24 mag.

Our R-band magnitudes are consistent with the source still fading with a
slope
of approximately 2.0, while the I-band data do not provide additional 
constraints on the slope.

This message may be cited."