GCN Circular 670

GRB 000508B: Optical observations

B. L. Jensen, H. Pedersen, J. Hjorth (U. of Copenhagen),
J. P. U. Fynbo (U. of Aarhus/ESO),
J. Gorosabel, N. Lund (DSRI,Copenhagen),
H. Kjeldsen, F. Grundahl (U. of Aarhus),
C. Zurita, J. Casares (IAC,Tenerife),
C. Sanchez-Fernandez and A.J. Castro-Tirado (LAEFF, Madrid)
report on behalf of a larger European GRB collaboration:

"We have obtained images of the RXTE/IPN error box
reported by Smith et al. (GCN #665
Not found
 
 
) with the 2.56-m
Nordic Optical Telescope (NOT+ALFOSC) on La Palma,
and the 1.54-m Danish Telescope (DK-1.54m+DFOSC) at
La Silla, as follows:

Telescope      Date                  Filter/Exp t. FWHM
NOT       2000 May 10.14 UT (t+32h); I:5x300s;     FWHM=0.8"
DK-1.54m  2000 May 10.17 UT (t+33h); R:3x420s;     FWHM=1.5"
DK-1.54m  2000 May 10.38 UT (t+38h); R:3x420s;     FWHM=1.5"
DK-1.54m  2000 May 12.25 UT (t+83h); R:4x420s;     FWHM=1.3"

We have visually compared the combined May 10 2520s R-band
image with red POSS-II exposure. The three sets of May 10
images have been compared internally, both visually
and using automated routines based on DAOPHOT II/ALLSTAR
PSF-photometry. Additionally, we have compared the
combined May 10 and May 12 R-band images, visually and
through automated routines. We do not, in any of the
comparisons, find any significantly variable objects
down to a 3-sigma mag limit of R~22.5. We do not find
significant variability in the objects noted by Stanek
et al. (GCN #668
Not found
 
 
). An image of the error-box is
posted at http://www.astro.ku.dk/~brian_j/grb/grb000508B "