GCN Circular 343

J. P. Halpern (Columbia U.), J. Parker (SwRI), L. Allen (U. Michigan),
and E. Costa (IAS/CNR, Rome) report on behalf of the MDM Observatory GRB
follow-up team:

"We imaged the field of the BeppoSAX fast X-ray transient 1SAX J0835.9+5118
(Piro GCN 333
Not found
 
 
; Gandolfi et al., IAUC 7174) in the R band on two consecutive 
nights using the MDM 2.4m telescope.  Total exposure time was 50 minutes on 
May 21.19 UT and 40 minutes on May 22.19 UT.  Seeing was 1.5-1.6 arcsec on
the first night, and 1.8-2.2 arcsec on the second night.  Limiting magnitudes
for 5 sigma detection are R = 23.5 on the first night and R = 22.1 on the
second night.  No variable object is found to the limit of R = 22.1 within
the 3' radius error circle.  Below  we list magnitudes of objects referred
to in previous circulars: the radio source of Frail et al. (GCN 337
Not found
 
 
), and 
the galaxy described by Pedersen et al. (GCN 340
Not found
 
 
).  We adopt here the 
photometric calibration of Henden et al. (GCN 339
Not found
 
 
).

Radio Source     B = 21.58 +/- 0.08 (May 21.15 1.3m)
                 R = 20.81 +/- 0.05 (May 21.19 2.4m)
                 R = 20.69 +/- 0.07 (May 22.19 2.4m)

Pedersen Galaxy  B = 20.62 +/- 0.09 (May 21.15 1.3m)
                 R = 19.63 +/- 0.03 (May 21.19 2.4m)
                 R = 19.62 +/- 0.09 (May 22.19 2.4m)
		
The B magnitude of the radio source differs from the value given in our
GCN 338
Not found
 
 
 in part because of a 0.5 magnitude difference between the USNO-A2.0
values and the new calibration of Henden et al. (GCN 339
Not found
 
 
).  However, the
magnitude of the radio source given as R = 21.21 +/- 0.06 by Luginbuhl et al.
(GCN 341
Not found
 
 
) might indicate a significant discrepancy, assuming that the same 
calibration is being used.

With regard to the morphology of the Pedersen et al. galaxy, although our
images have inferior seeing, the object in question appears consistent in
both magnitude and shape on our May 21 image, including a faint extension 
in the same place as their point-like source.

This message may be cited."