TITLE:   GCN CIRCULAR
NUMBER:  3255
SUBJECT: GRB 050412: optical observations
DATE:    05/04/12 23:46:02 GMT
FROM:    Alberto Castro-Tirado at LAEFF-INTA  <ajct@laeff.esa.es>

M. Jelinek, A. de Ugarte Postigo, V. Casanova,
J. Gorosabel and A. J. Castro-Tirado (IAA-CSIC, Granada)

report:

Following the detection by SWIFT of GRB 050412 (Cummings
et al. GCN Circ. 3237) we have observed the error box
with the 1.5m IAA's telescope at Observatorio de Sierra
Nevada in southern Spain. We have obtained 28 x 120s
images in the R-band under good seeing conditions (1.3")
starting on 12.833 Apr (i.e. 14.55 hr after the event).

We confirm the presence of an object mentioned by
Jensen et al. (GCN Circ. 3243) and Fox et al. (GCN Circ.
3244) at coordinates:

RA: 12:04:25.06  DEC: -01:12:03.6    (J2000).

Expected astrometric uncertainty is 0.5". We find a
preliminary magnitude of the object to be R = 22.75
+/- 0.14 compared to USNO-A2 stars, implying that the
object has not faded in brightness significantly, i.e.   
it might be unrelated to GRB 050412.  We also notice
that it is 9" from the SWIFT/XRT error box (5" error
radius) provided by Mangano et al.(GCN Circ.3253)."

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