[vsnet-grb-info 7535] GRB 090404: NOT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9093
SUBJECT: GRB 090404: NOT observations
DATE:    09/04/05 03:21:10 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at astro.ku.dk>

D. Malesani, J.P.U. Fynbo (DARK/NBI), P. Jakobsson (Univ. Iceland), A.J. 
Levan (Univ. Warwick), T. Liimets (Tartu Obs. and NOT), and Z. Banhidi 
(Stockholm Obs.), report on behalf of a larger collaboration:

We observed the field of GRB 090404 (Ziaeepour et al., GCN 9086) with 
the NOT equipped with StanCam. Observations were carried out in the R 
and I bands, starting on 2009 Apr 5.035 UT (8.89 hr after the GRB). A 
total of 20 min exposure per filter were secured.

We do not detect any object inside the revised XRT error circle 
(Beardmore et al., GCN 9088), down to limiting magnitudes R > 23.5, I > 
22.3, assuming R = 19.19 and I = 18.84 for the USNO-B1 star 1255-0233978 
at RA = 15:57:00.24, Dec = +35:31:28.0.

We note the presence of a faint object (R = 22.8), possibly extended, 
just outside the XRT circle, at coordinates (J2000):

RA = 15:56:57.72
Dec = +35:30:58.2

This position is 2.4" away from the XRT error circle center, which has 
currently an error radius of 1.4" (from 
http://www.swift.ac.uk/xrt_positions/index.php). We cannot state whether 
this object is related to GRB 090404. Further observations are ongoing.