[vsnet-grb-info 7792] GRB 090510: NOT afterglow confirmation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9338
SUBJECT: GRB 090510: NOT afterglow confirmation
DATE:    09/05/10 10:30:19 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at astro.ku.dk>

G. Olofsson, M. Ergon (Univ. Stockholm), D. Malesani, J.P.U. Fynbo 
(DARK/NBI), P. Jakobsson (Univ. Iceland), N.R. Tanvir, K. Wiersema 
(Univ. Leicester), A.J. Levan (Univ. Warwick), report on behalf of a 
larger collaboration:

We observed the field of short Swift/Fermi GRB 090510 (Hoversten et al., 
GCN 9331; Ohno & Pelassa, GCN 9334; Guiriec et al., GCN 9336) with the 
Nordic Optical Telescope equipped with ALFOSC. Observations were carried 
out in twilight and at high airmass (~3).

The candidate afterglow (Marshall & Hoversten, GCN 9332) is clearly 
detected in a stack of our images taken at a mean epoch May 10.215 UT 
(4.7 hr after the GRB). Calibrating against closeby USNO stars (R1 
magnitudes), we get R ~ 21.2. Comparing this value with the magnitude 
reported by Marshall & Hoversten (GCN 9332) indicates fading, thus 
confirming that this object is the afterglow of GRB 090510.

Astrometry of the field yields the following coordinates for the 
afterglow (0.4" error):

RA(J2000) = 22:14:12.64
Dec(J2000) = -26:35:02.8

which is consistent with the UVOT position. We note the presence of a 
fainter source ~1" East of the afterglow. A finding chart is posted at 
the following URL:

http://www.astro.ku.dk/~malesani/GRB/090510/090510_finder.png

We acknowledge the observiers at the NOT for carrying out this difficult 
observation.