[AAVSO-HEN] GRB 090313, GROND observations

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  8983
SUBJECT: GRB 090313, GROND observations
DATE:    09/03/13 10:34:51 GMT
FROM:    Sylvio Klose at TLS Tautenburg  <klose at tls-tautenburg.de>

A. C. Updike (Clemson University), S. Klose (Tautenburg), C. Clemens
and J. Greiner (MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 090313 (Swift trigger 346386; Mao et al. 
2009, GCN 8980) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 
2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope at La Silla 
Observatory (Chile).

Observations started at 09:13 UT on March 13, 7 minutes after the GRB 
trigger. We confirm that the afterglow candidate reported by Chornock et 
al. (GCN 8979) is bright in all bands.

We measure the following preliminary magnitudes at a mean time of about 10 
minutes after the burst (Vega mags):

J = 14.0 +/- 0.1
H = 13.1 +/- 0.1
K = 12.3 +/- 0.1

calibrated against 2MASS field stars. Astrometry gives RA, DEC (J2000) = 
13:13:36.21, +08:05:49.2 (+/- 0.5 arcsec). As already noted by Chornock 
et al., the afterglow is close to a bright galaxy.

These are preliminary data. Data reduction is in progress.