[vsnet-grb-info 11011] GRB 111008A, GROND observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12428
SUBJECT: GRB 111008A, GROND observations
DATE:    11/10/09 06:31:49 GMT
FROM:    Sylvio Klose at TLS Tautenburg  <klose at tls-tautenburg.de>

M. Nardini (Milano Bicocca), S. Klose (TLS Tautenburg), J. Greiner (MPE 
Garching), and P. Afonso (MPE/American River College) report on behalf of 
the GROND team:

We observed the field of GRB 111008A (Saxton et al., GCN #12423) 
simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 
405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory 
(Chile).

Observations started at 4:30 UT on October 08, 6.3 hours after the GRB 
trigger.

We detect a point source within the 1.7 arcsec enhanced Swift-XRT error 
circle (Beardmore et al., GCN #12425) at coordinates RA, DEC (J2000) = 
04:01:48.25, -32:42:33.2 (+/-0.5"), confirming the observations from 
Gemini (Levan et al., GCN 12426).

Preliminary magnitudes at a meantime of 5:15 UT are (in the AB system):

g' > 24.0,
r' = 22.6 +/- 0.1,
i' = 20.9 +/- 0.1,
z' = 19.9 +/- 0.1,

indicating a cosmological g-band dropout.

Data are calibrated against GROND zeropoints. Observations are ongoing.