[vsnet-grb-info 13321] GRB 130514B: GROND observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14657
SUBJECT: GRB 130514B: GROND observations
DATE:    13/05/15 10:58:01 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann at tls-tautenburg.de>

S. Schmidl, D. A. Kann (both TLS Tautenburg) and J. Greiner (MPE Garching)
report on behalf of the GROND team:

We observed the field GRB 130514B (INTEGRAL trigger 6843; Mereghetti et
al., GCN 14638) simultaneously in g'r'i'z'JHKs 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 in late twilight at 23:11:33.7 UT on May 14th, 9.75
hours after the IBAS trigger. They were performed at an average seeing of
1".6 and at an average airmass of 1.0.

Inside the 1".8 refined XRT error circle (Zhang et al., GCN 14561), we do 
not detect any sources. Based on an observation with 1500 s integration
time in g'r'i'z' and 1200 s integration time in JHK, centered at 0.42572
days after the trigger, we estimate preliminary 3-sigma upper limits (all
in AB system) of

g' > 24.7,
r' > 24.4,
J  > 21.0,
H  > 20.7 and
K  > 20.0.

Optically, this GRB is again very faint, similar to GRB 130513A (Schmidl
et al., GCN 14639). Galactic extinction is negligible. The XRT spectrum
shows strong absorption (Zhang et al., GCN 14561), and this is probably
dark GRB.

Given magnitudes are calibrated against GROND zero points (g'r'i'z') as
well as 2MASS field stars (JHK) and are not corrected for the expected
Galactic foreground extinction corresponding to a reddening of
E_(B-V)=0.03 mag in the direction of the burst (Schlegel et al. 1998).