[vsnet-grb-info 20620] GRB 180512A: LBT optical detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22718
SUBJECT: GRB 180512A: LBT optical detection
DATE:    18/05/13 13:13:01 GMT
FROM:    Andrea Rossi at INAF  <a.rossi at iasfbo.inaf.it>

A. Rossi and E. Palazzi (INAF-OAS) report on behalf of the CIBO 
colaboration:

We  observed the field of GRB180512A (Swift trigger 832119; Deich et 
al., GCN #22710) simultaneously in r' and z' bands with the LBC imager 
mounted on LBT (Mt Graham, AZ, USA). Observations started at 04:05 UT on 
2018-05-13, 6 hrs after the GRB trigger and finished at 04:27 UT and 
allowed us to obtain 20min of exposure in each band.

Image inspection reveals a faint source within the Swift/XRT enhanced 
error circle (Evans et al., GCN 22715) with coordinates:
RA(J2000) = 13:27:45.130
Dec(J2000)= +21:24:13.39
with an uncertainty of 0.2" in each coordinate.

The source is detected only r'-band and has magnitude r' = 25.0 mag 
+-0.3 (AB), calibrated against r'-band SDSS field stars. No statement 
about the variability can be made at this point. Further observations 
are planned.

No correction for the expected Galactic foreground extinction
corresponding to a reddening of E_(B-V)=0.02 mag in the direction of the 
burst (Schlafly & Finkbeiner 2011) has been applied.

We acknowledge the excellent support from the LBT-INAF staff, 
particularly F. Cusano and A. Gargiulo in obtaining these observations.