[vsnet-grb-info 11158] GRB 111117A: TNG observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12570
SUBJECT: GRB 111117A: TNG observations
DATE:    11/11/18 11:32:21 GMT
FROM:    Andrea Melandri at INAF-OAB  <andrea.melandri at brera.inaf.it>

A. Melandri, D. Fugazza, S. Covino (INAF-OAB) and E. Palazzi (INAF- 
IASFBo)
on behalf of a larger collaboration report:

We observed the field of GRB 111117A (Mangano et al. GCN 12559) with  
the 3.6m TNG equipped with the Dolores camera. A sequence of 6x300s  
images were acquired starting on Nov 17.801 UT (i.e. ~7 hours after  
the burst event).

No obvious fading object is detected inside the refined XRT error  
circle (Melandri et al. GCN 12565), while the extended object  
previously reported by Andersen et al. (GCN 12563), Fong et al. (GCN  
12566), Cucchiara et al. (GCN 12567) and Schmidl et al. (GCN 12568) is  
clearly visible in our coadded image.

Calibrating against a set of USNO-B1 stars of the field we find R =  
23.1 +/- 0.2, consistent with the value found by Andersen et al. (GCN  
12563). We caution about the possible fading of this object, as  
reported by Fong et al. (GCN 12566), because the apparent difference  
of magnitude could be related to the different calibration system.  
Since this object is extended also in our image and it does not seem  
to vary, it is more likely the host galaxy of GRB 111117A.

We thank the TNG staff for their support, in particular Aldo Fiorenzano.