[vsnet-grb-info 8845] GRB 100117A: Optical object inside the revised XRT error circle

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10343
SUBJECT: GRB 100117A: Optical object inside the revised XRT error circle
DATE:    10/01/18 16:23:10 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann at tls-tautenburg.de>

D. Alexander Kann (TLS Tautenburg), D. Malesani (DARK/NBI), D. Xu (WIS, 
DARK/NBI) report on behalf of a larger collaboration:

Using the improved XRT position (B. Sbarufatti et al. GCN 10342) for the 
Swift short/hard GRB 100117A (M. de Pasquale et al., GCN 10336), we find 
that the afterglow candidate reported from NOT observations (D. Xu et al., 
GCN 10337), which is probably identical to source "S1" from S. B. Cenko et 
al. (GCN 10339), lies outside the error circle. We therefore consider it 
unlikely that this object is related to the GRB, also considering the lack 
of pronounced variability (S. B. Cenko et al. GCN 10339).

Of the four sources reported by S. B. Cenko et al. (GCN 10339) and 
confirmed by R. Chornock et al. (GCN 10340) and A. Cucchiara et al. (GCN 
10341), only source "S3" still lies within the new XRT error circle. 
Source S3, which is extended according to the above reports, may be the 
host galaxy of GRB 100117A, although lack of variability does not allow a 
conclusive statement.

An additional image epoch to perform image subtraction is encouraged.

This message may be cited.