TITLE:   GCN CIRCULAR
NUMBER:  20413
SUBJECT: LIGO/Virgo G268556: ATLAS17aeu position is consistent with GRB170105A
DATE:    17/01/10 06:15:41 GMT
FROM:    Varun Bhalerao at IUCAA  <varunb@iucaa.in>

Varun Bhalerao (IUCAA), Sujay Mate (IUCAA), Dipankar Bhattacharya (IUCAA), Sukanta Bose (IUCAA), Gulab Chand Dewangan (IUCAA), Ranjeev Misra (IUCAA), Sanjit Mitra (IUCAA), A R Rao (TIFR), Tarun Souradeep (IUCAA), Santosh Vadawale (PRL), on behalf of the Astrosat CZTI team report:

Bhalerao et al. (GCN Circ. 20412) have used AstroSat CZTI to infer that GRB170105A is a long GRB, and have localised it to a  ~550 square degree region (1-sigma). This region includes 3.9% probability of containing the LIGO trigger G268556, based on the revised LALInference sky map (Greco et al,  20385). The overlap with the IPN triangulation (Svikin et al., GCN Circ. 20406) is about 50 square degrees.

The position of ATLAS17aeu (Tonry et al., GCN Circ. 20382) is marginally outside the AstroSat CZTI error region, consistent at better than 1.1 sigma. This further indicates that ATLAS17aeu is the afterglow of GRB170105A (Kasliwal et al., GCN Circ. 20393).