[vsnet-grb-info 20878] GRB 180720B: LCO Haleakala possible bright optical candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22976
SUBJECT: GRB 180720B: LCO Haleakala possible bright optical candidate
DATE:    18/07/20 15:30:47 GMT
FROM:    Renato Martone at Universita' di Ferrara  <mrtrnt at unife.it>

R. Martone, C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:

The LCO 2-m unit at Haleakala Observatory (Hawaii) began observing Swift GRB180720B (Siegel et al. GCN 22973)  on July 20, 14:33:34 UT (11.8 minutes after the GRB trigger time) with the SDSS i' filter. On the border of the Swift-XRT error circle, we detect a 13-mag uncatalogued object at the following position:

RA(J2000)= +00:02:06.87
DEC(J2000)= -02:55:05.2

with an error radius of ~1”  as calibrated against nearby SDSS stars.