TITLE:   GCN CIRCULAR
NUMBER:  21037
SUBJECT: GRB 170424A: LCO Observations
DATE:    17/04/25 20:23:46 GMT
FROM:    Antonino Cucchiara at UVI  <antonino.cucchiara@uvi.edu>

A. Cucchiara, D. Morris (U. of Virgin Islands), C. Guidorzi
(U. Ferrara), B. Gendre  (U. of Virgin Islands),
reports on behalf of a larger collaboration:


"On April 25.12 UT  (T_0 +14.5h) we began observing the center
of the field of LAT GRB 170424A (Omodei et al. GCN #21032)
using the Las Cumbres Observatory 1m Sutherland facility.
We covered 30% of the LAT error region and we obtained a series
of observations in R and I band for a total of 6 minutes on sky in
each filter.

We identified no optical counterpart within the center of Swift-XRT
tile #20753  (Evans et al. GCN #21034), out to a radius of ~13 arcmin,
at the following 3-sigma limits:

R > 21.2 mag
I > 20.8 mag

These magnitude are calibrated against nearby USNO-B1 sources,
and are not corrected for Galactic Extinction."




Antonino Cucchiara, PhD
Assistant Professor
Physics and Astronomy
University of the Virgin Islands

Phone: 340-693-1688
College of Science and Mathematics
#2 Brewers Bay road
St. Thomas, USVI 00802