[vsnet-grb-info 23900] GRB 19011A: Optical Afterglow Detection with LCO

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25999
SUBJECT: GRB 19011A: Optical Afterglow Detection with LCO
DATE:    19/10/11 13:52:55 GMT
FROM:    Robert Strausbaugh at U. of the Virgin Islands  <robert.strausbaugh at uvi.edu>

R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration:

We observed Fermi GRB 191011A (Fermi GBM Team at MSFC/Fermi-GBM, GCN 25987) with
the LCO 1-m Sinistro instrument at the Cerro Tololo site on October 11, from 04:54 to 05:18 UT
(corresponding to 0.13 to 0.4 hours from the GRB trigger time)
with the Bessel I filter.

We performed a series of 5x120s exposures.  While we do not detect a source in individual frames, we do detect a source in co-added frames that is not present in either USNO-B1.0 or 2MASS surveys that is consistent with the optical afterglow location (Palmer et al., GCN 25988) with the following magnitude:

I = 18.81 +/- 0.13

This flux is calibrated against several USNO-B1.0 objects near the GRB location but is not corrected for Galactic Extinction.

These observations were possible thanks to the USVI NASA-EPSCoR
Research Infrastructure Development (RID) grant NNX16AL44A.