[vsnet-grb-info 23697] GRB 190919B: LCO Optical Afterglow Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25796
SUBJECT: GRB 190919B: LCO Optical Afterglow Detection
DATE:    19/09/21 02:24:34 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 190919B (Mereghetti, GCN 25788) with
the LCO 1-m Sinistro instrument on September 20, from 17:58 to 19:10 UT
(corresponding to 18.27 to 19.47 hours from the GRB trigger time)
with the SDSS i’ and r’ filters.

We performed a series of 28x30s exposures in each band. We do not detect the source in individual frames; however we detect a source in stacked images (at least 5 stacked images) that is not present in USNO-B1.0 or 2MASS surveys with
the following  magnitudes:


i = 20.60 +/- 0.14

r = 21.48 +/- 0.18

This flux measurement may be partially contaminated by the host galaxy, and it is calibrated against several USNO-B1.0 objects near the GRB location but is not corrected for Galactic Extinction.

Analysis is ongoing to determine if the source is fading over the course of the observations, and therefore likely the GRB afterglow.

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