[vsnet-grb-info 21177] GRB 180925A: VLT optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23276
SUBJECT: GRB 180925A: VLT optical observations
DATE:    18/09/27 19:52:07 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at dark-cosmology.dk>

D. B. Malesani (DAWN/NBI and DARK/NBI), P. Schady (Univ. Bath), C. C. 
Thoene (HETH/IAA-CSIC), D. A. Kann (HETH/IAA-CSIC), and N. R. Tanvir 
(Univ. Leicester) report on behalf of the Stargate collaboration:

We observed the optical counterpart of GRB 180925A (Gropp et al., GCN 
23268; Emery & Gropp, GCN 23274) using the ESO VLT UT2 (Kueyen) equipped 
with the X-shooter instrument. A 60-seconds image in the SDSS r filter 
was taken with the acquisition camera, at approximate time 2018 
September 26.17 UT (0.56 days after the GRB).

At a location consistent with that of the UVOT afterglow (Emery & Gropp, 
GCN 23274), a faint source is marginally visible. Forced photometry, 
calibrated against nearby USNO-B1 stars, yields R = 22.9 +- 0.4 (Vega).

No further observations are planned.

We acknowledge support from the ESO staff at Paranal, in particular Joe 
Anderson and Jorge Lillo-Box.