TITLE:   GCN CIRCULAR
NUMBER:  26147
SUBJECT: GRB 191031D: Gemini optical upper limit
DATE:    19/11/02 19:25:43 GMT
FROM:    Eleonora Troja at NASA/GSFC/UMD  <eleonora@umd.edu>

S.Dichiara (UMD, NASA-GSFC) and E. Troja (UMD, NASA-GSFC) report on behalf
of a larger collaboration:

We observed the field of the short duration GRB 191031D (Fermi GBM Team,
GCN Circ. 26111; D'Elia et al., GCN Circ. 26112) with the Gemini North
8-meter telescope located on Mauna Kea, beginning on 2019-11-02  04:43:08
UT, approximately 1.3 d post-burst. We obtained a series of 6x120s r-band
images using the Gemini Multi-Object Spectrograph (GMOS).

No credible counterpart is detected within the enhanced X-ray position
(Osborne el al., GCN 26117) down to r > 25 AB mag, not corrected for
Galactic extinction.

We thank S. Stewart and the Gemini North staff for executing these
observations.