D. A. Kann, M. Blazek (both HETH/IAA-CSIC), A. de Ugarte Postigo
(HETH/IAA-CSIC, DARK/NBI), C. C. Thoene, K. Bensch, J. F. Agui (all
HETH/IAA-CSIC), and A. Sota (IAA-CSIC) report:
We observed the field of GRB 190926A (Melandri et al. GCN #25848) with
the 1.5m OSN telescope, at Sierra Nevada Observatory (Granada, Spain).
The observation is centered 0.7321 days after the GRB and consisted of
41 x 180 s exposures in the Ic band for a total exposure time of 7380 s.
No new object is detected within the refined XRT error circle (Goad et
al. GCN #25850) down to a 3-sigma limit of Ic(AB) = 23.6 mag, as
compared to stars of the PanSTARRS catalog. This is in agreement with
other non-detections (Lipunov et al., GCN #25849, Zheng & Filippenko,
GCN # 25852, Oates & Melandri, GCN #25853, Adachi et al., GCN #25854);
and the very high-significance detection of excess hydrogen column
density in the XRT observations (Sbarufatti et al., GCN #25851)
indicates this is a dark GRB, and less likely a high-redshift one.