TITLE:   GCN CIRCULAR
NUMBER:  24324
SUBJECT: LIGO/Virgo S190425z: 1.5m OSN and 10.4m imaging of the UVOT source field
DATE:    19/04/28 07:28:53 GMT
FROM:    Alberto J. Castro-Tirado at IAA-CSIC  <ajct@iaa.es>

Y.-D. Hu, A. J. Castro-Tirado, X.-Y. Li, A. Ayala, E. Fernandez-Garcia
and F. J. Aceituno (IAA-CSIC), R. Sanchez-Ramirez (INAF-IAPS), M. D.
Caballero-Garcia (ASU-CAS) and N. Castro-Rodriguez (GRANTECAN, IAC,
ULL), on behalf of a larger collaboration, report:

Following the detection of Swift/UVOT of a transient (Breeveld et al.,
GCN 24296) within the error area of the GW event S190425z (LIGO
Scientific Collaboration and the Virgo Collaboration, GCN  24168), we
observed the target with the 1.5m telescope at the  Observatorio de
Sierra Nevada (Spain) in the R-band, starting on Apr  27, 03:44 UT. The
co-add of 3 frames (600s each) revealed no object down to 22.3 mag at
the position of the UVOT source. Deeper images were taken at the 10.4m
GTC telescope equipped with OSIRIS in La Palma (Spain) starting on Apr
27, 05:11 UT. The potential host galaxy reported by Palmese et al., GCN
24312) is detected in our 60s frames with r = 22.8+-0.2.


We acknowledge the excellent support from the GTC staff.