TITLE: GCN CIRCULAR NUMBER: 21692 SUBJECT: LIGO/Virgo G297595: Gemini and VLT observations by GLGW Hunters DATE: 17/08/25 14:18:20 GMT FROM: Graham P Smith at U of Birmingham G. P. Smith (Birmingham), M. Jauzac (Durham), M. Bianconi (Birmingham), J. Richard (Lyon), C. P. L. Berry (Birmingham), W. M. Farr (Birmingham), R. Massey (Durham), A. Robertson (Durham), K. Sharon (Michigan), A. Vecchio (Birmingham), J. Veitch (Glasgow) The Gravitationally-lensed Gravitational Wave Hunters collaboration report observations of strong-lensing galaxy clusters located within the sky localisation of the LIGO/Virgo trigger G297595 (LVC GCN Circ. 21474). Following Smith et al. (arXiv:1707.03412) we searched the initial (August 14th) and updated (August 16th) skymaps for strong-lensing galaxy clusters that lie within the 90% credible sky localisation. Abell 3084 was the closest strong-lensing galaxy cluster to the peak probability in the initial skymap. We observed this cluster through the i-band filter with GMOS on Gemini-South on the nights of August 14, 16, 17, 20, 21, and with MUSE on VLT on the nights of August 16, and 18. GMOS spans a 5.5x5.5 arcminute field of view, and MUSE spans a 1x1 arcminute field of view with a wavelength range of 4650-9300 Angstroms. SMACSJ0304.3-4401 was the closest strong-lensing galaxy cluster to the peak probability in the updated skymap. We observed this cluster through the i-band filter with GMOS on Gemini-South on the nights of August 17 and 20. Analysis of these data is ongoing. Colleagues with complementary data are welcome to contact us with a view to collaboration. We thank the staff at ESO and Gemini for their outstanding support of our observing programmes.