TITLE: GCN CIRCULAR NUMBER: 25454 SUBJECT: LIGO/Virgo S190814bv: WHT spectroscopy of the host of AT2019npv DATE: 19/08/23 11:00:53 GMT FROM: Kate Maguire at Trinity College Dublin P. Jonker (SRON/Radboud Univ), K. Maguire (TCD), M. Fraser (UCD), M.A.P. Torres (IAC/ULL/SRON), A. J. Levan (Radboud Univ), A. Shlentsova (Radboud Univ) report on behalf of the GW@WHT collaboration: We obtained spectroscopy of the host galaxy of AT2019npv (DG19wxnjc) discovered in DECam images within the LIGO/Virgo S190814bv sky localisation (GCN 25333). It was first reported by Goldstein et al. (GCN 25393) at magnitude 20.6 in the z band on MJD 58713.34 with a photo-z measurement placing it within the 95% confidence region of the LIGO/Virgo distance. The transient was confirmed in Herner et al. (GCN 25398). Two spectra of the host were obtained on 2019-08-22 using the ACAM instrument mounted on the William Herschel Telescope located at the Roque de Los Muchachos Observatory, La Palma, Spain. The spectra both show weak emission consistent with Halpha at a redshift of 0.056 (250 Mpc), confirming its location spectroscopically within the most up-to-date distance range based on the GW signal of S190814bv of 267 +- 52 Mpc. The emission feature appears extended in the 2D spectra.