TITLE: GCN CIRCULAR NUMBER: 25638 SUBJECT: LIGO/Virgo S190901ap: Keck I LRIS spectroscopy of ZTF19abvionh DATE: 19/09/04 00:26:12 GMT FROM: Mansi M. Kasliwal at Caltech/Carnegie Kevin Burdge (Caltech), Mansi M. Kasliwal (Caltech), Daniel A. Perley (LJMU) report on behalf of the GROWTH collaboration We obtained a Keck I LRIS spectrum of ZTF19abvionh (Kool et al. GCN 25616). We see a hot, blue continuum and host galaxy lines at z=0.0985. The corresponding luminosity distance of 456 Mpc is inconsistent with the GW constraints on S190901ap (LVC et al. GCN 25614, GCN 25606) suggesting this could evolve into a young supernova. Our conclusions are broadly consistent with Rossell et al. GCN 25622.