TITLE: GCN CIRCULAR NUMBER: 24230 SUBJECT: LIGO/Virgo S190425z: J-GEM spectroscopic observations of AT2019ebq/PS19qp with Subaru/FOCAS DATE: 19/04/26 15:50:38 GMT FROM: Tomoki Morokuma at U of Tokyo Morokuma, T. (U. of Tokyo), Ohta, K. (Kyoto U.), Yoshida, M., Aoki, K. (NAOJ/Subaru), Tanaka, M. (Tohoku U.), Sasada, M., Nakaoka, T., Akitaya, H., Kawabata, K. S. (Hiroshima U.), Itoh, R. (Bisei Astronomical Observatory), Utsumi, Y. (Stanford U./SLAC), on behalf of J-GEM collaboration We performed spectroscopic observations of AT2019ebq/PS19qp (Smith et al. 2019, GCN, 24210), a possible counterpart to the gravitational wave event S190425z, with the Faint Object Camera and Spectrograph (FOCAS; Kashikawa et al. 2002, PASJ, 54, 819) on the 8.2-m Subaru Telescope. We started our observations at UT 2019-04-26 13:43, about 1.2 days after the event. We took a red part of optical spectrum, covering from 7,000 A to 10,000 A. At the redshift of z=0.037 (Nicholl et al. 2019, GCN, 24217; Jonker et al. 2019, GCN, 24221), the spectrum shows a broad P-Cygni profile with an absorption minimum around 8200 A and an emission peak around 8600 A. There is also another absorption feature around 7500 A. These features can be attributed to the Ca II IR triplet and the O I 7774, respectively. Therefore, this source is likely to be a reddened supernova and unlikely to be associated with the gravitational wave event.