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GCN Circular 24230

Subject
LIGO/Virgo S190425z: J-GEM spectroscopic observations of AT2019ebq/PS19qp with Subaru/FOCAS
Date
2019-04-26T15:50:38Z (5 years ago)
From
Tomoki Morokuma at U of Tokyo <tmorokuma@ioa.s.u-tokyo.ac.jp>
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.
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