Further Spectroscopic Follow-up Observations of RS Ophiuchi with Seimei Telescope

ATel #14858; Kenta Taguchi (Kyoto University), Hiroyuki Maehara (National Astronomical Observatory of Japan), Keisuke Isogai, Yusuke Tampo, Junpei Ito (Kyoto University)
on 13 Aug 2021; 06:56 UT
Credential Certification: Hiroyuki Maehara (hiroyuki.maehara@nao.ac.jp)

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We report our optical spectroscopy of the 2021 outburst of the recurrent nova RS Ophiuchi (cvnet-outburst 753, vsnet-alert 26131, CBET 5013, 5015, ATels #14834, #14838, #14840, #14844, #14845, #14846, #14848, #14849, #14850, #14851, #14852, #14855, #14857), additional to the one reported in ATel #14838. We took spectra of RS Ophiuchi from 2021-08-10.498 to 2021-08-10.502 and from 2021-08-11.530 to 2021-08-11.534 simultaneously with the NICER X-ray observation (ATel #14850) by using the fiber-fed integral field spectrograph (KOOLS-IFU; Matsubayashi et al. 2019) mounted on the 3.8-m Seimei telescope (Kurita et al. 2020) at Okayama Observatory of Kyoto University.

As reported in ATel #14852, we confirmed the velocity of the P Cyg absorption component in the Hβ line, measured from the emission peak, had significantly increased between August 9th and 10th: ∼ −2600 km/s on 2021-08-09.44 (ATel #14838), ∼ −4200 km/s on 2021-08-10.50, and ∼ −4300 km/s on 2021-08-11.53. The FWZI of Hα had also increased between August 9th and 10th: ∼ 3400 km/s on 2021-08-09.44, ∼ 7300 km/s on 2021-08-10.50, and ∼ 7800 km/s on 2021-08-11.53. Although the continuum flux had decreased between August 9th and 10th, the Balmer and O I line fluxes had increased. Also, the He I lines (e.g., 5876 Å) became more prominent.

Spectra of RS Oph observed with the Seimei/KOOLS-IFU