8 papers
Discovery of an Eccentric Hot Super-Jupiter Leaving the Transiting Geometry of the Early-A-type star TOI-1355
Noriharu Watanabe, Norio Narita, Akihiko Fukui +20
Hot Jupiters orbiting hot stars ( K) are suggested to have experienced high-eccentricity migration, often evidenced by the tendency for misaligned orbits, de…
Spectral and photometric variability of SS 433 observed with XRISM and simultaneous optical and near-infrared telescopes
Yusuke Sakai, Shinya Yamada, Yuta Okada +36
We present results from coordinated multiwavelength observations of the SS 433, obtained with XRISM, optical telescopes, and near-infrared camera during 2024 April and 2025 March.…
Multiband Optical Photometric and Spectroscopic Monitoring of the 2024 Flare Event in Transition Blazar OP313
TianFang Zhang, Mitsuru Kokubo, Mamoru Doi +19
Blazars are active galactic nuclei known for their extreme variability, offering unique opportunities to study jet physics and high-energy emission mechanisms. In 2024, the Flat Sp…
XRISM reveals a variable, multi-phase outflow-inflow structure during the X-ray obscured 2024 outburst of the black hole transient V4641 Sgr
Maxime Parra, Megumi Shidatsu, Ryota Tomaru +23
We report the results of a simultaneous X-ray and optical spectroscopy campaign on the Galactic black hole X-ray binary V4641 Sgr, carried out with XRISM and the Seimei telescope d…
Spectral evolution of the narrow emission line components in optical during the 2022 nova eruption of U Scorpii
Katsuki Muraoka, Naoto Kojiguchi, Junpei Ito +20
There remains debate over whether the accretion disk survives or is entirely disrupted after the nova eruption. In our previous paper, Muraoka et al. (2024, PASJ, 76, 293) have pho…
SN 2021foa: the bridge between SN IIn and Ibn
Anjasha Gangopadhyay, Naveen Dukiya, Takashi J Moriya +26
We present the long-term photometric and spectroscopic analysis of a transitioning SN~IIn/Ibn from 10.8 d to 150.7 d post -band maximum. SN~2021foa shows prominent He {\sc i}…