8 papers
Optical Super-orbital Modulation of SMC X-1: Disk Precession and a Revised Pulsar Mass
Masafumi Niwano, Nobuyuki Kawai, Michael Fausnaugh
The observational determination of the lower limit of neutron star masses is crucial for the physics of core-collapse supernovae. In this light, SMC X-1 is an important object beca…
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…
Optical Observations of the High Mass X-ray Binary MAXI J0709159/LY CMa
Megumi Shidatsu, Nobuyuki Kawai, Hiroyuki Maehara +12
We report on the optical spectroscopic monitoring of the X-ray transient MAXI J0709159 (identified as the Be star LY CMa) performed for about 1.5 months after the X-ray detectio…
UNIONS: The Ultraviolet Near-Infrared Optical Northern Survey
Stephen Gwyn, Alan W. McConnachie, Jean-Charles Cuillandre +86
The Ultraviolet Near-Infrared Optical Northern Survey (UNIONS) is a "collaboration of collaborations" that is using the Canada-France-Hawai'i Telescope, the Pan-STARRS telescopes,…
The possible long-term periodic variability of the extremely luminous quasar WISE J090924.01+000211.1
Takashi Horiuchi, Yoshiki Toba, Toru Misawa +11
The extremely luminous infrared galaxy (ELIRG), WISE J090924.01+000211.1 (hereafter; WISE J0909+0002, ) is an extraordinary object with a quasar aspect. This study performs…