Search Publications
Third data release of the Hyper Suprime-Cam Subaru Strategic Program
Ono, Yoshiaki; Ouchi, Masami; Harikane, Yuichi +64 more
This paper presents the third data release of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP), a wide-field multi-band imaging survey with the Subaru 8.2 m telescope. HSC-SSP has three survey layers (Wide, Deep, and UltraDeep) with different area coverages and depths, designed to address a wide array of astrophysical questions. This third…
The three-year shear catalog of the Subaru Hyper Suprime-Cam SSP Survey
Strauss, Michael A.; Takita, Satoshi; Miyatake, Hironao +15 more
We present the galaxy shear catalog that will be used for the three-year cosmological weak gravitational lensing analyses using data from the Wide layer of the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP) Survey. The galaxy shapes are measured from the i-band imaging data acquired from 2014 to 2019 and calibrated with image simulations t…
Fast optical flares from M dwarfs detected by a one-second-cadence survey with Tomo-e Gozen
Kobayashi, Naoto; Takita, Satoshi; Arimatsu, Ko +18 more
We report on a one-second-cadence wide-field survey for M-dwarf flares using the Tomo-e Gozen camera mounted on the Kiso Schmidt telescope. We detect 22 flares from M3-M5 dwarfs with a rise time of 5 s ≲ trise ≲ 100 s and an amplitude of 0.5 ≲ ΔF/F⋆ ≲ 20. The flare light-curves mostly show steeper rises and shallower decays t…
A super-Earth orbiting near the inner edge of the habitable zone around the M4.5 dwarf Ross 508
Henning, Thomas; Nakagawa, Takao; Currie, Thayne +46 more
We report the near-infrared radial velocity (RV) discovery of a super-Earth planet on a 10.77 d orbit around the M4.5 dwarf Ross 508 (Jmag = 9.1). Using precision RVs from the Subaru Telescope IRD (InfraRed Doppler) instrument, we derive a semi-amplitude of $3.92^{+0.60}_{-0.58}\:\mbox{m}\:{\mbox{s}^{-1}}$, corresponding to a planet wit…
TOI-2285b: A 1.7 Earth-radius planet near the habitable zone around a nearby M dwarf
Bieryla, Allyson; Latham, David W.; Quinn, Samuel N. +60 more
We report the discovery of TOI-2285b, a sub-Neptune-sized planet transiting a nearby (42 pc) M dwarf with a period of 27.3 d. We identified the transit signal from the Transiting Exoplanet Survey Satellite photometric data, which we confirmed with ground-based photometric observations using the multiband imagers MuSCAT2 and MuSCAT3. Combining thes…
Starspots, chromospheric emission lines, and flares of zero-age main-sequence stars
Itoh, Yoichi; Oasa, Yumiko; Yamashita, Mai
Zero-age main-sequence (ZAMS) stars are considered to have enormous starspots and show strong chromospheric emission lines because of their strong surface magnetic field. We discuss the dynamo activities of ZAMS stars with respect to their periodic light variation caused by a starspot and with respect to the strength of the chromospheric emission …
Regular radial velocity variations in nine G- and K-type giant stars: Eight planets and one planet candidate
Izumiura, Hideyuki; Sato, Bun'ei; Yoshida, Michitoshi +9 more
We report the detection of radial velocity (RV) variations in nine evolved G- and K-type giant stars. The observations were conducted at Okayama Astrophysical Observatory. Planets or planet candidates can best explain these regular variations. However, a coincidence of near 280 d variability among five of them prevents us from fully ruling out ste…
Video observations of tiny near-Earth objects with Tomo-e Gozen
Kobayashi, Naoto; Takita, Satoshi; Usui, Fumihiko +20 more
We report the results of video observations of tiny (diameter less than 100 m) near-Earth objects (NEOs) with Tomo-e Gozen on the Kiso 105 cm Schmidt telescope. The rotational period of a tiny asteroid reflects its dynamical history and physical properties since smaller objects are sensitive to the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effe…
Deep near-infrared imaging observation of the faint X-ray point sources constituting the Galactic bulge X-ray emission
Gandhi, Poshak; Tsujimoto, Masahiro; Ebisawa, Ken +1 more
The presence of the apparently extended hard (2-10 keV) X-ray emission along the Galactic plane has been known since the early 1980s. With a deep X-ray exposure using the Chandra X-ray Observatory of a slightly off-plane region in the Galactic bulge, most of the extended emission was resolved into faint discrete X-ray sources in the Fe K band (Rev…
Detection of highly correlated optical and X-ray variations in SS Cygni with Tomo-e Gozen and NICER
Enoto, Teruaki; Takita, Satoshi; Yamada, Shinya +8 more
We report on simultaneous optical and X-ray observations of the dwarf nova SS Cyg with Tomo-e Gozen/1.05 m Kiso Schmidt and Neutron star Interior Composition ExploreR (NICER)/International Space Station (ISS). A total of four observations were carried out in the quiescent state and highly correlated light variations between the two wavelengths wer…