Search Publications
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…
Deblurring galaxy images with Tikhonov regularization on magnitude domain
Takeuchi, Tsutomu T.; Murata, Kazumi
We propose a regularization-based deblurring method that works efficiently for galaxy images. The spatial resolution of a ground-based telescope is generally limited by seeing conditions and is much worse than space-based telescopes. This circumstance has generated considerable research interest in the restoration of spatial resolution. Since imag…
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…
The first photometric investigation of the poor-thermal contact binary V749 Aurigae
Zhu, Li-Ying; Sarotsakulchai, Thawicharat; Soonthornthum, Boonrucksar +1 more
The multi-filter light curve analysis of V749 Aurigae (thereinafter V0749 Aur) is conducted for the first time. Its orbital period is improved from P = 0.409873 to 0.409890 d in this work. The photometric data from the All-Sky Automated Survey for SuperNovae (ASAS-SN) were utilized to examine the revised orbital period. Then, the phased multi-filt…
Physical properties of the molecular cloud, N4, in SS 433: Evidence for an interaction of molecular cloud with the jet from SS 433
Nakanishi, Hiroyuki; Yamamoto, Hiroaki; Imai, Hiroshi +3 more
We conducted observations and analyses of the molecular cloud, N4, which is located at ~40 pc from SS 433 and the same line of sight as that of the radio shell, in 12CO(J = 1-0), 12CO(J = 3-2), 13CO(J = 3-2), and grand-state OH emissions. N4 has a strong gradient of the integrated intensity of 12CO(J = 1…
Measurements of chromospheric Mg I emission lines of zero-age main-sequence stars
Itoh, Yoichi; Yamashita, Mai
The chromosphere is the active atmosphere in which energetic eruption events, such as flares, occur. Chromospheric activity is driven by the magnetic field generated by stellar rotation and convection. The relationship between chromospheric activity and the Rossby number, the ratio of the rotational period to the convective turnover time, has been…
Gaia DR2 and EDR3 data and evolutionary status of post-AGB stars with high radial velocities
Matsuno, Tadafumi; Aoki, Wako; Parthasarathy, Mudumba
Using the Gaia Data Release 2 (DR2) and Early Data Release 3 (EDR3) data and list of post-AGB candidates, we investigate the parallax, proper motion, and binarity for 20 post-AGB stars and candidates that have high radial velocities. From their Gaia distances, their luminosities and kinematics are derived. The evolutionary status of these stars is…
PNV J00444033+4113068: Early superhumps with 0.7 mag amplitude and non-red color
Maehara, Hiroyuki; Nogami, Daisaku; Uemura, Makoto +13 more
In the first days of WZ Sge-type dwarf nova (DN) outbursts, the 2 : 1 resonance induces a spiral arm structure in the accretion disk, which is observed as early superhumps in optical light curves. We reports on our optical observations of an eclipsing WZ Sge-type DN PNV J00444033+4113068 during its 2021 superoutburst using the 3.8 m Seimei telesco…
ANDICAM I- and J-band monitoring of bright inner Galactic late-type stars
Messineo, Maria
Time-series photometry in the I and J bands of 57 inner Galactic late-type stars, highly probable red supergiant (RSG) stars, is presented here. 38% of the sample presents significant photometric variations. The variations in the I and J bands appear to be correlated, with ΔI ∝ ΔJ × 2.2, ΔI variations ranging from 0.04-1.08 mag, and ΔJ variations …
Suzaku observations of Fe K-shell lines in the supernova remnant W 51 C and hard X-ray sources in the proximity
Fujita, Yutaka; Nobukawa, Masayoshi; Nobukawa, Kumiko K. +2 more
In this paper, we investigate the Fe K-shell lines in the supernova remnant W 51 C and hard X-ray sources in the proximity. We measure the intensities of the Fe I Kα and Fe XXV Heα lines at 6.40 and 6.68 keV, respectively, and find that the intensity of the 6.68 keV line is consistent with the background level expected from previous studies, while…