Search Publications
Second data release of the Hyper Suprime-Cam Subaru Strategic Program
Ono, Yoshiaki; Ouchi, Masami; Harikane, Yuichi +62 more
This paper presents the second data release of the Hyper Suprime-Cam Subaru Strategic Program, a wide-field optical imaging survey using the 8.2 m Subaru Telescope. The release includes data from 174 nights of observation through 2018 January. The Wide layer data cover about 300 deg^2 in all five broad-band filters (grizy) to the nominal survey ex…
Detections of [O III] 88 µm in two quasars in the reionization epoch
Inoue, Akio K.; Hashimoto, Takuya; Tamura, Yoichi +3 more
We report on detections with the Atacama Large Millimeter/sub-millimeter Array of the far-infrared [O III] 88 µm line and the underlying dust continuum in two quasars in the reionization epoch, J205406.48-000514.8 (hereafter J2054-0005) at z = 6.0391 ± 0.0002 and J231038.88+185519.7 (hereafter J2310+1855) at z = 6.0035 ± 0.0007. The [O III] …
Three Z Camelopardalis-type dwarf novae exhibiting IW Andromedae-type phenomenon
Kato, Taichi
I found that V507 Cyg, IM Eri, and FY Vul are Z Cam-type dwarf novae and they showed sequences of standstill terminated by brightening, in contrast to fading as ordinary Z Cam stars do, followed by damping oscillation. These sequences are characteristic to IW And-type objects (also known as anomalous Z Cam stars). New additions to the IW And-type …
The W-subtype active contact binary PZ UMa with a possible more massive tertiary component
Soonthornthum, Boonrucksar; Zhou, Xiao
Two sets of multiple-color (B, V, RC, IC) light curves of PZ UMa were observed independently with the 2.4 m telescope at the Thai National Observatory and the 1 m telescope at Yunnan Observatories. The light curves were analyzed with the Wilson-Devinney program and the two sets of light curves produced consistent results, whi…
Near-infrared imaging polarimetry toward M 17 SWex
Kusune, Takayoshi; Nakamura, Fumitaka; Tamura, Motohide +7 more
We conducted near-infrared (JHK_s) imaging polarimetry toward the infrared dark cloud (IRDC) M 17 SWex, including almost all of the IRDC filaments as well as its outskirts, with the polarimeter SIRPOL on the IRSF 1.4 m telescope. We revealed the magnetic fields of M 17 SWex with our polarization-detected sources that were selected by some criteria…
Photospheric nitrogen abundances and carbon 12C/13C ratios of red giant stars
Sato, Bun'ei; Omiya, Masashi; Harakawa, Hiroki +1 more
Nitrogen abundances and carbon isotope ratios (12C/13C) in the atmospheres of red giants are known to be influenced by dredge-up of H-burning products, and serve as useful probes to study the nature of evolution-induced envelope mixing. We determined the [N/Fe] and 12C/13C ratios for 239 late-G/early-K g…
Searching for hot subdwarf stars from the LAMOST Spectra. II. Pure spectroscopic identification method for hot subdwarfs
Zhao, Gang; Németh, Péter; Zhao, Jingkun +2 more
Employing a new machine-learning method, named the hierarchical extreme learning machine (HELM) algorithm, we identified 56 hot subdwarf stars in the first data release (DR1) of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) survey. The atmospheric parameters of the stars are obtained by fitting the profiles of hydrogen (H)…
YZ Phoenicis: a very short period K-type contact binary with variation of the O'Connell effect and orbital period change
Li, Lin-Jia; Qian, Sheng-Bang; Zhang, Jia +7 more
YZ Phe is a very short-period contact binary (Sp. = K2 V) with an orbital period of 0.2347 d near the short period limit (0.22 d). We present the complete light curves which photometric data were obtained from the 60 cm telescope of PROMPT-8 at CTIO in Chile during 2016 June to October and 2017 August. The photometric solutions were determined by …
NSV 1440: first WZ Sge-type object in AM CVn stars and candidates
Nogami, Daisaku; Myers, Gordon; Monard, Berto +5 more
In 2015 and 2017, the AM CVn candidate NSV 1440 showed superoutbursts that had the characteristic features of WZ Sge-type dwarf novae (DNe). By analogy with hydrogen-rich cataclysmic variables (CVs), we can interpret these outbursts as "double superoutbursts" which are composed of a first superoutburst with early superhumps and a second superoutbu…
Annual parallax measurements of a semi-regular variable star SV Pegasus with VERA
Honma, Mareki; Nakagawa, Akiharu; Nagayama, Takahiro +6 more
Many studies have shown that there are clear sequences in the period-luminosity relationship (PLR) for Mira variables and semi-regular variables (SRVs) in the Large Magellanic Cloud (LMC). To investigate the PLR for SRVs in our galaxy, we examined the annual parallax measurement and conducted K'-band photometric monitoring of an SRV star SV Pegasu…