Search Publications
LAMOST J011939.222-012150.45: The most barium-enhanced CEMP-s turnoff star
Zhao, Gang; Li, Haining; Matsuno, Tadafumi +2 more
We have performed chemical abundance analyses for a newly discovered metal-poor turn-off star (Teff = 6276 K, log g = 3.93, [Fe/H] = -2.93), LAMOST J011939.222-012150.45, based on high-resolution and high signal-to-noise ratio spectra in both optical and near-UV obtained by Subaru. Abundances have been derived for 20 elements, including…
The interplay between active galactic nuclei and star formation activities of type 1 active galactic nuclei probed by polycyclic aromatic hydrocarbon 3.3 µm emission feature with AKARI
Nakagawa, Takao; Oyabu, Shinki; Ohyama, Youichi +11 more
We investigate the connection between active galactic nucleus (AGN) and star formation activities of AGN host galaxies by studying the 3.3 µm polycyclic aromatic hydrocarbon (PAH) emission feature of 79 type 1 AGNs using the AKARI space telescope. Utilizing the slitless spectroscopic capability of the AKARI Infrared Camera, we obtained the s…
Membership and fundamental parameters of the intermediate-age open clusters NGC 2281 and NGC 2539 based on Gaia-DR2
Gao, Xin-Hua
This paper presents an investigation on the two intermediate-age open clusters NGC 2281 and NGC 2539 based on Gaia Data Release 2 (Gaia-DR2). A combined machine-learning method is used to identify likely cluster members of the two clusters, taking into account the astrometric and photometric data of Gaia-DR2. It is found that NGC 2281 and NGC 2539…
AKARI mission program: Excavating Mass Loss History in extended dust shells of Evolved Stars (MLHES). I. Far-IR photometry†
Yamamura, Issei; Takita, Satoshi; Izumiura, Hideyuki +3 more
We performed a far-IR imaging survey of the circumstellar dust shells of 144 evolved stars as a mission program of the AKARI infrared astronomical satellite using the Far-Infrared Surveyor (FIS) instrument. With this survey, we deliver far-IR surface brightness distributions of roughly 10' × 40' or 10' × 20' areas of the sky around the target evol…
Galactic foreground of gamma-ray bursts from AKARI Far-Infrared Surveyor
Doi, Yasuo; Onishi, Toshikazu; Zahorecz, Sarolta +8 more
We demonstrate the use of the AKARI FIS All-Sky Survey maps in the study of extragalactic objects. A quick but reliable estimate of the Galactic foreground is essential for extragalactic research in general. We explored the galactic foreground and calculated hydrogen column densities using AKARI FIS and other recent all-sky survey data, and compar…
An enigmatic hump around 30 keV in Suzaku spectra of Aquila X-1 in the hard state
Makishima, Kazuo; Tamagawa, Toru; Nakano, Toshio +4 more
The typical accreting neutron star, Aquila X-1, was observed with Suzaku seven times in the decay phase of an outburst in 2007 September-October. Among them, the second to the fourth observations were performed 10 to 22 days after the outburst peak, when the source was in the hard state with a luminosity of 2 × 1036 erg s-1. …
AKARI and IRAS: From beam corrections to SEDs
Pearson, Chris; Clements, David L.; Wang, Lingyu +6 more
There is significant scientific value to be gained from combining AKARI fluxes with data at other far-infrared (IR) wavelengths from the Infrared Astronomical Satellite (IRAS) and Herschel missions. To be able to do this we must ensure that there are no systematic differences between the data sets that need to be corrected before the fluxes are co…
Suzaku observation of Jupiter's X-rays around solar maximum
Miyoshi, Yoshizumi; Ezoe, Yuichiro; Ishikawa, Kumi +6 more
We report on results of imaging and spectral studies of X-ray emission from Jupiter observed by Suzaku. In 2006, Suzaku found diffuse X-ray emission in 1-5 keV associated with Jovian inner radiation belts. It has been suggested that the emission is caused by the inverse-Compton scattering by ultra-relativistic electrons (∼50 MeV) in Jupiter's magn…
Far-infrared dust properties of highly dust-obscured active galactic nuclei from the AKARI and WISE all-sky surveys
Malkan, Matthew; Lam, Anson; Wright, Edward
The combination of the AKARI and WISE infrared all-sky surveys provides a unique opportunity to identify and characterize the most highly dust-obscured active galactic nuclei (AGNs) in the universe. Dust-obscured AGNs are not easily detectable and are potentially underrepresented in extragalactic surveys due to their high optical extinction, but a…
Clustering of extremely red objects in the AKARI NEP-deep field
Goto, Tomotsugu; Pearson, Chris; Jeong, Woong-Seob +6 more
We study the clustering property of extremely red objects (EROs) using Canada-France-Hawaii Telescope (CFHT) surveys with 0.55 deg2 in the AKARI north ecliptic pole (NEP) deep field. EROs are selected by the color criterion of r' - Ks > 3.66, which is equivalent to (R - Ks)Vega > 5. We conducted th…