1,620 research outputs found

    Element Material Exposure Experiment by EFFU

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    The National Space Development Agency of Japan (NASDA) is planning to perform an 'Element Material Exposure Experiment' using the Exposed Facility Flyer Unit (EFFU). This paper presents an initial design of experiments proposed for this project by our company. The EFFU is installed on the Space Flyer Unit (SFU) as a partial model of the Space Station JEM exposed facility. The SFU is scheduled to be launched by H-2 rocket in January or February of 1994, then various tests will be performed for three months, on orbit of 500 km altitude, and it will be retrieved by the U.S. Space Shuttle and returned to the ground. The mission sequence is shown

    Effects of fluctuated salinity under sea ice on growth rates of some microalgae

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    第3回極域科学シンポジウム/第34回極域生物シンポジウム 11月26日(月) 国立極地研究所 3階ラウン

    Sulphur-isotopic composition of the deep-sea mussel Bathymodiolus marisindicus from currently active hydrothermal vents in the Indian Ocean

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    Sulphur-isotopic composition of soft tissues from bathymodiolus marisindicus collected from hydrothermal vents in the indian ocean was reported. the [delta]34s values of the soft tissues (+3[similar]+5‰ vs cañyon diablo troilite) were nearly identical to those from the associated hydrothermal fluid and chimney sulphides (+5 to +8‰), but were significantly different from that of the common seawater sulphate (+21‰), which suggested that the endosymbiotic bacteria used sulphide in the fluid as an energy source. transmission electron microscopic observation of the endosymbionts also suggested that the symbiont is a thioautotroph. bathymodiolus species, which depend on either sulphide or methane oxidation, or both, have a worldwide distribution. bathymodiolus marisindicus from the indian ocean has a close relationship with congeners in the pacific ocean as evidenced by form of symbiosis. biogeography and migration of the genus bathymodiolus based on the relevant data are briefly discussed.</p

    Current status and future plan of the Program of the Antarctic Syowa MST/IS radar (PANSY)

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    The Tenth Symposium on Polar Science/Special session: [S] Future plan of Antarctic research: Towards phase X of the Japanese Antarctic Research Project (2022-2028) and beyond, Tue. 3 Dec. / 2F Auditorium, National Institute of Polar Researc

    Suzaku Observations of Active Galactic Nuclei Detected in the Swift/BAT Survey: Discovery of "New Type" of Buried Supermassive Black Holes

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    We present the Suzaku broad band observations of two AGNs detected by the Swift/BAT hard X-ray (>15 keV) survey that did not have previous X-ray data, Swift J0601.9-8636 and Swift J0138.6-4001. The Suzaku spectra reveals in both objects a heavily absorbed power law component with a column density of NH =~ 10^{23.5-24} cm^{-2} that dominates above 10 keV, and an intense reflection component with a solid angle >~ 2π2\pi from a cold, optically thick medium. We find that these AGNs have an extremely small fraction of scattered light from the nucleus, <~ 0.5% with respect to the intrinsic power law component. This indicates that they are buried in a very geometrically-thick torus with a small opening angle and/or have unusually small amount of gas responsible for scattering. In the former case, the geometry of Swift J0601.9-8636 should be nearly face-on as inferred from the small absorption for the reflection component. The discovery of two such objects in this small sample implies that there must be a significant number of yet unrecognized, very Compton thick AGNs viewed at larger inclination angles in the local universe, which are difficult to detect even in the currently most sensitive optical or hard X-ray surveys.Comment: 4 pages, 3 figures, accepted for publication in ApJ Lette

    BAT AGN Spectroscopic Survey I: Spectral Measurements, Derived Quantities, and AGN Demographics

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    We present the first catalog and data release of the Swift-BAT AGN Spectroscopic Survey (BASS). We analyze optical spectra of the majority of AGN (77%, 641/836) detected based on their 14-195 keV emission in the 70-month Swift BAT all-sky catalog. This includes redshift determination, absorption and emission line measurements, and black hole mass and accretion rate estimates for the majority of obscured and un-obscured AGN (74%, 473/641) with 340 measured for the first time. With ~90% of sources at z<0.2, the survey represents a significant census of hard-X-ray selected AGN in the local universe. In this first catalog paper, we describe the spectroscopic observations and datasets, and our initial spectral analysis. The FWHM of the emission lines show broad agreement with the X-ray obscuration (~94%), such that Sy 1-1.8 have NH10^21.9 cm^-2. Seyfert 1.9 show a range of column densities. Compared to narrow line AGN in the SDSS, the X-ray selected AGN have a larger fraction of dusty host galaxies suggesting these types of AGN are missed in optical surveys. Using the most sensitive [OIII]/Hbeta and [NII]/Halpha emission line diagnostic, about half of the sources are classified as Seyferts, ~15% reside in dusty galaxies that lack an Hbeta detection, but for which the line upper limits imply either a Seyfert or LINER, ~15% are in galaxies with weak or no emission lines despite high quality spectra, and a few percent each are LINERS, composite galaxies, HII regions, or in known beamed AGN.Comment: Accepted ApJ, see www.bass-survey.com for dat

    Scattered X-rays in Obscured Active Galactic Nuclei and their Implications for Geometrical Structure and Evolution

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    We construct a new sample of 32 obscured active galactic nuclei (AGNs) selected from the Second XMM-Newton Serendipitous Source Catalogue to investigate their multiwavelength properties in relation to the "scattering fraction", the ratio of the soft X-ray flux to the absorption-corrected direct emission. The sample covers a broad range of the scattering fraction (0.1%-10%). A quarter of the 32 AGNs have a very low scattering fraction (smaller than 0.5%), which suggests that they are buried in a geometrically thick torus with a very small opening angle. We investigate correlations between the scattering fraction and multiwavelength properties. We find that AGNs with a small scattering fraction tend to have low [O III]lambda5007/X-ray luminosity ratios. This result agrees with the expectation that the extent of the narrow-line region is small because of the small opening angle of the torus. There is no significant correlation between scattering fraction and far-infrared luminosity. This implies that a scale height of the torus is not primarily determined by starburst activity. We also compare scattering fraction with black hole mass or Eddington ratio and find a weak anti-correlation between the Eddington ratio and scattering fraction. This implies that more rapidly growing supermassive black holes tend to have thicker tori.Comment: 13 pages, 10 figures, accepted for publication in Ap

    Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) VIII. A less biased view of the early co-evolution of black holes and host galaxies

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    We present ALMA [CII] line and far-infrared (FIR) continuum observations of three z>6z > 6 low-luminosity quasars (M1450>25M_{\rm 1450} > -25) discovered by our Subaru Hyper Suprime-Cam (HSC) survey. The [CII] line was detected in all three targets with luminosities of (2.49.5)×108 L(2.4 - 9.5) \times 10^8~L_\odot, about one order of magnitude smaller than optically luminous (M145025M_{\rm 1450} \lesssim -25) quasars. The FIR continuum luminosities range from <9×1010 L< 9 \times 10^{10}~L_\odot (3σ\sigma limit) to 2×1012 L\sim 2 \times 10^{12}~L_\odot, indicating a wide range in star formation rates in these galaxies. Most of the HSC quasars studied thus far show [CII]/FIR luminosity ratios similar to local star-forming galaxies. Using the [CII]-based dynamical mass (MdynM_{\rm dyn}) as a surrogate for bulge stellar mass (MbulgeM_{\rm bulge}), we find that a significant fraction of low-luminosity quasars are located on or even below the local MBHMbulgeM_{\rm BH} - M_{\rm bulge} relation, particularly at the massive end of the galaxy mass distribution. In contrast, previous studies of optically luminous quasars have found that black holes are overmassive relative to the local relation. Given the low luminosities of our targets, we are exploring the nature of the early co-evolution of supermassive black holes and their hosts in a less biased way. Almost all of the quasars presented in this work are growing their black hole mass at much higher pace at z6z \sim 6 than the parallel growth model, in which supermassive black holes and their hosts grow simultaneously to match the local MBHMbulgeM_{\rm BH} - M_{\rm bulge} relation at all redshifts. As the low-luminosity quasars appear to realize the local co-evolutionary relation even at z6z \sim 6, they should have experienced vigorous starbursts prior to the currently observed quasar phase to catch up with the relation.Comment: 19 pages, 11 figures, 4 tables. Accepted for publication in Publications of the Astronomical Society of Japan (PASJ
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