Aoyama Gakuin University

About: Aoyama Gakuin University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Superconductivity & Thin film. The organization has 3494 authors who have published 6419 publications receiving 115648 citations. The organization is also known as: Aoyama gakuin daigaku.

Revisit of Local X-Ray Luminosity Function of Active Galactic Nuclei with the MAXI Extragalactic Survey

Abstract: We constructed a new X-ray (2–10 keV) luminosity function of Compton-thin active galactic nuclei (AGNs) in the local universe, using the first MAXI/GSC source catalog surveyed in the 4–10 keV band. The sample consists of 37 non-blazar AGNs at z = 0.002–0.2, whose identification is highly (>97%) complete. We confirmed the trend that the fraction of absorbed AGNs withNH > 10 cm 2 rapidly decreases against the luminosity (LX), from 0.73 0.10 at LX = 10 43:5 erg s 1 to 0.12 0.08 at LX = 1043:5–45:5 erg s . The obtained luminosity function was well-fitted with a smoothly connected double power-law model whose indices are 1 = 0.84 (fixed) and 2 = 2.0 0.2 below and above the break luminosity, L = 1043:3 0:4 erg s , respectively. While the result of the MAXI/GSC agrees well with that of HEAO-1 at LX & 10 erg s , it gives a larger number density at the lower luminosity range. A comparison between our luminosity function in the 2–10 keV band and that in the 14–195 keV band obtained from the Swift/BAT survey indicates that the averaged broad-band spectra in the 2–200 keV band should depend on the luminosity, approximated by Γ 1.7 for LX . 10 erg s , while Γ 2.0 for LX & 10 erg s . This trend was confirmed by the correlation between the luminosities in the 2–10 keV and 14–195 keV bands in our sample. We argue that there is no contradiction in the luminosity functions between above and below 10 keV once this effect is taken into account.

Were, would, might and a compositional account of counterfactuals

Abstract: This paper has two purposes. We first give a new dynamic account of epistemic modal operators that account for both their test-like behaviour with respect to whole information states and their capacity to induce quantificational dependencies across worlds (modal subordination). We then use this theory, together with an analysis of conditionals and irrealis moods, to give a fully compositional semantics of indicative and counterfactual conditionals. In our analysis, the distinction between counterfactual and indicative conditionals follows directly from the interaction between the semantics of the conditional and irrealis operators and the semantics of the particular modals involved in the conditional consequent. We indicate some theoretical and logical consequences of our approach.