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Accepted: 2018-02-21

One of the most useful methods to estimate the black hole mass in X-ray Binaries (XBs), when the dynamical method is unavailable, is by X-ray spectral fitting. The most well-known fitting model for Black Hole Binaries (BHBs) is the Disk BlackBody (DBB) model, in which the effective temperature profile is assumed to be T(sub eff) is proportional to r(exp -3/4), where r is the disk radius. It has two fitting parameters: the innermost disk temperature, T(sub in), and the innermost radius, r(sub in). For a non-rotating black hole, its mass can be estimated by assuming that the innermost radius coincides with r(sub in) = 3r(sub g) (proportional to M), where r(sub g) is the Schwarzschild radius. However, this conventional method does not give an accurate mass for super-critical accretion flow, in which both of the innermost radius and temperature profile are modified from those of the sub-critical flow. We, here, propose a methodology to derive a black hole mass for the super-critical accretion flow. In this method, we use as a spectral fitting model, the extended DBB model, in which an effective temperature profile obeys the relation, T(sub eff) is proportional to r(exp -p), with the temperature gradient, p, being treated as a fitting parameter (in addition to two others; T(sub in) and r(sub in)). We first calculate theoretical flow structure and its spectra for given black hole mass and accretion rate, M and dot-M. Through the fitting to the theoretical spectra by the extended DBB model, we can estimate a black hole mass, M(sub x), assuming r(sub in) = 3r(sub g). We find, however, that the estimated mass deviates from that adopted in the spectral calculations, M, even for low dot-M cases. We also find that the deviations can be eliminated by introducing a new correction for the innermost radius. Using this correction, we calculate mass correction factors, M/M(sub x), in the super-critical regimes for some sets of M and dot-M, finding that a mass correction factor ranges

楕円銀河M87中心に存在する超巨大ブラックホール影とその周りの降着円盤は次世代のスペース電波干渉計VSOP-2の観測ターゲットである。今回、これらの観測可能性を調べた。まず、降着円盤に関しては、M87のVSOP-2の43GHzでの分解能・感度ともに1桁以上十分であるので検出は確実である。つぎに、ブラックホールに関しては、まず感度は十分である。VSOP-2(43GHz)の分解能ならばブラックホールの回転がいかなる場合でも検出可能性がある。今回の計算では星間散乱の影響を考慮していないが、M87中心で星間散乱によるイメージのぼかしの影響が著しい場合にはブラックホール影は観測できないであろう。

In explaining the spectral properties of active galactic nuclei (AGNs) and X-ray binaries, it is often assumed that they consists of a geometrically thin, optically thick disk and hot, optically thin corona surrounding the thin disk. As for a model of a corona, we adopt the simulation data of three-dimensional MHD accretion flows, while for a thin disk we assume a standard disk. We perform Monte Carlo radiative transfer simulations in the corona, taking into account the Compton scattering of the soft photons from the thin disk by hot thermal electrons. We can reproduce the emergent spectra which are consistent with those of typical Seyfert galaxies, and we also find the rapid time variability in X-ray emission spectra, originating from the density fluctuation in the corona., Meeting Information: The 3rd Suzaku international Conference "Energetic Cosmos : from Suzaku to ASTRO-H" (June 29-July 2, 2009. Grand Park Otaru Hotel), Otaru, Hokkaido Japan, Meeting sponsors: The University of Tokyo, The Institute of Physical and Chemical Research, The Japan Society for the Promotion of Science

In explaining the spectral properties of active galactic nuclei (AGNs) and X-ray binaries, it is often assumed that they consists of a geometrically thin, optically thick disk and hot, optically thin corona surrounding the thin disk. As for a model of a corona, we adopt the simulation data of three-dimensional, non-radiative MHD accretion flows calculated by Kato and coworkers, while for a thin disk we assume a standard type disk. We perform Monte Carlo radiative transfer simulations in the corona, taking into account the Compton scattering of the soft photons from the thin disk by hot thermal electrons and coronal irradiation heating of the thin disk, which emits blacbody radiation. By adjusting the density parameter of the MHD coronal flow, we can produce the emergent spectra which are consistent with those of typical Seyfert galaxies. Moreover, we find rapid time variability in X-ray emission spectra, originating from the density fluctuation produced by the magnetorotational instability in the MHD corona., Meeting Information: Astrophysics with All-Sky X-Ray observations: 3rd International MAXI Workshop (RIKEN, 10-12 June 2008)

Accepted: 2003-12-23