@inproceedings{oai:jaxa.repo.nii.ac.jp:00038437,
 author = {Vierdayanti, Kiki and 渡會, 兼也 and 嶺重, 慎 and Vierdayanti, Kiki and Watarai, Kenya and Mineshige, Shin},
 book = {宇宙圏研究会高エネルギー宇宙物理連絡会,第8回研究会集録原稿:超新星とその残骸, Proceedings of the 8th Workshop of High Energy AstroPhysics Association, Workshop for Space Astrophysics: Supernova and Its Remnant},
 month = {Oct},
 note = {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 between M/M(sub x) is approximately 1.2-1.6. The higher dot-M is, the larger the mass correction factor tends to be. Since the correction is relatively small, we can safely conclude that the black holes in ULXs (UltraLuminous X-ray sources) which Vierdayanti et al. (2006) analyzed are stellar-mass black holes with mass less than 100 solar mass., 資料番号: AA0063722008},
 pages = {181--186},
 publisher = {宇宙航空研究開発機構宇宙科学研究本部, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA/ISAS)},
 title = {On black hole mass estimation from X-ray spectra of ultraluminous X-ray sources},
 year = {2007}
}