科研之友
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摘要
We propose a new method for estimating the mass of a supermassive black hole, applicable to obscured active galactic nuclei (AGNs). This method estimates the black hole mass using the width of the narrow core of the neutral FeK alpha emission line in X-rays and the distance of its emitting region from the black hole based on the isotropic luminosity indicator via the luminosity scaling relation. Assuming the virial relation between the locations and the velocity widths of the neutral FeK alpha line core and the broad H beta emission line, the luminosity scaling relation of the neutral FeK alpha line core emitting region is estimated. We find that the velocity width of the neutral FeK alpha line core falls between that of the broad Balmer emission lines and the corresponding value at the dust reverberation radius for most of the target AGNs. The black hole mass M-BII,FeK alpha estimated with this method is then compared with other black hole mass estimates, such as the broad emission-line reverberation mass M-BH,M-rev for type 1 AGNs, the mass M-BH,M-H2O based on the H2O maser, and the single-epoch mass estimate M-BH,M-pol based on the polarized broad Balmer lines for type 2 AGNs. We find that MBH,FeK alpha is consistent with M-BH,M-rev and M-BH,M- pol, and find that M-BH,FeK alpha correlates well with M-BH,HO2. These results suggest that MBH,FeK alpha is a potential indicator of the black hole mass for obscured AGNs. In contrast, MBH,FeK alpha is systematically larger than MBH,H2O by about a factor of 5, and the possible origins are discussed.
- 出版日期2015-4-1
