NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-06-25 T04:53:16 PDT
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For refcode 2004MNRAS.350L..26N:
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Copyright by Royal Astronomical Society. 2004MNRAS.350L..26N Black hole mass estimation from X-ray variability measurements in active galactic nuclei Nikolajuk, M.; Papadakis, I. E.; Czerny, B. Abstract. We propose a new method of estimation of the black hole masses in active galactic nuclei (AGN) based on the normalized excess variance, {sigma}^2^_nxs_. We derive a relation between {sigma}^2^_nxs_, the length of the observation, T, the light-curve bin size, {DELTA}t, and the black hole mass, assuming that (i) the power spectrum above the high-frequency break, {nu}_bf_, has a slope of -2, (II) the high-frequency break scales with black hole mass, (III) the power-spectrum amplitude (in frequency-power space) is universal and (IV) {sigma}^2^_nxs_ is calculated from observations of length T < 1/{nu}_bf_. Values of black hole masses in AGN obtained with this method are consistent with estimates based on other techniques such as reverberation mapping or the M_BH_-stellar velocity dispersion relation. The method is formally equivalent to methods based on power spectrum scaling with mass, but the use of {sigma}^2^_nxs_ has the big advantage of being applicable to relatively low-quality data. Keywords: galaxies: active, galaxies: Seyfert, X-rays: galaxies
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