Implications of the X-ray Variability for the Mass of MCG-6-30-15

Abstract

The bright Seyfert 1 galaxy \mcg shows large variability on a variety of time scales. We study the $\aproxlt 3$ day time scale variability using a set of simultaneous archival observations that were obtained from \rxte and the {\it Advanced Satellite for Cosmology and Astrophysics} (\asca). The \rxte\ observations span nearly $10^6$ sec and indicate that the X-ray Fourier Power Spectral Density has an rms variability of 16%, is flat from approximately 10^{-6} - 10^{-5} Hz, and then steepens into a power law $\propto f^{-\alpha }$ with $α\aproxgt 1$. A further steepening to $\alpha \approx 2$ occurs between 10^{-4}-10^{-3} Hz. The shape and rms amplitude are comparable to what has been observed in \ngc and \cyg, albeit with break frequencies that differ by a factor of 10^{-2} and 10^{4}, respectively. If the break frequencies are indicative of the central black hole mass, then this mass may be as low as $10^6{\mathrm{M}}_{\odot }$. An upper limit of $\sim 2$ ks for the relative lag between the 0.5-2 keV \asca band compared to the 8-15 keV \rxte band was also found. Again by analogy with \ngc and \cyg, this limit is consistent with a relatively low central black hole mass.

5 pages, 3 figures, LaTeX, uses emulateapj.sty and apjfonts.sty, revised version, accepted for publication in ApJ Letters

References in corpus (4)

• Keplerian Motion of Broad-Line Region Gas as Evidence for Supermassive Black Holes in Active Galactic Nuclei
• Simultaneous EUVE/ASCA/RXTE Observations of NGC 5548
• Variation of the broad X-ray iron line in MCG-6-30-15 during a flare
• Iron line reverberation mapping with Constellation-X

Cited by in corpus (26)

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• Frequency-dependent time lags in the X-ray emission of the Seyfert galaxy NGC 7469
• Evidence for Rapid Iron K_alpha Line Flux Variability in MCG--6-30-15
• The X-ray variability of the Seyfert~1 galaxy MCG-6-30-15 from long ASCA and RXTE observations
• Black hole masses from power density spectra: determinations and consequences
• The continuum variability of MCG--6-30-15: A detailed analysis of the long 1999 ASCA observation
• The relationship between the X-ray variability and the central black hole mass
• Relativistic O VIII Emission and Ionized Outflow in NGC 4051
• Temporal characteristics of the X-ray emission of NGC 7469
• Detection of a high frequency break in the X-ray power spectrum of Ark 564
• Evidence for an intermediate mass black hole and a multi-zone warm absorber in NGC 4395
• Variable line profiles due to non-axisymmetric patterns in an accretion disc around a rotating black hole
• The Nature of the Emission Components in the Quasar/NLS1 PG1211+143
• On the inability of Comptonization to produce the broad X-ray iron lines observed in Seyfert nuclei
• The Black Hole and Central Stellar Population of MCG--6-30-15
• Estimation of relativistic accretion disk parameters from iron line emission
• Comptonization in the vicinity of black hole horizon
• X-ray variability of AGN and correlations with spectral properties
• Testing a model of variability of X-ray reprocessing features in Active Galactic Nuclei
• Theory of disk accretion onto supermassive black holes
• Long-term X-ray variability of quasars in the Lockman Hole field observed with ROSAT
• X-ray energy and power spectra of Seyfert 1 and Narrow Line Seyfert 1 galaxies: comparison to Black Hole Binaries