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Black Hole Masses of Active Galaxies with Double-Peaked Balmer Emission Lines

Karen T. Lewis Michael Eracleous
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Abstract

We have obtained near-IR spectra of five Active Galactic Nuclei that exhibit double-peaked Balmer Emission Lines (NGC 1097, Pictor A, PKS 0921-213, 1E 0450.30-1817, and IRAS 0236.6-3101). The stellar velocity dispersions of the host galaxies were measured from the Ca II 8494,8542,8662 Angstrom absorption lines and were found to range from 140 to 200 km/s. Using the well-known correlation between the black hole mass and the stellar velocity dispersion, the black hole masses in these galaxies were estimated to range from 4x10^7 to 1.2x10^8 solar masses. We supplement the observations presented here with estimates of the black holes masses for five additional double-peaked emitters (Arp 102B, 3C 390.3, NGC 4579, NGC 4203, and M81) obtained by other authors using similar methods. Using these black hole masses, we infer the ratio of the bolometric luminosity to the Eddington luminosity, L_bol/L_Edd. We find that two objects (Pictor A and PKS 0921--213) have L_bol/L_Edd ~ 0.2, whereas the other objects have L_bol/L_Edd <~ 10^-2 (nearby, low-luminosity double-peaked emitters are the most extreme, with L_bol/L_Edd <~ 10^-4). The physical time scales in the outer regions of the accretion disks (at r ~ 10^3 GM/c^2) in these objects were also estimated and range from a few months, for the dynamical time scale, to several decades for the sound crossing time scale. The profile variability in these objects are typically an order of magnitude longer than the dynamical time, but we note that variability occurring on the dynamical time scale has not been ruled out by the observations.

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Karen T. Lewis Michael Eracleous. 2006-01-18. Black Hole Masses of Active Galaxies with Double-Peaked Balmer Emission Lines. https://doi.org/10.1086/501419

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