Understanding the Nuclear Gas Dispersion in Early-Type Galaxies in the Context of Black Hole Demographics

Abstract

(abridged) We analyze and model HST /STIS observations of a sample of 27 galaxies; 16 Fanaroff & Riley Type I radio galaxies and 11 (more) normal early-type galaxies. We focus here on what can be learned from the nuclear velocity dispersion (line width) of the gas as a complement to the many studies dealing with gas rotation velocities. We find that the dispersion in a STIS aperture of ~0.1''-0.2'' generally exceeds the large-scale stellar velocity dispersion of the galaxy. This is qualitatively consistent with the presence of central BHs, but raises the question whether the excess gas dispersion is of gravitational or non-gravitational origin and whether the implied BH masses are consistent with our current understanding of BH demography(as predicted by the M-sigma relation between BH mass and stellar velocity dispersion). To address this we construct dynamical models for the gas, both thin disk models and models with more general axis ratios and velocity anisotropies. For the normal galaxies the nuclear gas dispersions are adequately reproduced assuming disks around BHs with masses that follow the M-sigma relation. In contrast, the gas dispersions observed for the radio galaxies generally exceed those predicted by any of the models. We attribute this to the presence of non-gravitational motions in the gas that are similar to or larger than the gravitational motions. The non- gravitational motions are presumably driven by the active galactic nucleus (AGN), but we do not find a relation between the radiative output of the AGN and the non-gravitational dispersion. It is not possible to uniquely determine the BH mass for each galaxy from its nuclear gas dispersion. However, for the sample as a whole the observed dispersions do not provide evidence for significant deviations from the M-sigma relation.

arXiv commentaccepted for publication in the Astronomical Journal

References in corpus (33)

• A Fundamental Relation Between Supermassive Black Holes and Their Host Galaxies
• A Relationship Between Nuclear Black Hole Mass and Galaxy Velocity Dispersion
• The slope of the black-hole mass versus velocity dispersion correlation
• The Relation between Black Hole Mass, Bulge Mass, and Near-Infrared Luminosity
• On the Black Hole Mass - Bulge Mass Relation
• The SBF Survey of Galaxy Distances. IV. SBF Magnitudes, Colors, and Distances
• SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. II. The Source Catalogue
• The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy's Central Black Hole: A Paradox of Youth
• The Spectral Energy Distributions of Low-Luminosity Active Galactic Nuclei
• A Search for "Dwarf" Seyfert Nuclei. V. Demographics of Nuclear Activity in Nearby Galaxies
• The supermassive black hole of M87 and the kinematics of its associated gaseous disk
• Axisymmetric Dynamical Models of the Central Regions of Galaxies
• Stellar dynamics in the central arcsecond of our galaxy
• Dust in the Cores of Early-Type Galaxies
• M-BH - sigma relation for a Complete Sample of Soft X-ray Selected AGNs
• The counterrotating core and the black hole mass of IC1459
• The Centers of Early-Type Galaxies with HST III: Non-Parametric Recovery of Stellar Luminosity Distributions
• Hubble Space Telescope Imaging of Brightest Cluster Galaxies
• Evidence for a 3 x 10^8 solar mass black hole in NGC 7052 from HST observations of the nuclear gas disk
• Dusty Nuclear Disks and Filaments in Early Type Galaxies
• Evidence for a Supermassive Black Hole in the S0 Galaxy NGC 3245
• SuperMassive Black Holes in Bulges
• Kinematics of the Nuclear Ionized Gas in the Radio Galaxy M84 (NGC 4374)
• Nuclear Disks of Gas and Dust in Early Type Galaxies and the Hunt for Massive Black Holes: Hubble Space Telescope Observations of NGC 6251
• HST observations of nearby radio-loud early-type galaxies
• The black hole in IC 1459 from HST observations of the ionized gas disk
• Kinematics from spectroscopy with a wide slit: detecting black holes in galaxy centres
• Limits on the Mass of the Central Black Hole in 16 Nearby Bulges
• The Frequency Function of Elliptical Galaxy Intrinsic Shapes
• The HST view of the nuclear emission line region in low luminosity radio-galaxies
• STIS spectroscopy of the emission line gas in the nuclei of nearby FR-I galaxies
• Gas Kinematics and the Black Hole Mass at the Center of the Radio Galaxy NGC 4335
• Scale-free dynamical models for galaxies: flattened densities in spherical potentials

Cited by in corpus (20)

• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• Nuclear Activity in Nearby Galaxies
• Cause and Effect of Feedback: Multiphase Gas in Cluster Cores Heated by AGN Jets
• The Black Hole Mass, Stellar M/L, and Dark Halo in M87
• Bondi flow from a slowly rotating hot atmosphere
• Unobscured Type 2 AGNs
• Origin and Dynamical Support of Ionized Gas in Galaxy Bulges
• Upper Limits on the Masses of 105 Supermassive Black Holes from Hubble Space Telescope/Space Telescope Imaging Spectrograph Archival Data
• The High-Mass End of the Black Hole Mass Function: Mass Estimates in Brightest Cluster Galaxies
• Black Hole Mass Measurements of Radio Galaxies NGC 315 and NGC 4261 Using ALMA CO Observations
• Supermassive black holes in the Sbc spiral galaxies NGC 3310, NGC 4303 and NGC 4258
• Spectroscopy of High Energy BL Lac Objects with X-shooter on the VLT
• Dense gas without star formation: The kpc-sized molecular disk in 3C326 N
• The Supermassive Black Hole in M84 Revisited
• Hubble Space Telescope Spectroscopic Observations of the Narrow-Line Region in Nearby Low-Luminosity Active Galactic Nuclei
• Toward Precision Black Hole Masses with ALMA: NGC 1332 as a Case Study in Molecular Disk Dynamics
• The Mysterious Merger of NGC6868 and NGC6861 in the Telescopium Group
• WISDOM Project -- VII. Molecular gas measurement of the supermassive black hole mass in NGC 7052
• The Mass of the Black Hole in NGC 5273 from Stellar Dynamical Modeling
• Upper limits on the mass of supermassive black holes from HST/STIS archival data