Fueling nuclear activity in disk galaxies: Starbursts and monsters

Heller, Clayton; Shlosman, Isaac

doi:10.1086/173874

Cited by 222 publications

(252 citation statements)

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“…Gas dynamics in a barred potential have been well studied in numerical simulations (Wada & Habe 1992;Heller & Shlosman 1994;Piner et al 1995;Fukuda et al 1998;). Our models evolve consistently with these simulations.…”

Section: Gas Dynamical Evolutionmentioning

confidence: 99%

Intrinsic errors of the central galactic mass derived from rotation curves under the influence of a weak non-axisymmetric potential

Koda

Wada

2002

A&A

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Abstract. Rotation curves are often used to estimate the mass distribution of spiral galaxies, assuming that the circular velocities of the interstellar medium balance with the galactic centrifugal force. However, non-circular motions caused by a non-axisymmetric gravitational potential, such as a stellar bar, may disturb the velocity field, resulting in errors in mass estimation, especially in the central regions of galaxies. This is because the line-of-sight velocity depends on the viewing angles in a non-axisymmetric flow. Observing rotation curves of edge-on galaxies in time-dependent numerical simulations from different viewing angles, we obtain errors in the estimation of galactic mass from the rotation curves. In the most extreme case, the ellipticity of gas orbits is as high as e ∼ 0.8 in the central regions, even if the bar potential is weak. When rotation curves are defined as the highest velocity envelope of position-velocity diagrams, the mass estimated from the rotation curves is larger than the true mass by a factor of five for 15% of the viewing angles, and the ratio between the apparent mass and true mass is less than six for any viewing angle. The overestimation in mass occurs more frequently than the underestimation.

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Section: Gas Dynamical Evolutionmentioning

confidence: 99%

Intrinsic errors of the central galactic mass derived from rotation curves under the influence of a weak non-axisymmetric potential

Koda

Wada

2002

A&A

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“…A&A 569, A37 (2014) of major mergers, as violent relaxation starts, the gas experiences rapidly varying gravitational torques and suffers strong shocks which can effectively result in large gas inflows in the central region (see Hopkins et al 2010 and references therein). In the case of isolated galaxies, recent simulations show thatas the disky material at smaller radii becomes self-gravitatingthe large-scale bars might indeed trigger a cascade of secondary gravitational instabilities that transport the gas towards the centre (Hopkins & Quataert 2010); the latter process resembles the "bars within bar" scenario (see Shlosman et al 1989;Friedli & Martinet 1993;Heller & Shlosman 1994;Maciejewski & Sparke 2000) but includes a wider range of morphologies in the nuclear region.…”

Section: Introductionmentioning

confidence: 99%

Triggering active galactic nuclei in hierarchical galaxy formation: disk instability vs. interactions

Menci

Gatti

Fiore

et al. 2014

A&A

141

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Using a state-of-the-art semi analytic model for galaxy formation, we investigated in detail the effects of black hole (BH) accretion triggered by disk instabilities (DI) in isolated galaxies on the evolution of the AGN population. Specifically, we took on, developed, and expanded the Hopkins & Quataert (2011, MNRAS, 411, 1027 model for the mass inflow following disk perturbations, based on a physical description of nuclear inflows and tested against aimed N-body simulations. We compared the evolution of AGN due to such a DI accretion mode with that arising in a scenario where galaxy interactions (IT mode) produce the sudden destabilization of large quantities of gas feeding the AGN; this constitutes the standard AGN feeding mode implemented in the earliest versions of most semi-analytic models. To study the maximal contribution of DI to the evolution of the AGN population, we extended and developed the DI model to assess the effects of changing the assumed disk surface density profile, and to obtain lower limits for the nuclear star formation rates associated to the DI accretion mode. We obtained the following results: i) For AGN with luminosity M 1450 > ∼ −26, the DI mode can provide the BH accretion needed to match the observed AGN luminosity functions up to z ≈ 4.5. In such a luminosity range and redshift, it constitutes a viable candidate mechanism to fuel AGN, and can compete with the IT scenario as the main driver of cosmological evolution of the AGN population. ii) The DI scenario cannot provide the observed abundance of high-luminosity QSO with M 1450 ≤ −26 AGN, as well as the abundance of high-redhshift z > ∼ 4.5 QSO with M 1450 ≤ −24. As found in our earliest works, the IT scenario provides an acceptable match to the observed luminosity functions up to z ≈ 6. iii) The dispersion of the distributions of Eddington ratio λ for low-and intermediate-luminosity AGN (bolometric L AGN = 10 43 −10 45 erg s −1 ) is predicted to be much smaller in the DI scenario compared to the IT mode. iv) The above conclusions concerning the DI mode are robust with respect to the explored variants of the DI model. We discuss the physical origin of our findings. Finally, we discuss how it is possible to pin down the dominant fueling mechanism of AGN in the low-intermediate luminosity range M 1450 > ∼ −26 where the DI and the IT modes are both viable candidates as the main drivers of the AGN evolution. We show that an interesting discriminant could be provided by the fraction of AGN with high Eddington ratios λ ≥ 0.5, since it increases with luminosity in the IT case, while the opposite is true in the DI scenario.

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“…The effect of large-scale bars has been studied in detail by simulations which have successfully shown that bars are very efficient for transporting the gas toward the center (e.g., Sparke & Sellwood 1987;Athanassoula 1992;Shlosman & Noguchi 1993;Heller & Shlosman 1994;Athanassoula 2003). As these mechanisms may work on different spatial scales, secondary bars within large-scale bars (e.g., Shlosman et al 1989;Friedli & Martinet 1993;Maciejewski & Sparke 2000;Heller et al 2001;Shlosman & Heller 2002;Englmaier & Shlosman 2004), gaseous spiral density waves (e.g., Englmaier & Shlosman 2000;Maciejewski 2002Maciejewski , 2004aMaciejewski , 2004b, m = 1 perturbations (e.g., Shu et al 1990;Junqueira & Combes 1996;García-Burillo et al 2000), and nuclear warps (Schinnerer et al 2000) have been suggested to transport the gas into the center.…”

Section: Introductionmentioning

confidence: 99%

Dynamical Evolution of Agn Host Galaxies—gas in/Out-Flow Rates in Seven Nuga Galaxies

Haan¹,

Schinnerer²,

Emsellem³

et al. 2009

ApJ

113

119

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To examine the role of the host galaxy structure in fueling nuclear activity, we estimated gas flow rates from several kpc down to the inner few 10 pc for seven nearby spiral galaxies, selected from the NUclei of GAlaxies sample. We calculated gravitational torques from near-infrared images and determined gas in/out-flow rates as a function of radius and location within the galactic disks, based on high angular resolution interferometric observations of molecular (CO using Plateau de Bure interferometer) and atomic (H i using the Very Large Array) gas. The results are compared with kinematic evidence for radial gas flows and the dynamical state of the galaxies (via resonances) derived from several different methods. We show that gravitational torques are very efficient at transporting gas from the outer disk all the way into the galaxies centers at ∼100 pc; previously assumed dynamical barriers to gas transport, such as the corotation resonance of stellar bars, seem to be overcome by gravitational torque induced gas flows from other nonaxisymmetric structures. The resulting rates of gas mass inflow range from 0.01 to 50 M yr −1 and are larger for the galaxy center than for the outer disk. Our gas flow maps show the action of nested bars within larger bars for three galaxies. Noncircular streaming motions found in the kinematic maps are larger in the center than in the outer disk and appear to correlate only loosely with the in/out-flow rates as a function of radius. We demonstrate that spiral gas disks are very dynamic systems that undergo strong radial evolution on timescales of a few rotation periods (e.g., 5×108 yrs at a radius of 5 kpc), due to the effectiveness of gravitational torques in redistributing the cold galactic gas.

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Fueling nuclear activity in disk galaxies: Starbursts and monsters

Cited by 222 publications

References 0 publications

Intrinsic errors of the central galactic mass derived from rotation curves under the influence of a weak non-axisymmetric potential

Intrinsic errors of the central galactic mass derived from rotation curves under the influence of a weak non-axisymmetric potential

Triggering active galactic nuclei in hierarchical galaxy formation: disk instability vs. interactions

Dynamical Evolution of Agn Host Galaxies—gas in/Out-Flow Rates in Seven Nuga Galaxies

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