A Self‐Consistent Study of Triaxial Black Hole Nuclei

Poon, M. Y.; Merritt, David

doi:10.1086/383190

Cited by 53 publications

(42 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The compatibility of the presence of a massive central mass with a modest or a maximal triaxiality of the system is also supported by the results of Poon & Merritt (2002, 2004, who find that stable triaxial configuration in system with cuspy density profiles can exist.…”

Section: Effects Due To a Central Massmentioning

confidence: 63%

Chaos and secular evolution of triaxial N-body galactic models due to an imposed central mass

Kalapotharakos

Voglis

Contopoulos

2004

A&A

View full text Add to dashboard Cite

Abstract.We investigate the response of triaxial non-rotating N-body models of elliptical galaxies with smooth centers, initially in equilibrium, under the presence of a central mass assumed to be due mainly to a massive central black hole. We examine the fraction of mass in chaotic motion and the resulting secular evolution of the models. Four cases of the size of the central mass are investigated, namely m = 0.0005, 0.0010, 0.0050, 0.0100 in units of the total mass of the galaxy. We find that a central mass with value m < 0.005 increases the mass fraction in chaotic motion from the level of 25−35% (that appears in the case of smooth centers) to the level of 50−80% depending on the value of m and on the initial maximum ellipticity of the system. However, most of this mass moves in chaotic orbits with Lyapunov numbers too small to develop chaotic diffusion in a Hubble time. Thus their secular evolution is so slow that it can be neglected in a Hubble time. Larger central masses (m > ∼ 0.005) give initially about the same fractions of mass in chaotic motion as for smaller m, but the Lyapunov numbers are concentrated to larger values, so that a secular evolution of the self-consistent models is prominent. These systems evolve in time tending to a new equilibrium. During their evolution they become self-organized by converting chaotic orbits to ordered orbits of the Short Axis Tube type. The mechanism of such a self-organization is investigated. The rate of this evolution depends on m and on the value of the initial maximum ellipticity of the system. For m = 0.01 and a large initial maximum ellipticity E max ≈ 7, equilibrium can be achieved in one Hubble time, forming an oblate spheroidal configuration. For the same value of m and initial maximum elipticity E max ≈ 3.5, or for E max ≈ 7, but m = 0.005, oblate equilibrium configurations can also be achieved, but in much longer times. Furthermore, we find that, for m = 0.005 and E max ≈ 3.5, triaxial equilibrium configurations can be formed. The fraction of mass in chaotic motion in the equilibrium configurations is in the range of 12−25%.

show abstract

Section: Effects Due To a Central Massmentioning

confidence: 63%

Chaos and secular evolution of triaxial N-body galactic models due to an imposed central mass

Kalapotharakos

Voglis

Contopoulos

2004

A&A

View full text Add to dashboard Cite

show abstract

“…The resulting chaotic orbits lead to an altered shape for the galaxy; the trend is toward shapes that are nearly spherical in the inner regions and nearly oblate in the outer regions ( Merritt & Quinlan 1998). In the inner regions, the orbits can support a shape that is nearly oblate, T $ 0:25, or strongly triaxial, T $ 0:5, but not nearly prolate, T $ 0:75 ( Poon & Merritt 2004). The timescale for the shape evolution depends on the mass of the central black hole relative to the total stellar mass of the galaxy.…”

Section: Discussionmentioning

confidence: 99%

The Dependence of Galaxy Shape on Luminosity and Surface Brightness Profile

Vincent

Ryden

2005

ApJ

View full text Add to dashboard Cite

For a sample of 96,951 galaxies from the Sloan Digital Sky Survey Data Release 3, we study the distribution of apparent axis ratios as a function of r-band absolute magnitude and surface brightness profile type. We use the parameter ''fracDeV'' to quantify the profile type (fracDeV ¼ 1 for a pure de Vaucouleurs profile; fracDeV ¼ 0 for a pure exponential profile). When the apparent axis ratio q am is estimated from the moments of the light distribution, the roundest galaxies are very bright (M r $ À23) de Vaucouleurs galaxies and the flattest are modestly bright (M r $ À18) exponential galaxies. When the axis ratio q 25 is estimated from the axis ratio of the 25 mag arcsec À2 isophote, we find that de Vaucouleurs galaxies, at this low surface brightness, are flatter than exponential galaxies of the same absolute magnitude. For a given surface brightness profile type, very bright galaxies are rounder, on average, than fainter galaxies. We deconvolve the distributions of apparent axis ratios to find the distribution of the intrinsic short-to-long axis ratio , making the assumption of constant triaxiality T. For all profile types and luminosities, the distribution of axis ratios is inconsistent with a population of oblate spheroids, but is usually consistent with a population of prolate spheroids. Bright galaxies with a de Vaucouleurs profile (M r À21:84, fracDeV > 0:9) have a distribution of q am that is consistent with triaxiality in the range 0:4 P T P 0:8, with mean axis ratio 0:66 P hi P 0:69. The fainter de Vaucouleurs galaxies are best fit with prolate spheroids (T ¼ 1) with mean axis ratio hi % 0:51.

show abstract

“…Various studies (Merritt & Fridman 1996;Rix et al 1997;Poon & Merritt 2004;Capuzzo-Dolcetta et al 2007) of Schwarzschild's technique applied to triaxial Dehnen profiles have been conducted, and it has been shown that self-consistent solutions for these models can be constructed in the case of Newtonian gravity.…”

Section: Introductionmentioning

confidence: 99%

Lopsidedness of Self-consistent Galaxies Caused by the External Field Effect of Clusters

Wang

Feix

et al. 2017

ApJ

View full text Add to dashboard Cite

Adopting Schwarzschild's orbit-superposition technique, we construct a series of self-consistent galaxy models, embedded in the external field of galaxy clusters in the framework of Milgrom's MOdified Newtonian Dynamics. These models represent relatively massive ellipticals with a Hernquist radial profile at various distances from the cluster centre. Using N -body simulations, we perform a first analysis of these models and their evolution. We find that self-gravitating axisymmetric density models, even under a weak external field, lose their symmetry by instability and generally evolve to triaxial configurations. A kinematic analysis suggests that the instability originates from both box and non-classified orbits with low angular momentum. We also consider a self-consistent isolated system which is then placed in a strong external field and allowed to evolve freely. This model, just as the corresponding equilibrium model in the same external field, eventually settles to a triaxial equilibrium as well, but has a higher velocity radial anisotropy and is rounder. The presence of an external field in MOND universe generically predicts some lopsidedness of galaxy shapes.

show abstract

A Self‐Consistent Study of Triaxial Black Hole Nuclei

Cited by 53 publications

References 28 publications

Chaos and secular evolution of triaxial N-body galactic models due to an imposed central mass

Chaos and secular evolution of triaxial N-body galactic models due to an imposed central mass

The Dependence of Galaxy Shape on Luminosity and Surface Brightness Profile

Lopsidedness of Self-consistent Galaxies Caused by the External Field Effect of Clusters

Contact Info

Product

Resources

About