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We develop a flexible set of action-based distribution functions (DFs) for stellar haloes. The DFs have five free parameters, controlling the inner and outer density slope, break radius, flattening and anisotropy respectively. The DFs…

Astrophysics of Galaxies · Physics 2015-09-30 A. A. Williams , N. W. Evans

A numerical detection of the radius-dependent spin transition of dark matter halos is reported. Analyzing the data from the IllustrisTNG simulations, we measure the halo spin vectors at several inner radii within the virial boundaries and…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-09 Jun-Sung Moon , Jounghun Lee

In the previous papers in this series, we have measured the stellar and \hi content in a sample of edge-on galaxies. In the present paper, we perform a simultaneous rotation curve and vertical force field gradient decomposition for five of…

Astrophysics of Galaxies · Physics 2016-10-26 S. P. C. Peters , P. C. van der Kruit , R. J. Allen , K. C. Freeman

Using spectral methods, we analyse the orbital structure of prolate/triaxial dark matter (DM) halos in N-body simulations to understand the processes that drive the evolution of shapes of DM halos and elliptical galaxies in which central…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 M. Valluri , V. P. Debattista , T. Quinn , B. Moore

We study the statistical properties (such as shape and spin) of high-z halos likely hosting the first (PopIII) stars with cosmological simulations including detailed gas physics. In the redshift range considered ($11 < z < 16$) the average…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-03 Rafael S. de Souza , Benedetta Ciardi , Umberto Maio , Andrea Ferrara

We present a set of N-body simulations of a class of models in which an unstable dark matter particle decays into a stable non-interacting dark matter particle, with decay lifetime comparable to the Hubble time. We study the effects of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Mei-Yu Wang , Annika H. G. Peter , Louis E. Strigari , Andrew R. Zentner , Bryan Arant , Shea Garrison-Kimmel , Miguel Rocha

Using a series of high-resolution N-body simulations of the concordance cosmology we investigate how the formation histories, shapes and angular momenta of dark-matter haloes depend on environment. We first present a classification scheme…

Astrophysics · Physics 2008-11-26 Oliver Hahn , Cristiano Porciani , C. Marcella Carollo , Avishai Dekel

A longstanding puzzle of fundamental importance in modern cosmology has been the origin of the nearly universal density profiles of dark matter halos found in N-body simulations -- the so-called NFW profile. We show how this behavior may be…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-25 Neal Dalal , Yoram Lithwick , Michael Kuhlen

We have resimulated the six galaxy-sized haloes of the Aquarius Project including metal-dependent cooling, star formation and supernova feedback. This allows us to study not only how dark matter haloes respond to galaxy formation, but also…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Patricia B. Tissera , Simon D. M. White , Susana Pedrosa , Cecilia Scannapieco

We present new constraints on the density profiles of dark matter (DM) halos in seven nearby dwarf galaxies from measurements of their integrated stellar light and gas kinematics. The gas kinematics of low mass galaxies frequently suggest…

We consider a two-parametric family of radially anisotropic models with non-singular density distribution in the centre. If highly eccentric orbits are locked near the centre, the characteristic growth rate of the instability is much less…

Astrophysics of Galaxies · Physics 2015-08-06 E. V. Polyachenko , I. G. Shukhman

We present multi-tracer dynamical models of the low mass ($M_{*} \sim 10^{7}$), isolated dwarf irregular galaxy WLM in order to simultaneously constrain the inner slope of the dark matter (DM) halo density profile ($\gamma$) and flattening…

We perform controlled N-Body/SPH simulations of disk galaxy formation by cooling a rotating gaseous mass distribution inside equilibrium cuspy spherical and triaxial dark matter halos. We systematically study the angular momentum transport…

Astrophysics · Physics 2008-11-26 Tobias Kaufmann , Lucio Mayer , James Wadsley , Joachim Stadel , Ben Moore

We use the recently completed one billion particle Via Lactea II LambdaCDM simulation to investigate local properties like density, mean velocity, velocity dispersion, anisotropy, orientation and shape of the velocity dispersion ellipsoid,…

There is good evidence from N-body simulations that the velocity distribution in the outer parts of halos is radially anisotropic, with the kinetic energy in the radial direction roughly equal to the sum of that in the two tangential…

Astrophysics · Physics 2007-05-23 N. W. Evans , J. An

We examined the reliability of estimates of pseudoisothermal, Burkert and NFW dark halo parameters for the methods based on the mass-modelling of the rotation curves.To do it we constructed the $\chi^2$ maps for the grid of the dark matter…

Astrophysics of Galaxies · Physics 2016-08-24 Anna Saburova , Anastasia Kasparova , Ivan Katkov

We expand our previous study on the relationship between changes in the orientation of the angular momentum vector of dark matter haloes ("spin flips") and changes in their mass (Bett & Frenk 2012), to cover the full range of halo masses in…

Astrophysics of Galaxies · Physics 2016-07-06 Philip E. Bett , Carlos S. Frenk

We summarize recent developments in the use of spectral methods for analyzing large numbers of orbits in N-body simulations to obtain insights into the global phase space structure of dark matter halos. The fundamental frequencies of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Monica Valluri , Victor P. Debattista , Tom Quinn , Ben Moore

Perturbations of rotating relativistic stars can be classified by their behavior under parity. For axial perturbations (r-modes), initial data with negative canonical energy is found with angular dependence $e^{im\phi}$ for all values of…

General Relativity and Quantum Cosmology · Physics 2009-10-30 John L. Friedman , Sharon M. Morsink

We investigate the structure of cold dark matter halos using advanced models of spherical collapse and accretion in an expanding Universe. These base on solving time-dependent equations for the moments of the phase-space distribution…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 A. Lapi , A. Cavaliere
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