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We employ a high-resolution dissipationless N-body simulation of a galaxy cluster to investigate the impact of subhalo selection on the resulting velocity distributions. Applying a lower limit on the present bound mass of subhalos leads to…

Astrophysics · Physics 2009-11-11 A. Faltenbacher , J. Diemand

By combining galaxy tracers from high-resolution N-body and hydrodynamical simulations, we present a consistent picture of the behaviour of galaxy velocities in massive clusters. In haloes above ~ 10^14 Msun, the brightest satellite…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-20 Hao-Yi Wu , Oliver Hahn , August E. Evrard , Risa H. Wechsler , Klaus Dolag

Using cosmological N-body simulations we study the radial velocity distribution in dark matter haloes focusing on the lowest-order even moments, dispersion and kurtosis. We determine the properties of ten massive haloes in the simulation…

Astrophysics · Physics 2009-11-10 Radoslaw Wojtak , Ewa L. Lokas , Stefan Gottloeber , Gary A. Mamon

We present a statistical study of substructure within a sample of LCDM clusters and galaxies simulated with up to 25 million particles. With thousands of subhalos per object we can accurately measure their spatial clustering and velocity…

Astrophysics · Physics 2009-11-10 Juerg Diemand , Ben Moore , Joachim Stadel

We study the systematic bias introduced when selecting the spectroscopic redshifts of brighter cluster galaxies to estimate the velocity dispersion of galaxy clusters from both simulated and observational galaxy catalogues. We select…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 L. Old , M. E. Gray , F. R. Pearce

We derive the central stellar velocity dispersion function for quiescent galaxies in 280 massive clusters with $\log (M_{200} / M_{\odot}) > 14$ in IllustrisTNG300. The velocity dispersion function is an independent tracer of the dark…

Astrophysics of Galaxies · Physics 2024-06-03 Jubee Sohn , Margaret J. Geller , Josh Borrow , Mark Vogelsberger

We investigate the properties of the pairwise velocity dispersion as a function of galaxy luminosity in the context of a halo model. We derive the distribution of velocities of pairs at a given separation taking into account both one-halo…

Astrophysics · Physics 2009-11-11 Anze Slosar , Uros Seljak , Argyro Tasitsiomi

We carry out a detailed study of the orbital dynamics and structural evolution of over 6000 subhalos in the Via Lactea II simulation, from infall to present. By analyzing subhalos with masses down to m = 4e5 Msun, we find that lower mass…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-13 J. D. Emberson , Takeshi Kobayashi , Marcelo A. Alvarez

The initial orbits of infalling subhalos largely determine the subsequent evolution of the subhalos and satellite galaxies therein and shed light on the assembly of their hosts. Using a large set of cosmological simulations of various…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-06 Zhao-Zhou Li , Dong-Hai Zhao , Y. P. Jing , Jiaxin Han , Fu-Yu Dong

We use a high-resolution N-body simulation to study how the influence of large-scale structure in and around clusters causes correlated signals in different physical probes and discuss some implications this has for multi-physics probes of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Martin White , J. D. Cohn , Renske Smit

[Abridged] We present an analysis of the relation between the masses of cluster- and group-sized halos, extracted from $\Lambda$CDM cosmological N-body and hydrodynamic simulations, and their velocity dispersions, at different redshifts…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-04 Emiliano Munari , Andrea Biviano , Stefano Borgani , Giuseppe Murante , Dunja Fabjan

Dark matter sub-halos that pass near or through a thin tidal star stream locally increase its velocity dispersion. Subsequent orbital evolution further increases the velocity dispersion and stream width, lowering the surface density of a…

Astrophysics of Galaxies · Physics 2023-07-06 Raymond G. Carlberg , Hayley Agler

The orbital parameters of dark matter (DM) subhaloes play an essential role in determining their mass-loss rates and overall spatial distribution within a host halo. Haloes in cosmological simulations grow by a combination of relatively…

Astrophysics of Galaxies · Physics 2021-02-17 Go Ogiya , James E. Taylor , Michael J. Hudson

We examine the central stellar velocity dispersion of subhalos based on IllustrisTNG cosmological hydrodynamic simulations. The central velocity dispersion is a fundamental observable that links galaxies with their dark matter subhalos. We…

Astrophysics of Galaxies · Physics 2024-02-23 Jubee Sohn , Margaret J. Geller , Josh Borrow , Mark Vogelsberger

We study the distribution functions of mass and circular velocity for dark matter halos in N-body simulations of the $\Lambda$CDM cosmology, addressing redshift and environmental dependence. The dynamical range enables us to resolve…

Early-type galaxies (ETGs) are observed to be more compact, on average, at $z \gtrsim 2$ than at $z\simeq 0$, at fixed stellar mass. Recent observational works suggest that such size evolution could reflect the similar evolution of the host…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Lorenzo Posti , Carlo Nipoti , Massimo Stiavelli , Luca Ciotti

The velocity anisotropy of particles inside dark matter (DM) haloes is an important physical quantity, which is required for the accurate modelling of mass profiles of galaxies and clusters of galaxies. It is typically measured using the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Radoslaw Wojtak , Stefan Gottloeber , Anatoly Klypin

The hierarchical mergers that form the haloes of dark matter surrounding galaxies, groups and clusters are not entirely efficient, leaving substantial amounts of dense substructure, in the form of stripped halo cores or `subhaloes',…

Astrophysics · Physics 2009-11-07 James E. Taylor , Arif Babul

We combine 10 high resolution resimulations of cluster--sized dark haloes with semi--analytic galaxy formation modelling in order to compare the number density and velocity dispersion profiles of cluster galaxies with those of dark matter…

Astrophysics · Physics 2009-09-25 Liang Gao , Gabriella De Lucia , Simon D. M. White , Adrian Jenkins

We consider a sample of 51 distant galaxy clusters at 0.15<z<0.9 (<z> about 0.3), each cluster having at least 10 galaxies with available redshift in the literature. We select member galaxies, analyze the velocity dispersion profiles, and…

Astrophysics · Physics 2009-10-31 M. Girardi , M. Mezzetti
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