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Related papers: Galaxy Groups in Cold + Hot and CDM Universes: Com…

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We present techniques for identifying and analyzing galaxy groups and show that they provide a powerful discriminator between cosmological models. We apply these to high-resolution PM N-body simulations of structure formation in CHDM…

Astrophysics · Physics 2009-09-25 R. Nolthenius , A. A. Klypin , J. R. Primack

We present a series of four simulations of Cold Dark Matter (CDM) and Cold + Hot Dark Matter (CHDM) cosmologies. We discuss the power spectrum and correlation functions in real and redshift space, with comparisons to the CfA2 and IRAS…

Astrophysics · Physics 2016-08-30 A. Klypin , R. Nolthenius , J. Primack

The differences between cold (CDM) and warm (WDM) dark matter in the formation of a group of galaxies is examined by running two identical simulations where in the WDM case the initial power spectrum has been altered to mimic a 1keV dark…

We present the first self-consistently computed results on the evolution of X-ray properties of galaxy clusters in a Cold + Hot Dark Matter (CHDM) model. We have performed a hydrodynamic plus N-body simulation for the COBE-compatible CHDM…

Astrophysics · Physics 2009-10-22 Greg L. Bryan , Anatoly Klypin , Chris Loken , Michael L. Norman , Jack O. Burns

We use the moments of counts of neighbors as given by the Generalized Correlation Integrals, to study the clustering properties of Dark Matter Halos (DH) in Cold Dark Matter (CDM) and Cold+Hot Dark Matter (CHDM) models. We compare the…

Astrophysics · Physics 2016-08-30 A. Campos , G. Yepes , A. Klypin , G. Murante , A. Provenzale , S. Borgani

Here we discuss what are perhaps the two most popular variants of CDM that might agree with the data: \lcdm\ and CHDM. While the predictions of COBE-normalized \lcdm\ and CHDM both agree well with the available data on scales of $\sim 10$…

Astrophysics · Physics 2009-10-28 Joel Primack , Anatoly Klypin

We use high resolution PM N-body simulations to follow the development of non-linear clustering in a flat Universe, dominated by Cold + Hot Dark Matter (CHDM) with 60% of CDM, 30% of HDM and 10% of baryons; a simulation box of 100 Mpc a…

Astrophysics · Physics 2015-06-24 S. A. Bonometto , S. Borgani , S. Ghigna , A. Klypin , J. R. Primack

We examine high-resolution gravitational N-body simulations of the $\Omega=1$ cold dark matter (CDM) model in order to determine whether there is any normalization of the initial density fluctuation spectrum that yields acceptable results…

Astrophysics · Physics 2009-10-22 James M. Gelb , Edmund Bertschinger

A robust prediction of $\Lambda{\rm CDM}$ cosmology is the halo circular velocity function (CVF), a dynamical cousin of the halo mass function. The correspondence between theoretical and observed CVFs is uncertain, however: cluster galaxies…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Louis E. Abramson , Rik J. Williams , Andrew J. Benson , Juna A. Kollmeier , John S. Mulchaey

We present zoom-in N-body + Hydrodynamic simulations of dwarf central galaxies formed in Warm Dark Matter (WDM) halos with masses at present-day of $2-4\times 10^{10}$ \msun. Two different cases are considered, the first one when halo…

Astrophysics of Galaxies · Physics 2015-06-23 Pedro Colin , Vladimir Avila-Reese , Alejandro Gonzalez-Samaniego , Hector Velazquez

We investigate the rms peculiar velocity of galaxy clusters in the Lambda cold dark matter ($\Lambda$CDM) and tau cold dark matter ($\tau$CDM) cosmological models using N-body simulations. Cluster velocities for different cluster masses and…

Astrophysics · Physics 2009-11-07 Ivan Suhhonenko , Mirt Gramann

We investigate the clustering of high redshift galaxies in five variants of the cold dark matter (CDM) scenario, using hydrodynamic cosmological simulations that resolve the formation of systems with circular velocities $v_c \geq 100 \kms$…

Astrophysics · Physics 2009-10-30 Neal Katz , Lars Hernquist , David H. Weinberg

We analyse parallel N-body simulations of three Cold Dark Matter (CDM) universes to study the abundance and clustering of galaxy clusters. The simulations cover a volume comparable to the forthcoming SDSS. We are able to make robust…

Astrophysics · Physics 2008-11-26 F. Governato , A. Babul , T. Quinn , P. Tozzi , C. M. Baugh , N. Katz , G. Lake

The abundance of galactic systems at high redshifts can impose a strong constraint on the cold+hot dark matter (CDM+HDM) models. The hot component reduces the excessive small-scale power in the COBE-normalized CDM model but also delays the…

Astrophysics · Physics 2009-10-22 Chung-Pei Ma , Edmund Bertschinger

We use high resolution dissipationless N-body simulations to examine the spatial distribution of galaxy clusters on large scales. The Standard CDM model and two of its main competitors, Low density CDM and Mixed Dark Matter are compared.The…

Astrophysics · Physics 2007-05-23 R. A. C. Croft , G. Efstathiou

The dynamics of the Local Group and its environment provide a unique challenge to cosmological models. The velocity field within 5h-1 Mpc of the Local Group (LG) is extremely ``cold''. The deviation from a pure Hubble flow, characterized by…

Astrophysics · Physics 2016-08-30 F. Governato , B. Moore , R. Cen , J. Stadel , G. Lake , T. Quinn

We use the void probability statistics to study the redshift-space galaxy distribution as described by a volume-limited subsample of the Perseus-Pisces survey. We compare the results with the same analysis realized on artificial samples,…

Astrophysics · Physics 2009-10-22 S. Ghigna , S. Borgani , S. Bonometto , L. Guzzo , A. Klypin , J. R. Primack , R. Giovanelli , M. Haynes

We investigate peculiar velocities predicted for clusters in Lambda cold dark matter ($\Lambda$CDM) models assuming that the initial density fluctuation field is Gaussian. To study the non-linear regime, we use N-body simulations. We…

Astrophysics · Physics 2007-05-23 Mirt Gramann , Ivan Suhhonenko

We report results from high-resolution particle-mesh (PM) N-body simulations of structure formation in an $\Omega=1$ cosmological model with a mixture of Cold plus Hot Dark Matter (C+HDM) having $\Omega_{\rm cold}=0.6$, $\Omega_\nu=0.3$,…

Astrophysics · Physics 2010-11-30 Anatoly Klypin , Jon Holtzman , Joel Primack , Eniko Regos

Using a set of $\pppm$ simulation which accurately treats the density evolution of two components of dark matter, we study the evolution of clusters in the Cold + Hot dark matter (CHDM) model. The mass function, the velocity dispersion…

Astrophysics · Physics 2009-10-22 Y. P. Jing , L. Z. Fang
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