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Dark-matter-only simulations predict that dark matter halos have cusp-like inner density profiles, while observations of low-mass galaxies have found a range of inner slopes that are typically much shallower. It is still not well…

We make the most precise determination to date of the number density of extragalactic 21-cm radio sources as a function of their spectral line widths - the HI velocity width function (HIWF) - based on 21827 sources from the final 7000…

Astrophysics of Galaxies · Physics 2021-11-17 Kyle A. Oman

We investigate the growth rate of structures in the local Universe. For this, we use as a cosmological tracer the HI line extra-galactic sources from the Arecibo Legacy Fast ALFA (ALFALFA) survey to obtain a measurement of the normalized…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-07 F. Avila , A. Bernui , E. de Carvalho , C. P. Novaes

Astrophysical observations indicate that the ``Local Universe" has a relatively lower matter density ($\Omega_0$) than the predictions of the standard inflation cosmology and the large-scale motions of galaxies which provide a mean mass…

Astrophysics · Physics 2016-08-30 Xiang-Ping Wu , Zugan Deng , Zhenlong Zou , Li-Zhi Fang , Bo Qin

We employ a bias-corrected abundance matching technique to investigate the coevolution of the LCDM dark halo mass function (HMF), the observationally derived velocity dispersion and stellar mass functions (VDF, SMF) of galaxies between z=1…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Kyu-Hyun Chae

We present the first results from the new Bolshoi N-body cosmological LCDM simulation that uses cosmological parameters favored by current observations. The Bolshoi simulation was done in a volume 250Mpc on a side using 8billion particles…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 A. Klypin , S. Trujillo-Gomez , J. Primack

The spherical infall model first developed by Lema\^{i}tre and Tolman was modified in order to include the effects of a dark energy term. The resulting velocity-distance relation was evaluated numerically. This equation, when fitted to…

Astrophysics · Physics 2016-08-16 Sébastien Peirani , José Antonio De Freitas Pacheco

N-body simulations were conducted of pairs of galaxies with a 3:1 mass ratio on parabolic orbits, in order to quantify the effect of dynamical friction. The effects of varying the ratio of the dark matter halo size to the distance of…

Astrophysics · Physics 2016-08-30 Roger E. Bartlett , Jane C. Charlton

We compare the half-light circular velocities, V_{1/2}, of dwarf galaxies in the Local Group to the predicted circular velocity curves of galaxies in the NIHAO suite of LCDM simulations. We use a subset of 34 simulations in which the…

Astrophysics of Galaxies · Physics 2016-01-20 Aaron A. Dutton , Andrea V. Macciò , Jonas Frings , Liang Wang , Gregory S. Stinson , Camilla Penzo , Xi Kang

We use a high resolution $\Lambda$CDM numerical simulation to calculate the mass function of dark matter haloes down to the scale of dwarf galaxies, back to a redshift of fifteen, in a 50 $h^{-1}$Mpc volume containing 80 million particles.…

The Universe expansion rate is modulated around local inhomogeneities due to their gravitational potential. Velocity waves are then observed around galaxy clusters in the Hubble diagram. This paper studies them in a ~738 Mpc wide, with…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-30 Jenny G. Sorce , Roya Mohayaee , Nabila Aghanim , Klaus Dolag , Nicola Malavasi

The non-linear, scale-dependent bias in the mass distribution of galaxies and the underlying dark matter is a key systematic affecting the extraction of cosmological parameters from galaxy clustering. Using 95 million halos from the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Elise Jennings , Carlton M. Baugh , Dylan Hatt

We present a new approach for quantifying the abundance of galaxy clusters and constraining cosmological parameters using dynamical measurements. In the standard method, galaxy line-of-sight (LOS) velocities, $v$, or velocity dispersions…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-25 M. Ntampaka , H. Trac , J. Cisewski , L. C. Price

In an attempt to place an explicit constraint on dark matter models, we define and estimate a mean surface density of a dark halo within a radius of maximum circular velocity, which is derivable for various galaxies with any dark-matter…

Astrophysics of Galaxies · Physics 2015-06-24 Kohei Hayashi , Masashi Chiba

We use a complete set of deep narrow-band imaging data for 384 galaxies gathered during the VESTIGE survey to derive the first Halpha luminosity function (LF) of the Virgo cluster within R200. The data allow us to cover the whole dynamic…

We introduce a set of high-resolution dissipationless simulations that model the Local Group (LG) in a cosmological context: Exploring the Local Volume in Simulations (ELVIS). The suite contains 48 Galaxy-size halos, each within…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-16 Shea Garrison-Kimmel , Michael Boylan-Kolchin , James Bullock , Kyle Lee

We combine data from a number of N-body simulations to predict the abundance of dark halos in Cold Dark Matter universes over more than 4 orders of magnitude in mass. A comparison of different simulations suggests that the dominant…

We use Fabry-Perot Halpha spectroscopy, complemented with published HI radio synthesis observations to derive high resolution rotation curves of spiral galaxies. We investigate precisely their inner mass distribution and compare it to CDM…

Astrophysics · Physics 2007-05-23 Sebastien Blais-Ouellette , Claude Carignan , Philippe Amram

We study the local dark matter velocity distribution in simulated Milky Way-mass galaxies, generated at high resolution with both dark matter and baryons. We find that the dark matter in the Solar neighborhood is influenced appreciably by…

Astrophysics of Galaxies · Physics 2016-11-09 Jonathan D. Sloane , Matthew R. Buckley , Alyson M. Brooks , Fabio Governato

We study the implications of galaxy formation on dark matter direct detection using high resolution hydrodynamic simulations of Milky Way-like galaxies simulated within the EAGLE and APOSTLE projects. We identify Milky Way analogues that…