相关论文: The velocity function in the local environment fro…
The ongoing Arecibo Legacy Fast ALFA (ALFALFA) survey is a wide-area, extragalactic HI-line survey conducted at the Arecibo Observatory. Sources have so far been extracted over ~3,000 sq.deg of sky (40% of its final area), resulting in the…
The circular velocity function (CVF) of galaxies is a fundamental test of the $\Lambda$ Cold Dark Matter (CDM) paradigm as it traces the variation of galaxy number densities with circular velocity ($v_{\rm{circ}}$), a proxy for dynamical…
The velocity function derived from large scale surveys can be compared with the predictions of LCDM cosmology, by matching the measured rotation velocities Vrot of galaxies to the maximum circular velocity of dark matter (DM) halos Vmax.…
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…
Current explanation of the overabundance of dark matter subhalos in the Local Group (LG) indicates that there maybe a limit on mass of a halo, which can host a galaxy. This idea can be tested using voids in the distribution of galaxies: at…
It has long been regarded as difficult for a cosmological model to account simultaneously for the galaxy luminosity, mass, and velocity distributions. We revisit this issue using a modern compilation of observational data along with the…
Current explanation of the overabundance of dark matter subhalos in the Local Group (LG) indicates that there maybe a limit on mass of a halo, which can host a galaxy. This idea can be tested using voids in the distribution of galaxies: at…
We used 87 high resolution hydrodynamical cosmological simulations from the NIHAO suite to investigate the relation between the maximum circular velocity (Vmax) of a dark matter halo in a collisionless simulation and the velocity width of…
Using high-resolution simulations within the Cold and Warm Dark Matter models we study the evolution of small scale structure in the Local Volume, a sphere of 8 Mpc radius around the Local Group. We compare the observed spectrum of…
We measure the mass function of dark matter halos in a large set of collisionless cosmological simulations of flat LCDM cosmology and investigate its evolution at z<~2. Halos are identified as isolated density peaks, and their masses are…
We use N-body simulations to study the velocity bias of dark matter halos, the difference in the velocity fields of dark matter and halos, in a flat low- density LCDM model. The high force, 2kpc/h, and mass, 10^9Msun/h, resolution allows…
We use 85 pairs of high resolution LCDM cosmological simulations from the NIHAO project to investigate why in dwarf galaxies neutral hydrogen (HI) linewidths measured at 50% of the peak flux W_50 /2 (from the hydrodynamical simulations)…
We use the high-resolution Aquarius cosmological dark matter simulations coupled to the semi-analytic model by Starkenburg et al. (2013) to study the HI content and velocity width properties of field galaxies at the low mass end in the…
Using numerical simulations and the Sheth-Tormen approximation we study the mass function of dark matter halos in voids. We find that the void mass function is significantly lower and its shape is different than that of the field halos. We…
We investigate the evolution in the dark matter halo circular velocity function, measured at a fixed physical radius of 20 kpc (v_20), which is likely to be a good proxy for galaxy circular velocity, in the Millennium-II simulation. We find…
We give a summary of our recent studies of spatial and velocity biases of galaxy-size halos in cosmological models. Recent progress in numerical techniques made it possible to simulate halos in large volumes with a such accuracy that halos…
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…
Within a Lambda Cold Dark Matter (LCDM) scenario, we use high resolution cosmological simulations spanning over four orders of magnitude in galaxy mass to understand the deficit of dwarf galaxies in observed velocity functions. We measure…
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…
Accurately predicting the shape of the HI velocity function of galaxies is regarded widely as a fundamental test of any viable dark matter model. Straightforward analyses of cosmological $N$-body simulations imply that the $\Lambda$CDM…