相关论文: Halo Mass Function: Low-mass Stars in Deep Fields

We use numerical simulations to examine the substructure within galactic and cluster mass halos that form within a hierarchical universe. Clusters are easily reproduced with a steep mass spectrum of thousands of substructure clumps that…

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…

Using deep images from the Hyper Suprime-Cam (HSC) survey and taking advantage of its unprecedented weak lensing capabilities, we reveal a remarkably tight connection between the stellar mass distribution of massive central galaxies and…

Some of the first stars could be cooler and more massive than standard stellar models would suggest, due to the effects of dark matter annihilation in their cores. It has recently been argued that such objects may attain masses in the…

We have searched the Forth Catalogue of Nearby Stars for halo stars and identified 15 subdwarfs and a high velocity white dwarf in the solar neighbourhood. This search was motivated mainly by the recent determinations of MACHO masses of…

Since z~1, the stellar mass density locked in low mass groups and clusters has grown by a factor of ~8. Here we make the first statistical measurements of the stellar mass content of low mass X-ray groups at 0.5<z<1, enabling the…

We have combined deep starcount data with Galaxy model predictions to investigate how effectively such measurements probe the faint end of the halo luminosity function. We have tested a number of star/galaxy classification techniques using…

In hierarchical galaxy formation the stellar halos of galaxies are formed by the accretion of minor satellites and therefore contain valuable information about the (early) assembly process of galaxies. Our GHOSTS survey measures the stellar…

We report on a search for long duration microlensing events towards the Large Magellanic Cloud. We find none, and therefore put limits on the contribution of high mass objects to the Galactic dark matter. At 95% confidence level we exclude…

We study the stellar halo color properties of six nearby massive highly inclined disk galaxies using Hubble Space Telescope Advanced Camera for Surveys and Wide Field Camera 3 observations in both F606W and F814W filters from the GHOSTS…

Disk-halo models of the Galaxy and LMC are constructed and used to analyse the microlensing data-set. Deflectors in the LMC bar, disk and halo provide an optical depth to microlensing of $\sim 2 \times 10^{-7}$. Deflectors in the Galactic…

We report on new measurements of the luminosity function (LF) and mass function (MF) of field low-mass dwarfs derived from Sloan Digital Sky Survey (SDSS) Data Release 6 (DR6) photometry. The analysis incorporates ~15 million low-mass stars…

Magnetic fields on a range of scales play a large role in the ecosystems of galaxies, both in the galactic disk and in the extended layers of gas away from the plane. Observing magnetic field strength, structure and orientation is complex,…

A decade ago, there was very limited knowledge of magnetic fields of our Galaxy. The local fields in the Solar vicinity were known to be directed towards a Galactic longitude $l\sim~90^{\circ}$ with reversed directions at smaller…

For any assumed stellar Initial Mass Function, the Sloan Digital Sky Survey (SDSS) gives a precise determination of the stellar mass function of galaxies for 10^8 M_sun < M_* < 10^12 M_sun. Within the concordance LCDM cosmology, the…

Stellar mass has been shown to correlate with halo mass, with non-negligible scatter. The stellar mass-size and luminosity-size relationships of galaxies also show significant scatter in galaxy size at fixed stellar mass. It is possible…

First galaxies formed within halos of mass M=E7.5-E9 Msun at z=30-40 in the standard cold dark matter (CDM) universe may each display an extended hydrogen 21-cm absorption halo against the cosmic microwave background with a brightness…

The simplest interpretation of the microlensing events observed towards the Large Magellanic Cloud is that approximately half of the mass of the Milky Way halo is in the form of MAssive Compact Halo Objects with $M \sim 0.5 M_{\odot}$. This…

We establish constraints on the mass and abundance of black holes in the Galactic halo by determining their impact on globular clusters which are conventionally considered to be little evolved. Using detailed Monte Carlo simulations and…

Most galaxies are hosted by massive, invisible dark matter haloes, yet little is known about the scatter in the stellar mass--halo mass relation for galaxies with host halo masses $M_{h}\le 10^{11}M_{\odot}$. Using mock catalogues based on…