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We simulate the dynamical and chemical evolution of a dwarf galaxy embedded in a dark matter halo, using a three-dimensional N-body/SPH simulation code combined with stellar population synthesis. The initial condition is adopted in accord…

天体物理学 · 物理学 2016-08-30 Masao Mori , Yuzuru Yoshii , Takuji Tsujimoto , Ken'ichi Nomoto

The abundance of faint dwarf galaxies is determined by the underlying population of low-mass dark matter (DM) halos and the efficiency of galaxy formation in these systems. Here, we quantify potential galaxy formation and DM constraints…

We analyze 166 spheroid subdwarfs $(6.5<M_V<14.5)$ found in 53 fields observed with the Wide Field Camera on the {\it Hubble Space Telescope}. The fields cover 221 square arcmin over a wide range of directions. The spheroid luminosity…

天体物理学 · 物理学 2009-10-30 Andrew Gould , Chris Flynn , John N. Bahcall

Using the Galactica code of Benson et al., we obtain quantitative measurements of spheroid-to-disk ratios for a sample of 8839 galaxies observed in the Sloan Digital Sky Survey. We carry out extensive tests of this code and of Gim2D,…

天体物理学 · 物理学 2008-11-26 A. J. Benson , Dajana Dzanovic , C. S. Frenk , Ray Sharples

The virial theorem prescribes the ratio of the globally-averaged equatorial to vertical velocity dispersion of a tracer population in spherical and flattened dark haloes. This gives sequences of physical models in the plane of global…

星系天体物理 · 物理学 2015-06-03 A. Agnello , N. W. Evans

We build on a recent photometric decomposition analysis of 7506 Galaxy and Mass Assembly (GAMA) survey galaxies to derive stellar mass function fits to individual spheroid and disk component populations down to a lower mass limit of…

We study properties of dark matter halos at high redshifts z=2-10 for a vast range of masses with the emphasis on dwarf halos with masses 10^7-10^9 Msun/h. We find that the density profiles of relaxed dwarf halos are well fitted by the NFW…

天体物理学 · 物理学 2009-11-10 P. Colin , A. Klypin , O. Valenzuela , S. Gottlober

Mergers and the spin of the dark matter halo are factors traditionally believed to determine the morphology of galaxies within a $\Lambda$CDM cosmology. We study this hypothesis by considering approximately 18,000 central galaxies at $z=0$…

In this paper, we extend the calculations conducted previously in the stellar regime to determine the brown dwarf IMF in the Galactic disk. We perform Monte Carlo calculations taking into account the brown dwarf formation rate, spatial…

天体物理学 · 物理学 2010-04-21 G. Chabrier

We develop a method for recovering the global density distribution of the ancient Galactic stellar halo prior to disk formation, based on the present orbits of metal-poor stars observed in the solar neighborhood. The method relies on the…

天体物理学 · 物理学 2009-10-31 Masashi Chiba , Timothy C. Beers

I review current efforts to measure the mean density of dark matter near the Sun. This encodes valuable dynamical information about our Galaxy and is also of great importance for 'direct detection' dark matter experiments. I discuss…

星系天体物理 · 物理学 2014-06-16 J. I. Read

The star formation rate density (SFRD) is an important tool in galaxy evolution that allows us to identify at which cosmic time galaxies are more efficient at forming stars. For low-mass star-forming galaxies, the SFRD as a function of…

星系天体物理 · 物理学 2025-04-07 G. G. Murrell , I. K. Baldry

Recent discoveries of optical signatures of black holes in dwarf galaxies indicates that low-mass galaxies can indeed host intermediate massive black holes. This motivates the assessment of the resulting effect on the host dark matter…

高能天体物理现象 · 物理学 2015-06-19 Alma X. Gonzalez-Morales , Stefano Profumo , Farinaldo S. Queiroz

Fitting Galactic structure models to star counts only provides useful information about the Galaxy in some directions. In this paper, we investigate the use of $\chi^2$ goodness-of-fit tests to discriminate between degenerate Galactic…

天体物理学 · 物理学 2009-10-31 Hiranya V. Peiris

We present the results of a study of weak lensing by galaxies based on 45.5 deg$^2$ of $R_C$ band imaging data from the Red-Sequence Cluster Survey (RCS). We present the first weak lensing detection of the flattening of galaxy dark matter…

天体物理学 · 物理学 2008-11-26 Henk Hoekstra , Howard K. C. Yee , Michael D. Gladders

I present a new Galactic chemical evolution model motivated by and grounded in the hierarchical theory of galaxy formation, as expressed by a halo merger history of the Galaxy. This model accurately reproduces the "metallicity distribution…

天体物理学 · 物理学 2009-11-13 Jason Tumlinson

We investigate in massive early-type galaxies the variation of their two-dimensional central fraction of dark over total mass and dark matter density as a function of stellar mass, central stellar velocity dispersion, effective radius, and…

宇宙学与河外天体物理 · 物理学 2015-05-19 Claudio Grillo

We analyze the star formation history (SFH) of galaxies as a function of present-day environment, galaxy stellar mass and morphology. The SFH is derived by means of a non-parametric spectrophotometric model applied to individual galaxies at…

The kinematics of stars and planetary nebulae in early type galaxies provide vital clues to the enigmatic physics of their dark matter halos. We fit published data for fourteen such galaxies using a spherical, self-gravitating model with…

宇宙学与河外天体物理 · 物理学 2015-05-18 Curtis J. Saxton , Ignacio Ferreras

We investigate how a property of a galaxy correlates most tightly with a property of its host dark matter halo, using state-of-the-art hydrodynamical simulations of galaxy formation EAGLE, Illustris, and IllustrisTNG. Unlike most of the…

宇宙学与河外天体物理 · 物理学 2020-03-11 Jian-hua He