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We study the stellar mass function (SMF) and the co-evolution with dark matter halos via abundance matching in the largest redshift range to date $0.2<z<12$ in $0.53 \, {\rm deg}^2$ imaged by JWST from the COSMOS-Web survey. At $z>5$, we…

We study the density profile and shape of the Galactic halo using deep multicolour images from the MENeaCS and CCCP projects, over 33 fields selected to avoid overlap with the Galactic plane. Using multicolour selection and PSF…

星系天体物理 · 物理学 2015-06-24 B. Pila-Díez , J. T. A. de Jong , K. Kuijken , R. F. J. van der Burg , H. Hoekstra

The observed flaring of HI disk in the outer region of galaxies has been used in the past to determine the shape of the dark matter halo. Previous studies based on this concept suggest a slightly oblate halo (axis ratio ~ 0.8) for our…

天体物理学 · 物理学 2009-11-11 C. A. Narayan , K. Saha , C. J. Jog

Dark matter (DM) halos of Sc-Im and dwarf spheroidal (dSph) galaxies satisfy scaling laws: halos in lower-luminosity galaxies have smaller core radii, higher central densities, and smaller velocity dispersions. These results are based on…

星系天体物理 · 物理学 2016-02-17 John Kormendy , K. C. Freeman

Dynamical modeling and strong lensing data indicate that the total density profiles of early-type galaxies are close to isothermal, i.e., rho_tot ~ r^gamma with gamma approx -2. To understand the origin of this universal slope we study a…

I review the up-to-date status on the properties of the Dark Matter density distribution around Galaxies. The rotation curves of spirals all conform to a same Universal profile which can be uniquely decomposed as the sum of an exponential…

天体物理学 · 物理学 2007-05-23 Paolo Salucci

The properties of galaxies are intricately linked to the characteristics of their host dark-matter haloes. We use a suite of controlled simulations of isolated galaxies to quantify how halo spin, concentration, inner density profile, and…

星系天体物理 · 物理学 2026-05-28 Guangze Sun , Fangzhou Jiang , Jing Wang

Using data from the Sloan Digital Sky Survey Early Data Release and SuperCOSMOS Sky Survey scans of POSS-I plates we identify a sample of 2600 subdwarfs using reduced proper motion methods and strict selection criteria. This forms one of…

天体物理学 · 物理学 2008-11-26 Andrew P. Digby , Nigel C. Hambly , John A. Cooke , I. Neill Reid , Russell D. Cannon

The cold dark matter halo mass function is much steeper than the galaxy stellar mass function on galactic and subgalactic scales. This difference is usually reconciled by assuming that the galaxy formation efficiency drops sharply with…

宇宙学与河外天体物理 · 物理学 2015-06-03 Ismael Ferrero , Mario G. Abadi , Julio F. Navarro , Laura V. Sales , Sebastian Gurovich

We examine correlations between the masses, sizes, and star formation histories for a large sample of low-redshift early-type galaxies, using a simple suite of dynamical and stellar populations models. We confirm an anti-correlation between…

宇宙学与河外天体物理 · 物理学 2015-05-18 Nicola R. Napolitano , Aaron J. Romanowsky , Crescenzo Tortora

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…

星系天体物理 · 物理学 2019-08-14 Magdelena Allen , Peter Behroozi , Chung-Pei Ma

We introduce a mass dependent density profile to describe the distribution of dark matter within galaxies, which takes into account the stellar-to-halo mass dependence of the response of dark matter to baryonic processes. The study is based…

宇宙学与河外天体物理 · 物理学 2015-06-19 Arianna Di Cintio , Chris B. Brook , Aaron A. Dutton , Andrea V. Macciò , Greg S. Stinson , Alexander Knebe

Observations of (B-V) colour distributions towards the galactic poles are compared with those obtained from synthetic colour-magnitude diagrams to determine the major constituents in the disc and spheroid. The disc is described with four…

天体物理学 · 物理学 2009-06-16 Y. K. Ng , G. Bertelli , C. Chiosi , A. Bressan

Recent observations suggest the existence of a white dwarf population in the Galactic halo, while others suggest that deuterium has been astrated in systems at high redshift and low metallicity. We propose that these observations could be…

天体物理学 · 物理学 2009-09-15 Brian D. Fields , Keith A. Olive , Joseph Silk , Michel Casse , Elisabeth Vangioni-Flam

The stellar-mass--halo-mass (SMHM) relation is central to our understanding of galaxy formation and the nature of dark matter. However, its normalisation, slope, and scatter are highly uncertain at dwarf galaxy scales. In this paper, we…

Accurate synthetic models of stellar populations are constructed and used in evolutionary models of stellar populations in forming galaxies. Following their formation, the late type galaxies are assumed to follow the Schmidt law for star…

天体物理学 · 物理学 2009-10-30 R. Jimenez , A. Kashlinsky

Precise abundance ratios are determined for 94 dwarf stars with 5200 < Teff < 6300 K, -1.6 < [Fe/H] < -0.4, and distances D < 335 pc. Most of them have halo kinematics, but 16 thick-disk stars are included. Equivalent widths of atomic lines…

星系天体物理 · 物理学 2015-05-18 Poul E. Nissen , William J. Schuster

Large numbers of low-to-medium resolution spectra of M-type dwarf stars from both the local Galactic disk and halo are available from various surveys. In order to fully exploit these data, we develop a template-fit method using a set of…

太阳与恒星天体物理 · 物理学 2020-03-11 Neda Hejazi , Sebastien Lepine , Derek Homeier , R. Michael Rich , Michael M. Shara

Deep galaxy counts are among the best constraints on the cosmic star formation history (SFH) of galaxies. The evolution of the star formation activity is followed on a wide range of redshifts (0< z < 4) covering most of the history of the…

天体物理学 · 物理学 2009-10-31 Brigitte Rocca-Volmerange , Michel Fioc

We study the stellar haloes of galaxies out to 70-100 kpc as a function of stellar mass and galaxy type by stacking aligned $r$ and $g$ band images from a sample of 45508 galaxies from SDSS DR9 in the redshift range $0.06\,\le\,z\,\le\,0.1$…

星系天体物理 · 物理学 2015-06-19 R. D'Souza , G. Kauffmann , J. Wang , S. Vegetti