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We derive an accurate mass estimator for dispersion-supported stellar systems and demonstrate its validity by analyzing resolved line-of-sight velocity data for globular clusters, dwarf galaxies, and elliptical galaxies. Specifically, by…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Joe Wolf , Gregory D. Martinez , James S. Bullock , Manoj Kaplinghat , Marla Geha , Ricardo R. Munoz , Joshua D. Simon , Frank F. Avedo

Determining the dynamical mass profiles of dispersion-supported galaxies is particularly challenging due to projection effects and the unknown shape of their velocity anisotropy profile. Our goal is to develop a machine learning algorithm…

Using collisionless N-body simulations of dwarf galaxies orbiting the Milky Way (MW) we construct realistic models of dwarf spheroidal (dSph) galaxies of the Local Group. The dwarfs are initially composed of stellar disks embedded in dark…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Klaudia Kowalczyk , Ewa L. Lokas , Stelios Kazantzidis , Lucio Mayer

We use a suite of high-resolution cosmological dwarf galaxy simulations to test the accuracy of commonly-used mass estimators from Walker et al.(2009) and Wolf et al.(2010), both of which depend on the observed line-of-sight velocity…

Starting with the spherical Jeans equation, we show that there exists a radius where the mass enclosed depends only on the projected tangential velocity dispersion, assuming that the anisotropy profile slowly varies. This is…

Astrophysics of Galaxies · Physics 2020-03-25 Alexandres Lazar , James S. Bullock

We compare the performance of mass estimators for elliptical galaxies that rely on the directly observable surface brightness and velocity dispersion profiles, without invoking computationally expensive detailed modeling. These methods…

Astrophysics of Galaxies · Physics 2015-05-27 N. Lyskova , J. Thomas , E. Churazov , S. Tremaine , T. Naab

By manipulating the spherical Jeans equation, Wolf et al. (2010) show that the mass enclosed within the 3D deprojected half-light radius r_1/2 can be determined with only mild assumptions about the spatial variation of the stellar velocity…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Joe Wolf

We investigate the reliability of mass estimators based on the observable velocity dispersion and half-light radius $R_\mathrm{h}$ for dispersion-supported galaxies. We show how to extend them to flattened systems and provide simple…

Astrophysics of Galaxies · Physics 2016-10-19 Jason L. Sanders , N. Wyn Evans

We introduce a method for measuring the slopes of mass profiles within dwarf spheroidal (dSph) galaxies directly from stellar spectroscopic data and without adopting a dark matter halo model. Our method combines two recent results: 1)…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Matthew G. Walker , Jorge Peñarrubia

Using a set of 73 numerically simulated galaxy clusters, we have characterised the statistical and physical biases for three velocity dispersion and mass estimators, namely biweight, gapper and standard deviation, in the small number of…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-12 Antonio Ferragamo , José Alberto Rubiño-Martín , Juan Betancort-Rijo , Emiliano Munari , Barbara Sartoris , Rafael Barrena

Forthcoming large-scale spectroscopic surveys will soon provide data on thousands of galaxy clusters. It is important that the systematics of the various mass estimation techniques are well understood and calibrated. We compare three…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-07 Thomas J. Armitage , Scott T. Kay , David J. Barnes , Yannick M. Bahé , Claudio Dalla Vecchia

Assuming spherical symmetry and dynamical equilibrium within a given gravitational potential, a dwarf spheroidal (dSph) galaxy's globally averaged stellar velocity dispersion depends entirely on the shape of its stellar density profile.…

Astrophysics of Galaxies · Physics 2026-02-13 Sofia L. Splawska , Raphaël Errani , Jorge Peñarrubia , Matthew G. Walker

We present the results of a study that uses numerical simulations to interpret observations of tidally disturbed satellites around the Milky Way. When analysing the simulations from the viewpoint of an observer, we find a break in the slope…

Astrophysics · Physics 2009-10-30 Kathryn V. Johnston , Steinn Sigurdsson , Lars Hernquist

In this empirical work, we aim to quantify the systematic uncertainties in stellar mass $(M_\star)$ estimates made from spectral energy distribution (SED) fitting through stellar population synthesis (SPS), for galaxies in the local…

The purpose of this letter is to compare the quality of different methods for estimating stellar masses of galaxies. We compare the results of (a) fitting stellar population synthesis models to broad band colors from SDSS and 2MASS, (b) the…

Astrophysics · Physics 2009-11-10 N. Drory , R. Bender , U. Hopp

We measure the distribution of velocity dispersions of groups of galaxies identified in the UZC catalog; we use the distribution to derive the group mass function. We introduce a new method which makes efficient use of the entire magnitude…

Astrophysics · Physics 2009-11-10 Armando Pisani , Massimo Ramella , Margaret J. Geller

We show that different stellar-mass estimation methods yield overall mass scales that disagree by factors up to ~2 for the z=0 galaxy population, and more importantly, relative mass scales that sometimes disagree by factors >~3 between…

Astrophysics · Physics 2009-11-13 Sheila J. Kannappan , Eric Gawiser

We address the problem that dynamical masses of high-redshift massive galaxies, derived using virial scaling, often come out lower than stellar masses inferred from population fitting to multi-band photometry. We compare dynamical and…

Astrophysics of Galaxies · Physics 2015-08-10 Luis Peralta de Arriba , Marc Balcells , Jesús Falcón-Barroso , Ignacio Trujillo

We study dynamical models for elliptical galaxies, deriving the projected kinematic profiles in a form that is valid for general surface-brightness profiles and (spherical) total mass profiles, without the need for any explicit…

Astrophysics of Galaxies · Physics 2015-06-18 A. Agnello , N. W. Evans , A. J. Romanowsky

The accuracy and robustness of a simple method to estimate the total mass profile of a galaxy is tested using a sample of 65 cosmological zoom-simulations of individual galaxies. The method only requires information on the optical surface…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 N. Lyskova , E. Churazov , I. Zhuravleva , T. Naab , L. Oser , O. Gerhard , X. Wu
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