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We explore the environmental dependence of star formation timescales in low mass galaxies using the [$\alpha$/Fe] abundance ratio as an evolutionary clock. We present integrated [$\alpha$/Fe] measurements for 11 low mass ($M_\star \sim…

A number of recent studies have proposed that the stellar initial mass function (IMF) of early type galaxies varies systematically as a function of galaxy mass, with higher mass galaxies having bottom heavy IMFs. These bottom heavy IMFs…

We conduct a detailed investigation of the properties of the stellar initial mass function (IMF) in two massive early-type lens galaxies with velocity dispersions of sigma ~245 km/s and sigma ~325 km/s, for which both HST imaging and…

宇宙学与河外天体物理 · 物理学 2015-06-16 Matteo Barnabè , Chiara Spiniello , Léon V. E. Koopmans , Scott C. Trager , Oliver Czoske , Tommaso Treu

We use spiral galaxy evolution models to argue that there are substantial variations in stellar mass-to-light ratio (M/L) within and among galaxies. Our models show a strong correlation between stellar M/L and galaxy color. We compare the…

天体物理学 · 物理学 2007-05-23 Roelof S. de Jong , Eric F. Bell

Few topics in astronomy initiate such vigorous discussion as whether or not the initial mass function (IMF) of stars is universal, or instead sensitive to the initial conditions of star formation. The distinction is of critical importance:…

星系天体物理 · 物理学 2015-05-18 Nate Bastian , Kevin R. Covey , Michael R. Meyer

We study the behaviour of the dynamical and stellar mass inside the effective radius (re) of early-type galaxies (ETGs). We use several samples of ETGs -ranging from 19 000 to 98 000 objects- from the ninth data release of the Sloan Digital…

We derive a semi-empirical galactic initial mass function (IMF) from observational constraints. We assume that the star formation rate in a galaxy can be expressed as the product of the IMF, $\psi (m)$, which is a smooth function of mass…

星系天体物理 · 物理学 2015-05-20 Antonio Parravano , Christopher F. McKee , David J. Hollenbach

The stellar initial mass function (IMF) is thought to be bottom-heavy in the cores of the most massive galaxies, with an excess of low mass stars compared to the Milky Way. However, studies of the kinematics of quiescent galaxies at 2<z<5…

星系天体物理 · 物理学 2024-09-10 Pieter van Dokkum , Charlie Conroy

Over the past years observations of young and populous star clusters have shown that the stellar initial mass function (IMF) can be conveniently described by a two-part power-law with an exponent alpha_2 = 2.3 for stars more massive than…

星系天体物理 · 物理学 2010-11-10 Carsten Weidner , Jan Pflamm-Altenburg , Pavel Kroupa

One of the most robust observations of the stellar initial mass function (IMF) is its near-universality in the Milky Way and neighboring galaxies. But recent observations of early-type galaxies can be interpreted to imply a bottom-heavy…

星系天体物理 · 物理学 2019-03-26 David Guszejnov , Philip F. Hopkins , Andrew S. Graus

We review recent determinations of the present day and initial mass functions in various components of the Galaxy, disk, spheroid, young and globular clusters. As a general feature, the IMF is well described by a power-law form for $m\ga 1…

天体物理学 · 物理学 2008-11-26 Gilles Chabrier

We derive the average mass profile of elliptical galaxies from the ensemble of 161 strong gravitational lens systems selected from several surveys, assuming that the mass profile scales with the stellar mass and effective radius of each…

宇宙学与河外天体物理 · 物理学 2015-06-17 Masamune Oguri , Cristian E. Rusu , Emilio E. Falco

We investigate the most plausible stellar Initial Mass Function (IMF) and the main origin of the tilt of the Fundamental Plane (FP) for old, massive early-type galaxies. We consider a sample of 13 bright galaxies of the Coma cluster and…

宇宙学与河外天体物理 · 物理学 2015-05-14 C. Grillo , R. Gobat

Low-mass stars (M<0.4Msun) are thought to comprise the bulk of the stellar mass of galaxies but they constitute only of order a percent of the bolometric luminosity of an old stellar population. Directly estimating the number of low-mass…

宇宙学与河外天体物理 · 物理学 2015-05-30 Charlie Conroy , Pieter van Dokkum

Based on MUSE integral-field data we present evidence for a radial variation at the low-mass end of the stellar initial-mass function (IMF) in the central regions of the giant early-type galaxy NGC4486 (M87). We used state-of-the-art…

星系天体物理 · 物理学 2018-05-16 Marc Sarzi , Chiara Spiniello , Francesco La Barbera , Davor Krajnović , Remco van den Bosch

We obtain constraints on the slope of a universal stellar initial mass function (IMF) over a range of cosmic star-formation histories (SFH) using z=0.1 luminosity densities in the range from 0.2 to 2.2 microns. The age-IMF degeneracy of…

天体物理学 · 物理学 2011-05-05 I. K. Baldry , K. Glazebrook

(abridged) The case can be made for a rather universal stellar IMF form that can be approximated by a two-part power-law function in the stellar regime. However, there exists a possible hint for a systematic variation with metallicity. A…

天体物理学 · 物理学 2007-05-23 Pavel Kroupa

The evolution of the galaxy stellar mass--star formation rate relationship (M*-SFR) provides key constraints on the stellar mass assembly histories of galaxies. For star-forming galaxies, M*-SFR is observed to be fairly tight with a slope…

天体物理学 · 物理学 2010-11-23 Romeel Davé

We investigate the spatially resolved stellar populations of a sample of seven nearby massive Early-type galaxies (ETGs), using optical and near infrared data, including K-band spectroscopy. This data offers good prospects for mitigating…

星系天体物理 · 物理学 2018-05-23 P. D. Alton , R. J. Smith , J. R. Lucey