A substantial population of low-mass stars in luminous elliptical galaxies

  title={A substantial population of low-mass stars in luminous elliptical galaxies},
  author={Pieter van Dokkum and Charlie Conroy},
The stellar initial mass function (IMF) describes the mass distribution of stars at the time of their formation and is of fundamental importance for many areas of astrophysics. The IMF is reasonably well constrained in the disk of the Milky Way but we have very little direct information on the form of the IMF in other galaxies and at earlier cosmic epochs. Here we report observations of the Na i doublet and the Wing–Ford molecular FeH band in the spectra of elliptical galaxies. These lines are… Expand
Systematic variation of the stellar initial mass function in early-type galaxies
A study of the two-dimensional stellar kinematics for the large representative ATLAS3D sample of nearby early- type galaxies spanning two orders of magnitude in stellar mass, using detailed dynamical models finds a strong systematic variation in IMF in early-type galaxies as a function of their stellar mass-to-light ratios, implying that a galaxy’s IMF depends intimately on the galaxy's formation history. Expand
The Stellar Initial Mass Function in Early-Type Galaxies from Absorption Line Spectroscopy. III. Radial Gradients
There is good evidence that the centers of massive early-type galaxies have a bottom-heavy stellar initial mass function (IMF) compared to the IMF of the Milky Way. Here we study the radial variationExpand
The initial mass function of a massive relic galaxy
Massive relic galaxies formed the bulk of their stellar component before z � 2 and have remained unaltered since then. Therefore, they represent a unique opportunity to study in great detail theExpand
The IMF-SFH connection in massive early-type galaxies
The stellar initial mass function (IMF) is one of the fundamental pillars in studies of stellar populations. It is the mass distribution of stars at birth, and it is traditionally assumed to beExpand
Radial variations in the stellar initial mass function of early-type galaxies
The hypothesis of a universal initial mass function (IMF) -- motivated by observations in nearby stellar systems -- has been recently challenged by the discovery of a systematic variation of the IMFExpand
The galaxy-wide initial mass function of dwarf late-type to massive early-type galaxies
Observational studies are showing that the galaxy-wide stellar initial mass function are top-heavy in galaxies with high star-formation rates (SFRs). Calculating the integrated galactic stellarExpand
Astrophysics: Stars throw their weight in old galaxies
A survey of a mass-selected sample of 260 early galaxies reveals systematic variation in stellar initial mass function, and suggests that models assuming a constant IMF need to be revised to explain how stars seem to sense what kind of galaxy they are creating. Expand
The stellar mass function and efficiency of galaxy formation with a varying initial mass function
Several recent observational studies have concluded that the initial mass function (IMF) of stars varies systematically with galaxy properties such as velocity dispersion. In this paper, weExpand
The stellar populations of massive galaxies in the local Universe
  • R. McDermid
  • Physics
  • Proceedings of the International Astronomical Union
  • 2012
Abstract I present a brief review of the stellar population properties of massive galaxies, focusing on early-type galaxies in particular, with emphasis on recent results from the ATLAS3D Survey. IExpand
Strong gravitational lensing and the stellar IMF of early-type galaxies
Systematic variations of the initial mass function (IMF) in early-type galaxies, and their connection with possible drivers such as velocity dispersion or metallicity, have been much debated inExpand


Evidence of Cosmic Evolution of the Stellar Initial Mass Function
Theoretical arguments and indirect observational evidence suggest that the stellar IMF may evolve with time, such that it is more weighted toward high-mass stars at higher redshift. Here we test thisExpand
On the evolutionary history of stars and their fossil mass and light
The total extragalactic background radiation can be an important test of the global star formation history (SFH). Using direct observational estimates of the SFH, along with standard assumptionsExpand
Formation of Early-Type Galaxies from Cosmological Initial Conditions
We describe high-resolution smoothed particle hydrodynamics (SPH) simulations of three approximately M* field galaxies starting from ΛCDM initial conditions. The simulations are made intentionallyExpand
Can the faint submillimetre galaxies be explained in the Λ cold dark matter model
We present predictions for the abundance of submillimetre galaxies (SMGs) and Lyman-break galaxies (LBGs) in the Λ cold dark matter cosmology. A key feature of our model is the self-consistentExpand
The Stellar Population Histories of Local Early-Type Galaxies. I. Population Parameters
This paper commences a series of investigations into the stellar populations of local elliptical galaxies as determined from their integrated spectra. The goal of the series is to determine the starExpand
The Low-Mass Stellar Content of Galaxies: Constraints through Hybrid Population Synthesis near 1 Micron
We present high signal-to-noise observations obtained with the RC spectrograph at the CTIO 4 m telescope of six galaxies and of a variety of dwarfs and galactic bulge giants in the 9800-10200 AExpand
Accurate masses of very low mass stars: IV Improved mass-luminosity relations
We present improved visual and near-infrared empirical mass-luminosity relations for very low mass stars (M$<$0.6~\Msol). These relations make use of all stellar masses in this range known withExpand
The Epochs of Early-Type Galaxy Formation as a Function of Environment
The aim of this paper is to set constraints on the epochs of early-type galaxy formation through the archaeology of the stellar populations in local galaxies. Using our models of absorption-lineExpand
On the variation of the initial mass function
A universal initial mass function (IMF) is not intuitive, but so far no convincing evidence for a variable IMF exists. The detection of systematic variations of the IMF with star-forming conditionsExpand
The Initial Mass Function of Early-Type Galaxies
We determine an absolute calibration of the initial mass function (IMF) of early-type galaxies, by studying a sample of 56 gravitational lenses identified by the Sloan Lenses ACS Survey. Under theExpand