期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 415, 期 1, 页码 545-562出版社
OXFORD UNIV PRESS
DOI: 10.1111/j.1365-2966.2011.18725.x
关键词
galaxies: elliptical and lenticular, cD; galaxies: kinematics and dynamics; galaxies: structure
资金
- DFG [SFB 375]
- DFG Cluster of Excellence
- University of Padua [60A02-1283/10, CPDA089220]
- Ministry of Education, University, and Research [EARA 2004-2006]
- TR33 'The Dark Universe'
- Cluster of Excellence 'Origin and Structure of the Universe'
- Space Telescope Science Institute under NASA [NAS5-26555]
- Alfred P. Sloan Foundation
- National Science Foundation
- US Department of Energy
- NASA
- Japanese Monbukagakusho
- Max Planck Society
- Higher Education Funding Council for England
- American Museum of Natural History
- Astrophysical Institute Pots-dam
- University of Basel
- University of Cambridge
- Case Western Reserve University
- University of Chicago
- Drexel University
- Fermilab
- Institute for Advanced Study
- Japan Participation Group
- Johns Hopkins University
- Joint Institute for Nuclear Astrophysics
- Kavli Institute for Particle Astrophysics and Cosmology
- Korean Scientist Group
- Chinese Academy of Sciences (LAMOST)
- Los Alamos National Laboratory
- Max-Planck-Institute for Astronomy
- Max-Planck-Institute for Astrophysics
- New Mexico State University
- Ohio State University
- University of Pittsburgh
- University of Portsmouth
- Princeton University
- United States Naval Observatory
- University of Washington
- STFC [ST/I001204/1] Funding Source: UKRI
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [0908639] Funding Source: National Science Foundation
- Science and Technology Facilities Council [ST/I001204/1] Funding Source: researchfish
This work aims to study the distribution of the luminous and dark matter in Coma early-type galaxies. Dynamical masses obtained under the assumption that mass follows light do not match with the masses of strong gravitational lens systems of similar velocity dispersions. Instead, dynamical fits with dark matter haloes are in good agreement with lensing results. We derive mass-to-light ratios of the stellar populations from Lick absorption line indices, reproducing well the observed galaxy colours. Even in dynamical models with dark matter haloes the amount of mass that follows the light increases more rapidly with the galaxy velocity dispersion than expected for a constant stellar initial mass function (IMF). While galaxies around sigma(eff) approximate to 200 km s(-1) are consistent with a Kroupa IMF, the same IMF underpredicts luminous dynamical masses of galaxies with sigma(eff) approximate to 300 km s(-1) by a factor of 2 and more. A systematic variation in the stellar IMF with the galaxy velocity dispersion could explain this trend with a Salpeter IMF for the most massive galaxies. If the IMF is instead constant, then some of the dark matter in high-velocity-dispersion galaxies must follow a spatial distribution very similar to that of the light. A combination of both, a varying IMF and a component of dark matter that follows the light is possible as well. For a subsample of galaxies with old stellar populations, we show that the tilt in the Fundamental Plane can be explained by systematic variations of the total (stellar + dark) mass inside the effective radius. We tested commonly used mass estimator formulae, finding them accurate at the 20-30 per cent level.
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