期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 411, 期 3, 页码 1435-1444出版社
OXFORD UNIV PRESS
DOI: 10.1111/j.1365-2966.2010.17768.x
关键词
galaxies: elliptical and lenticular, cD; galaxies: evolution; galaxies: formation; galaxies: high-redshift
资金
- NASA [ADP/NNX09AD02G]
- European Community [MEXT-CT-2006-042754]
- Alfred P. Sloan Foundation
- National Science Foundation
- US Department of Energy
- National Aeronautics and Space Administration
- Japanese Monbukagakusho
- Max Planck Society
- Higher Education Funding Council for England
- American Museum of Natural History
- Astrophysical Institute Potsdam
- University of Basel
- University of Cambridge
- Case Western Reserve University
- The University of Chicago
- Drexel University
- Fermilab
- Institute for Advanced Study
- Japan Participation Group
- The 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 (MPIA)
- Max-Planck-Institute for Astrophysics (MPA)
- New Mexico State University
- Ohio State University
- University of Pittsburgh
- University of Portsmouth
- Princeton University
- United States Naval Observatory
- University of Washington
- Science and Technology Facilities Council [ST/F002335/1] Funding Source: researchfish
- STFC [ST/F002335/1] Funding Source: UKRI
We analyse a sample of 23 supermassive elliptical galaxies (central velocity dispersion larger than 330 km s(-1)) drawn from the Sloan Digital Sky Survey. For each object, we estimate the dynamical mass from the light profile and central velocity dispersion, and compare it with the stellar mass derived from stellar population models. We show that these galaxies are dominated by luminous matter within the radius for which the velocity dispersion is measured. We find that the sizes and stellar masses are tightly correlated, with R-e proportional to M-*(1.1), making the mean density within the de Vaucouleurs radius a steeply declining function of M-*: rho(e) proportional to M-*(-2.2). These scalings are easily derived from the virial theorem if one recalls that this sample has essentially fixed (but large) sigma(0). In contrast, the mean density within 1 kpc is almost independent of M*, at a value that is in good agreement with recent studies of z similar to 2 galaxies. The fact that the mass within 1 kpc has remained approximately unchanged suggests assembly histories that were dominated by minor mergers - but we discuss why this is not the unique way to achieve this. Moreover, the total stellar mass of the objects in our sample is typically a factor of similar to 5 larger than that in the high-redshift (z similar to 2) sample, an amount which seems difficult to achieve. If our galaxies are the evolved objects of the recent high-redshift studies, then we suggest that major mergers are required at z greater than or similar to 1.5 and that minor mergers become the dominant growth mechanism for massive galaxies at z less than or similar to 1.5.
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