The velocity fields of elliptical galaxies: constraints on intrinsic shapes
نویسندگان
چکیده
منابع مشابه
Intrinsic Shapes of Elliptical Galaxies
Tests for the intrinsic shape of the luminosity distribution in elliptical galaxies are discussed, with an emphasis on the uncertainties. Recent determinations of the ellipticity frequency function imply a paucity of nearly spherical galaxies, and may be inconsistent with the oblate hypothesis. Statistical tests based on the correlation of surface brightness, isophotal twisting, and minor axis ...
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In this paper we investigate the relation between the detailed isophotal shape of elliptical galaxies and the strength of the Hβ absorption in their spectra. We find that disky galaxies have higher Hβ indices. Stellar population synthesis models show that the Hβ line is a good age indicator, hence disky galaxies tend to have younger mean ages than boxy galaxies. We show that the observed trend ...
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Hubble Space Telescope (HST) observations reveal that the density of stars in most elliptical galaxies rises toward the center in a power-law cusp. Many of these galaxies also contain central dark objects, possibly supermassive black holes. The gravitational force from a steep cusp or black hole will destroy most of the box orbits that constitute the " backbone " of a triaxial stellar system. D...
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Using semi-analytical models of galaxy formation, the origin of boxy and disky elliptical galaxies is investigated. We find that the simple scenario, motivated by N-body simulations, in which the isophotal shape is only dependent on the mass ratio of the last major merger, is not able to reproduce the observation that the fraction of boxy and disky ellipticals depends on galaxy luminosity. The ...
متن کاملStrong lensing constraints on the velocity dispersion and density profile of elliptical galaxies
We use the statistics of strong gravitational lensing from the JVAS/CLASS survey to impose constraints on the velocity dispersion and density profile of elliptical galaxies. This approach differs from much recent work, where the luminosity function, velocity dispersion and density profile were typically assumed in order to constrain cosmological parameters. It is indeed remarkable that observat...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1993
ISSN: 0074-1809
DOI: 10.1017/s0074180900123940