Free Access
Issue
Astron. Astrophys. Suppl. Ser.
Volume 144, Number 1, May II 2000
Page(s) 53 - 84
DOI https://doi.org/10.1051/aas:2000199
Published online 15 May 2000
DOI: 10.1051/aas:2000199

Astron. Astrophys. Suppl. Ser. 144, 53-84

Orbital structure and mass distribution in elliptical galaxies

Andi Kronawitter 1 - R.P. Saglia 2[*] - Ortwin Gerhard 1 - Ralf Bender 2

Send offprint request: A. Kronawitter e-mail: krona@astro.unibas.ch


1 - Astronomisches Institut, Universität Basel, Venusstrasse 7, CH-4102 Binningen, Switzerland
2 - Institut für Astronomie und Astrophysik, Scheinerstraße 1, D-81679 Munich, Germany

Received December 23, 1999; accepted February 15, 2000

Abstract:

We report on a homogeneous dynamical analysis of a sample of 21 round (17 E0/E1, 4 E2) elliptical galaxies. We present new kinematic data for eight of these galaxies and new photometry for one object. The remaining kinematic and photometric data and the required distance information are taken from the literature. The analysis uses non-parametric spherical models and takes into account line profile information as well as velocity dispersions. We present model fits to the kinematic data and the derived radial profiles of orbital anisotropy and B-band mass-to-light ratio, including confidence intervals. The circular velocity curves resulting from our model fits are all consistent with being flat outside $R\approx 0.3
R_{\rm e}$. Generally, the M/L ratio profiles show an outward increase, although models based on luminous matter are ruled out at 95% confidence only for three galaxies (NGC 2434, NGC 7507, NGC 7626). For NGC 1399, NGC 4472, NGC 4486, and NGC 4636, where X-ray observations are available, the mass profiles of the best fit models match the ones derived from the X-ray analysis. The best models for most galaxies are isotropic to slightly radially anisotropic, with typical $\beta\mathrel{\mathchoice {\vcenter{\offinterlineskip\halign{\hfil
$\displaysty...
...\offinterlineskip\halign{\hfil$\scriptscriptstyle ..., in a few cases $\beta\mathrel{\mathchoice {\vcenter{\offinterlineskip\halign{\hfil
$\displaysty...
...\offinterlineskip\halign{\hfil$\scriptscriptstyle ... at $R_{\rm e}/2$. We discuss the generally small effects of flattening along the line-of-sight (the expected $\!<c/a\!>$ = 0.79 for this sample of luminous ellipticals) and of small embedded disks. Our results suggest that elliptical galaxies have surprisingly uniform dynamical properties.

Key words: galaxies: elliptical and lenticular, cD -- galaxies: fundamental parameters, kinematics and dynamics, photometry, structure

SIMBAD Objects
Tables at the CDS

Copyright The European Southern Observatory (ESO)

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.