Dark matter in elliptical galaxies

1995 ◽  
Author(s):  
Francesco Bertola ◽  
Alessandro Pizzella
Keyword(s):  
Dark Matter ◽  
Elliptical Galaxies

Dark Matter in Elliptical Galaxies

1989 ◽  
pp. 431-432
Author(s):  
R. P. Saglia ◽  
G. Bertin ◽  
M. Stiavelli
Keyword(s):  
Dark Matter ◽  
Elliptical Galaxies

scholarly journals Mass Distribution of the E0 Galaxy NGC 6703 from Absorption Line Profile Kinematics

1999 ◽  
Vol 186 ◽  
pp. 189-190
Author(s):  
O.E. Gerhard ◽  
G. Jeske ◽  
R.P. Saglia ◽  
Ralf Bender
Keyword(s):  
Dark Matter ◽  
Absorption Line ◽  
Mass Distribution ◽  
Line Profile ◽  
Elliptical Galaxies ◽  
Velocity Profiles ◽  
Matter Content ◽  
Orbit Structure ◽  
Extensive Analysis ◽  
Preliminary Account

Absorption line velocity profiles (vps) contain important information on the anisotropy and mass distribution of elliptical galaxies (e.g., Gerhard 1993, Merritt 1993). Here we briefly present results of an extensive analysis of the E0 galaxy NGC 6703 (Gerhard et al. 1997). This work is part of an observational and theoretical program aimed at understanding the orbit structure and dark matter content of ellipticals at intermediate radii (a preliminary account is given in Saglia et al. 1997).

Evidence against baryonic dark matter in elliptical galaxies

1989 ◽  
Vol 346 ◽  
pp. 648 ◽  
Author(s):  
Dennis J. Hegyi ◽  
Keith A. Olive
Keyword(s):  
Dark Matter ◽  
Elliptical Galaxies ◽  
Baryonic Dark Matter

Dark Matter Halos in Elliptical Galaxies

1993 ◽  
Vol 416 ◽  
pp. L45 ◽  
Author(s):  
Francesco Bertola ◽  
Alessandro Pizzella ◽  
Massimo Persic ◽  
Paolo Salucci
Keyword(s):  
Dark Matter ◽  
Elliptical Galaxies ◽  
Dark Matter Halos

scholarly journals A Model for the Sequence of Elliptical Galaxies

1987 ◽  
Vol 117 ◽  
pp. 367-367
Author(s):  
Rosemary F. G. Wyse ◽  
Bernard J. T. Jones
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Initial Conditions ◽  
Elliptical Galaxy ◽  
Elliptical Galaxies ◽  
Density Fluctuations ◽  
Analytic Approximation ◽  
Non Linear

We present a simple model for the formation of elliptical galaxies, based on a binary clustering hierarchy of dark matter, the chemical enrichment of the gas at each level being controlled by supernovae. The initial conditions for the non-linear phases of galaxy formation are set by the post-recombination power spectrum of density fluctuations. We investigate two models for this power spectrum - the first is a straightforward power law, |δk|2 ∝ kn, and the second is Peeble's analytic approximation to the emergent spectrum in a universe dominated by cold dark matter. The normalisation is chosen such that on some scale, say M ∼ 1012M⊙, the objects that condense out have properties - radius and velocity dispersion - resembling ‘typical’ galaxies. There is some ambiguity in this due to the poorly determined mass-to-light ratio of a typical elliptical galaxy — we look at two normalisations, σ1D ∼ 350kms−1 and σ1D ∼ 140kms−1. The choice determines which of Compton cooling or hydrogen cooling is more important during the galaxy formation period. The non-linear behaviour of the perturbations is treated by the homogeneous sphere approximation.

scholarly journals The Tilt of the Fundamental Plane of Elliptical Galaxies: Dynamical and Structural Effects

1996 ◽  
Vol 171 ◽  
pp. 403-403
Author(s):  
B. Lanzoni ◽  
L. Ciotti ◽  
A. Renzini
Keyword(s):  
Dark Matter ◽  
Velocity Dispersion ◽  
Elliptical Galaxies ◽  
Stellar Mass ◽  
Fine Tuning ◽  
Structural Effects ◽  
Fundamental Plane ◽  
Systematic Trend ◽  
Radial Anisotropy ◽  
Light Profiles

We explore several structural and dynamical effects on the projected velocity dispersion as possible causes of the fundamental plane (FP) tilt of elliptical galaxies (Ciotti, Lanzoni & Renzini, 1995). Specifically, we determine the size of the systematic trend along the FP in the orbital radial anisotropy, in the dark matter (DM) content and distribution relative to the bright matter, and in the shape of the light profile that would be needed to produce the tilt, under the assumption of a constant stellar mass to light ratio. Spherical, non rotating, two-components models are constructed, where the light profiles resemble the R1/4 law. For these we can exclude orbital anisotropy as the origin of the tilt, while a systematic increase in the DM content and/or concentration may formally produce it. Also a suitable variation of the light profile can produce the desired effect, and there may be some observational hints supporting this possibility. However, fine tuning is always required in order to reproduce the tilt, while preserving the tightness of the galaxies distribution about the FP.

Dark Matter: Abstracts from a Two-day Workshop held in February 1994 by the Australia Telescope National Facility

1995 ◽  
Vol 12 (1) ◽  
pp. 117-138
Author(s):  
Bärbel Koribalski
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Elliptical Galaxies

Summary A Dark Matter Workshop was held at the CSIRO Radiophysics Laboratory in Marsfield, Sydney, on 24–25 February 1994. The workshop, sponsored by the Australia Telescope National Facility (ATNF), was a meeting of dark matter (DM) specialists as well as astronomers interested in the field, and attracted about 80 participants from nine institutions. The program consisted of 22 oral contributions (15–45 minutes), followed by lively discussions, as well as podium discussions at the end of each day. Abstracts of most of the contributions are presented here, arranged by subject groups which range from ‘Gravitational Lensing and DM in Clusters’, ‘DM in Elliptical Galaxies’, ‘The Nature of DM’, and ‘The Shapes of Dark Halos’ to ‘Alternatives to DM’.

scholarly journals Universal relations with fermionic dark matter

2018 ◽  
Vol 168 ◽  
pp. 04015
Author(s):  
A. Krut ◽  
C. R. Argüelles ◽  
J. A. Rueda ◽  
R. Ruffini
Keyword(s):  
Dark Matter ◽  
Finite Size ◽  
Elliptical Galaxies ◽  
Compact Objects ◽  
Space Distribution ◽  
Fermion Mass ◽  
Fermion Masses ◽  
Natural Mechanism ◽  
First Time ◽  
Good Agreement

We have recently introduced a new model for the distribution of dark matter (DM) in galaxies, the Ruffini-Argüelles-Rueda (RAR) model, based on a self-gravitating system of massive fermions at finite temperatures. The RAR model, for fermion masses above keV, successfully describes the DM halos in galaxies, and predicts the existence of a denser quantum core towards the center of each configuration. We demonstrate here, for the first time, that the introduction of a cutoff in the fermion phase-space distribution, necessary to account for galaxies finite size and mass, defines a new solution with a compact quantum core which represents an alternative to the central black hole (BH) scenario for SgrA*. For a fermion mass in the range 48keV ≤ mc2 ≤ 345keV, the DM halo distribution fulfills the most recent data of the Milky Way rotation curves while harbors a dense quantum core of 4×106M⊙ within the S2 star pericenter. In particular, for a fermion mass of mc2 ∼ 50keV the model is able to explain the DM halos from typical dwarf spheroidal to normal elliptical galaxies, while harboring dark and massive compact objects from ∼ 103M⊙ tp to 108M⊙ at their respective centers. The model is shown to be in good agreement with different observationally inferred universal relations, such as the ones connecting DM halos with supermassive dark central objects. Finally, the model provides a natural mechanism for the formation of supermassive BHs as heavy as few ∼ 108M⊙. We argue that larger BH masses (few ∼ 109−10M⊙) may be achieved by assuming subsequent accretion processes onto the above heavy seeds, depending on accretion efficiency and environment.

Interplay between Dark Matter and Galactic Structure in Disk and Oblate Elliptical Galaxies

2014 ◽  
Vol 35 (4) ◽  
pp. 649-673
Author(s):  
Euaggelos E. Zotos ◽  
Nicolaos D. Caranicolas
Keyword(s):  
Dark Matter ◽  
Elliptical Galaxies ◽  
Galactic Structure
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