Dark matter in the elliptical galaxy NGC 1407

1994 ◽  
Author(s):  
Raymond E. White ◽  
Victor Andersen ◽  
Chris Williamson
Keyword(s):  
Dark Matter ◽  
Elliptical Galaxy

scholarly journals A CENSUS OF BARYONS AND DARK MATTER IN AN ISOLATED, MILKY WAY SIZED ELLIPTICAL GALAXY

2011 ◽  
Vol 729 (1) ◽  
pp. 53 ◽  
Author(s):  
Philip J. Humphrey ◽  
David A. Buote ◽  
Claude R. Canizares ◽  
Andrew C. Fabian ◽  
Jon M. Miller
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Elliptical Galaxy

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 ChandraEvidence of a Flattened, Triaxial Dark Matter Halo in the Elliptical Galaxy NGC 720

2002 ◽  
Vol 577 (1) ◽  
pp. 183-196 ◽  
Author(s):  
David A. Buote ◽  
Tesla E. Jeltema ◽  
Claude R. Canizares ◽  
Gordon P. Garmire
Keyword(s):  
Dark Matter ◽  
Elliptical Galaxy ◽  
Dark Matter Halo

scholarly journals The coherent motion of Cen A dwarf satellite galaxies remains a challenge for ΛCDM cosmology

2021 ◽  
Vol 645 ◽  
pp. L5
Author(s):  
Oliver Müller ◽  
Marcel S. Pawlowski ◽  
Federico Lelli ◽  
Katja Fahrion ◽  
Marina Rejkuba ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Similar Case ◽  
Dwarf Galaxies ◽  
Elliptical Galaxy ◽  
Satellite System ◽  
Coherent Motion ◽  
Small Scale ◽  
Planar Structures ◽  
Scale Challenges

The plane-of-satellites problem is one of the most severe small-scale challenges for the standard Λ cold dark matter (ΛCDM) cosmological model: Several dwarf galaxies around the Milky Way and Andromeda co-orbit in thin, planar structures. A similar case has been identified around the nearby elliptical galaxy Centaurus A (Cen A). In this Letter, we study the satellite system of Cen A, adding twelve new galaxies with line-of-sight velocities from VLT/MUSE observations. We find that 21 out of 28 dwarf galaxies with measured velocities share a coherent motion. Similarly, flattened and coherently moving structures are found only in 0.2% of Cen A analogs in the Illustris-TNG100 cosmological simulation, independently of whether we use its dark-matter-only or hydrodynamical run. These analogs are not co-orbiting, and they arise only by chance projection, thus they are short-lived structures in such simulations. Our findings indicate that the observed co-rotating planes of satellites are a persistent challenge for ΛCDM, which is largely independent from baryon physics.

scholarly journals Shells and the Potential Wells of Elliptical Galaxies

1987 ◽  
Vol 127 ◽  
pp. 249-259
Author(s):  
P.J. Quinn ◽  
Lars Hernquist
Keyword(s):  
Dark Matter ◽  
Large Range ◽  
Elliptical Galaxy ◽  
Elliptical Galaxies ◽  
Potential Well ◽  
Potential Wells ◽  
Shell System ◽  
History Of

A survey of the possible variety of sharp-edged, caustic features that may arise in the collision of galaxies with very different masses and sizes (Hernquist and Quinn 1986a) has shown that in general shells are morphologically very complex. It is therefore not easy to determine the history of the collision that produced the shells nor the properties of the galaxies involved. However, a small number of shell galaxies (notably NGC 3923) have a sufficiently simple and orderly shell distribution that we believe the shells were formed by a chance very symmetric and simple encounter. In such cases we are presented with a unique opportunity to investigate the potential well of an elliptical galaxy over a large range in radius (≃ 0.5re − 20re). An analysis of the NGC 3923 shell system (Hernquist and Quinn 1986b) has shown that a large amount of dark matter is present (Mdark≃ 40Mluminous, r < 17re).

scholarly journals Unveiling the Influence of Dark Matter in Axially Symmetric Galaxies

2013 ◽  
Vol 30 ◽  
Author(s):  
Nicolaos D. Caranicolas ◽  
Euaggelos E. Zotos
Keyword(s):  
Dark Matter ◽  
Elliptical Galaxy ◽  
Equations Of Motion ◽  
Dark Matter Halo ◽  
Meridional Plane ◽  
Axially Symmetric ◽  
Indicator Method ◽  
Galactic Model ◽  
Fast Lyapunov Indicator ◽  
Regular And Chaotic Motion

AbstractWe investigate the regular or chaotic nature of orbits of stars moving in the meridional plane (R,z) of an axially symmetric galactic model with a dense, massive spherical nucleus and a dark matter halo component. In particular, we study the influence of the fractional portion of the dark matter, by computing in each case the percentage of chaotic orbits, as well as the percentages of orbits of the main regular resonant families. In an attempt to distinguish between regular and chaotic motion, we use the fast Lyapunov indicator method to extensive samples of orbits obtained by integrating numerically the equations of motion as well as the variational equations. Furthermore, a technique which is based mainly on the field of spectral dynamics that utilises the Fourier transform of the time series of each coordinate is used for identifying the various families of regular orbits and also to recognise the secondary resonances that bifurcate from them. Two cases are studied in our work: (i) the case where we have a disk galaxy model and (ii) the case where our model represents an elliptical galaxy. A comparison with early related work is also made.

scholarly journals THE DARK-MATTER FRACTION IN THE ELLIPTICAL GALAXY LENSING THE QUASAR PG 1115+080

2009 ◽  
Vol 697 (2) ◽  
pp. 1892-1900 ◽  
Author(s):  
D. Pooley ◽  
S. Rappaport ◽  
J. Blackburne ◽  
P. L. Schechter ◽  
J. Schwab ◽  
...  
Keyword(s):  
Dark Matter ◽  
Elliptical Galaxy

scholarly journals The HI-rich Elliptical Galaxy NGC 5266: An Old Merger Remnant?

1997 ◽  
Vol 14 (1) ◽  
pp. 89-91 ◽  
Author(s):  
R. Morganti ◽  
E. M. Sadler ◽  
T. A. Oosterloo ◽  
A. Pizzella ◽  
F. Bertola
Keyword(s):  
Dark Matter ◽  
Spiral Galaxies ◽  
Elliptical Galaxy ◽  
Neutral Hydrogen ◽  
Dark Matter Halo ◽  
Dust Lane ◽  
Neutral Gas

AbstractWe present HI images for the dust-lane elliptical galaxy NGC 5266. This galaxy contains more than 1010M☉ of HI and our data show that the neutral hydrogen extends to ∼8 arcmin each side of the nucleus, or eight times the optical half-light radius Re. Surprisingly, the outer HI gas extends almost orthogonally to the optical dust lane. The overall HI kinematics can be successfully modelled by assuming that the gas hes in two orthogonal planes—in the plane of the dust lane in the central parts and perpendicular to this in the outer regions. The large amount of neutral gas observed and the HI morphology suggest that this object may have formed from the merger of two gas rich spiral galaxies. If so, it probably represents a relatively old merger remnant since most of the HI appears settled. The mass-to-light ratio has also been derived, with evidence for a dark matter halo around this galaxy.

scholarly journals Dark matter deprivation in the field elliptical galaxy NGC 7507

2015 ◽  
Vol 574 ◽  
pp. A93 ◽  
Author(s):  
Richard R. Lane ◽  
Ricardo Salinas ◽  
Tom Richtler
Keyword(s):  
Dark Matter ◽  
Elliptical Galaxy
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