The relative concentration of visible and dark matter in clusters of galaxies

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

13 pages, 3 figures, accepted for publication in Il Nuovo Cimento B

Scientific paper

10.1393/ncb/i2008-10506-x

[Abridged] We consider two clusters (A496 and Coma) that are representative of the two classes of cool-core and non-cool-core clusters. We first refer to a two-component dynamical model that ignores the contribution from the galaxy density distribution and study the condition of hydrostatic equilibrium for the hot intracluster medium (ICM) under the assumption of spherical symmetry, in the presence of dark matter. We model the ICM density distribution in terms of a standard $\beta$-model with $\beta=2/3$, i.e. with a distribution similar to that of a regular isothermal sphere (RIS), and fit the observed X-ray brightness profiles. With the explicit purpose of ignoring cosmological arguments, we na\"ively assume that dark matter, if present, has an analogous density distribution, with the freedom of two different density and length scales. The relative distribution of visible and dark matter is then derived by fitting the temperature data for the ICM under conditions of hydrostatic equilibrium. For both clusters, we find that dark matter is more concentrated with respect to visible matter. We then test whether the conclusion changes significantly when dark matter is taken to be distributed according to cosmologically favored density profiles and when the contribution of the mass contained in galaxies is taken into account. Although the qualitative conclusions remain unchanged, we find that the contribution of galaxies to the mass budget is more important than generally assumed. We also show that, without resorting to additional information on the small scale, it is not possible to tell whether a density cusp is present or absent in these systems. [Abridged]

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

The relative concentration of visible and dark matter in clusters of galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The relative concentration of visible and dark matter in clusters of galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The relative concentration of visible and dark matter in clusters of galaxies will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-208690

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.