Visible and dark matter in M 31 - II. A dynamical model and dark matter density distribution

Details Visible and dark matter in M 31 - II. A dynamical model and dark matter density distribution Visible and dark matter in M 31 - II. A dynamical model and dark matter density distribution

2007-07-30

arxiv.org/abs/0707.4374v2

Astronomy and Astrophysics

Astrophysics

12 pages, 13 figures

Scientific paper

In the present paper we derive the density distribution of dark matter (DM) in a well-observed nearby disc galaxy, the Andromeda galaxy. From photometrical and chemical evolution models constructed in the first part of the study (Tamm, Tempel & Tenjes 2007 (arXiv:0707.4375), hereafter Paper I) we can calculate the mass distribution of visible components (the bulge, the disc, the stellar halo, the outer diffuse stellar halo). In the dynamical model we calculate stellar rotation velocities along the major axis and velocity dispersions along the major, minor and intermediate axes of the galaxy assuming triaxial velocity dispersion ellipsoid. Comparing the calculated values with the collected observational data, we find the amount of DM, which must be added to reach an agreement with the observed rotation and dispersion data. We conclude that within the uncertainties, the DM distributions by Moore, Burkert, Navarro, Frenk & White (NFW) and the Einasto fit with observations nearly at all distances. The NFW and Einasto density distributions give the best fit with observations. The total mass of M 31 with the NFW DM distribution is 1.19*10^12 M_sun, the ratio of the DM mass to the visible mass is 10.0. For the Einasto DM distribution, these values are 1.28*10^12 M_sun and 10.8. The ratio of the DM mass to the visible mass inside the Holmberg radius is 1.75 for the NFW and the Einasto distributions. For different cuspy DM distributions, the virial mass is in a range 6.9-7.9*10^11 M_sun and the virial radius is ~150 kpc. The DM mean densities inside 10 pc for cusped models are 33 and 16 M_sun pc^-3 for the NFW and the Einasto profiles, respectively. For the cored Burkert profile, this value is 0.06 M_sun pc^-3.

Affiliated with

Also associated with

No associations

Rating

Visible and dark matter in M 31 - II. A dynamical model and dark matter density distribution 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 Visible and dark matter in M 31 - II. A dynamical model and dark matter density distribution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Visible and dark matter in M 31 - II. A dynamical model and dark matter density distribution will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-359338