The dark outside: the density profile of dark matter haloes beyond the virial radius

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

12 pages, 10 figures, submitted for publication in MNRAS

Scientific paper

We present an approximation for the average density profile of dark matter haloes in the LambdaCDM cosmological model, which is accurate to within 10--15% even for large radial distances from 0.05R_{vir} up to 10R_{vir} for halo masses ranging from 10^{11.5} to 10^{15.0} h^{-1}M_{Sun}. We propose a modified form of the Navarro, Frenk & White (NFW) approximation: \rho(r)=\rho_{NFW}(r)+ A (r/R_{vir})^{-1}+B (1+r/R_{vir})^{-1}. This generalized expression, which is applicable to the external regions of dark matter haloes, only very slightly affects the density in the inner regions of haloes. The strong correlation among the different parameters in the model allows us to describe the profile in terms of just one parameter: the virial mass. We integrate our density profile to derive the enclosed mass in a sphere of a given radius and compare it with the NFW results. We find that the NFW underestimates the enclosed mass by more than 50% at 10R_{vir}, whereas our model reproduces the results from numerical simulations to within 2% accuracy even at this distance. We also use this new approximation to study the weak gravitational lensing and to obtain an analytic expression for the tangential shear. This allows us to quantify the contribution to the shear from the outer regions of the density profile. For the first time we calculate the difference between the tangential shear calculated via the NFW profile and the corresponding result when the external regions of haloes in cosmological simulations are taken into account. We find a 4% difference for all the mass ranges under study.

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 dark outside: the density profile of dark matter haloes beyond the virial radius 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 dark outside: the density profile of dark matter haloes beyond the virial radius, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The dark outside: the density profile of dark matter haloes beyond the virial radius will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-388749

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