The inner structure of CDM haloes -- I. A numerical convergence study

Clicks: 3
ID: 302139
2003
Free PDF
Article Quality & Performance Metrics
Overall Quality
Not rated
Combines reader engagement with the AI quality analysis. This article has not been analysed, so there is no overall score — reader engagement is measured and shown alongside.
AI Quality Assessment
Not analyzed
Readership in this journal
Steady

Ranked #239 of 908 articles by views in monthly notices of the royal astronomical society

Most read Least read

Bar heights use a square-root scale. Only the 120 most-read articles are drawn; the journal has 908 in total.

Mint this article as an NFT
Not yet minted

Create a permanent, verifiable on-chain record of this article on the Scimatic Network. The NFT is held in your Journament account, and you can withdraw it to your own wallet at any time.

5 SUSD one-off · no wallet required
Sign in to mint
Abstract
We present a comprehensive set of convergence tests which explore the role of various numerical parameters on the equilibrium structure of a simulated dark matter halo. We report on results obtained with two independent, state-of-the-art, multi-stepping, parallel N-body codes: pkdgrav and gadget. We find that convergent mass profiles can be obtained for suitable choices of the gravitational softening, time-step, force accuracy, initial redshift, and particle number. For softenings chosen so that particle discreteness effects are negligible, convergence in the circular velocity is obtained at radii where the following conditions are satisfied: (i) the time-step is much shorter than the local orbital time-scale; (ii) accelerations do not exceed a characteristic acceleration imprinted by the gravitational softening; and (iii) enough particles are enclosed so that the collisional relaxation time-scale is longer than the age of the Universe. Convergence also requires sufficiently high initial redshift and accurate force computations. Poor spatial, time, or force resolution leads generally to systems with artificially low central density, but may also result in the formation of artificially dense central cusps. We have explored several adaptive time-stepping choices and we have obtained the best results when individual time-steps are chosen according to the local acceleration and the gravitational softening (Δti∝ (ε/ai)1/2), although further experimentation may yield better and more efficient criteria. The most stringent requirement for convergence is typically that imposed on the particle number by the collisional relaxation criterion. This implies that, in order to estimate accurate circular velocities at radii where the density contrast may reach ∼106, the region must enclose of the order of 3000 particles (or more than a few times 106 within the virial radius). Applying these criteria to a galaxy-sized ΛCDM halo, we find that the spherically averaged density profile becomes progressively shallower from the virial radius inwards, reaching a logarithmic slope shallower than −1.2 at the innermost resolved point, ∼0.005 r200, with little evidence for convergence to a power-law behaviour in the inner regions.
Reference Key
openalex_W2043137394 Use this key to autocite in the manuscript while using SciMatic Manuscript Manager or Thesis Manager
Authors Chris Power, Julio F. Navarro, Adrian Jenkins, Carlos S. Frenk, Simon D. M. White, Volker Springel, Joachim Stadel, Thomas Quinn
Journal monthly notices of the royal astronomical society
Year 2003
DOI
10.1046/j.1365-8711.2003.05925.x
URL
https://academic.oup.com/mnras/article-pdf/338/1/14/3823514/338-1-14.pdf
Keywords Keywords not found

Citations

No citations found. To add a citation, contact the admin at info@scimatic.org

Comments

No comments yet. Be the first to comment on this article.