On Escaping a Galaxy Cluster in an Accelerating Universe
- Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Astronomy
- Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Astronomy and Dept. of Physics
We derive the escape velocity profile for an Einasto density field in an accelerating universe and demonstrate its physical viability by comparing theoretical expectations to both light-cone data generated from N-body simulations and archival data on 20 galaxy clusters. We demonstrate that the projection function ($$g(\beta)$$) is deemed physically viable only for the theoretical expectation that includes a cosmology-dependent term. Using simulations, we show that the inferred velocity anisotropy is more than 6σ away from the expected value for the theoretical profile that ignores the acceleration of the universe. In the archival data, we constrain the average velocity anisotropy parameter of a sample of 20 clusters to be $$\beta ={0.248}_{-0.360}^{+0.164}$$ at the 68% confidence level. Finally, we briefly discuss how our analytic model may be used as a novel cosmological probe based on galaxy clusters.
- Research Organization:
- Univ. of Michigan, Ann Arbor, MI (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Science Foundation (NSF)
- Contributing Organization:
- German Astrophysical Virtual Observatory (GAVO); Univ. of Strasbourg (France). Strasbourg Astronomical Data Center (CDS) and VizieR Service for Astronomical Catalogues
- Grant/Contract Number:
- SC0013520; 1311820; 1256260
- OSTI ID:
- 1473889
- Journal Information:
- The Astrophysical Journal (Online), Vol. 830, Issue 2; ISSN 1538-4357
- Publisher:
- Institute of Physics (IOP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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