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Title: On Escaping a Galaxy Cluster in an Accelerating Universe

Abstract

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.

Authors:
 [1];  [2];  [1]
  1. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Astronomy
  2. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Astronomy and Dept. of Physics
Publication Date:
Research Org.:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF)
Contributing Org.:
German Astrophysical Virtual Observatory (GAVO); Univ. of Strasbourg (France). Strasbourg Astronomical Data Center (CDS) and VizieR Service for Astronomical Catalogues
OSTI Identifier:
1473889
Grant/Contract Number:  
SC0013520; 1311820; 1256260
Resource Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 830; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; cosmology; galaxies; clusters

Citation Formats

Stark, Alejo, Miller, Christopher J., and Gifford, Daniel. On Escaping a Galaxy Cluster in an Accelerating Universe. United States: N. p., 2016. Web. doi:10.3847/0004-637X/830/2/109.
Stark, Alejo, Miller, Christopher J., & Gifford, Daniel. On Escaping a Galaxy Cluster in an Accelerating Universe. United States. https://doi.org/10.3847/0004-637X/830/2/109
Stark, Alejo, Miller, Christopher J., and Gifford, Daniel. Mon . "On Escaping a Galaxy Cluster in an Accelerating Universe". United States. https://doi.org/10.3847/0004-637X/830/2/109. https://www.osti.gov/servlets/purl/1473889.
@article{osti_1473889,
title = {On Escaping a Galaxy Cluster in an Accelerating Universe},
author = {Stark, Alejo and Miller, Christopher J. and Gifford, Daniel},
abstractNote = {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.},
doi = {10.3847/0004-637X/830/2/109},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 830,
place = {United States},
year = {Mon Oct 17 00:00:00 EDT 2016},
month = {Mon Oct 17 00:00:00 EDT 2016}
}

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