{"title":"Halo Radius (Splashback Radius) of Groups and Clusters of Galaxies on Small Scales","authors":"F. G. Kopylova, A. I. Kopylov","doi":"10.1134/S199034132204006X","DOIUrl":null,"url":null,"abstract":"<div><div><p>We report the results of a study of the distribution of galaxies in the projection along the radius (<span>\\(R \\leqslant 3{{R}_{{200{\\text{c}}}}}\\)</span>) for 157 groups and clusters of galaxies in the local Universe (0.01 < <span>\\(z\\)</span> < 0.10) with line-of-sight velocity dispersions 200 < <span>\\(\\sigma \\)</span> < 1100 km s<sup>–1</sup>. We introduce a new observed boundary for the halos of clusters of galaxies, which we identify with the splashback radius <span>\\({{R}_{{{\\text{sp}}}}}\\)</span>. We also identified the core of groups/clusters of galaxies with the radius <span>\\({{R}_{{\\text{c}}}}\\)</span>. These radii are determined by the observed integrated distribution of the number of galaxies as a function of squared angular radius from the center of the group/cluster, which (usually) coincides with the brightest galaxy. We found for the entire sample that the boundary of dark matter <span>\\({{R}_{{{\\text{sp}}}}}\\)</span> for groups/clusters of galaxies is proportional to the radius <span>\\({{R}_{{{\\text{200}}}}}\\)</span> of the virialized region. We measured the mean radius <span>\\(\\langle {{R}_{{{\\text{sp}}}}}\\rangle = 1.14 \\pm 0.02\\)</span> Mpc for groups of galaxies (<span>\\(\\sigma \\leqslant 400\\)</span> km s<sup>–1</sup>) and <span>\\(\\langle {{R}_{{{\\text{sp}}}}}\\rangle = 2.00 \\pm 0.07\\)</span> Mpc for clusters of galaxies (<span>\\(\\sigma > 400\\)</span> km s<sup>–1</sup>). The mean ratio of radii is <span>\\(\\langle {{{{R}_{{{\\text{sp}}}}}} \\mathord{\\left/ {\\vphantom {{{{R}_{{{\\text{sp}}}}}} {{{R}_{{{\\text{200c}}}}}}}} \\right. \\kern-0em} {{{R}_{{{\\text{200c}}}}}}}\\rangle = 1.40 \\pm 0.02\\)</span>, or <span>\\(\\langle {{{{R}_{{{\\text{sp}}}}}} \\mathord{\\left/ {\\vphantom {{{{R}_{{{\\text{sp}}}}}} {{{R}_{{{\\text{200m}}}}}}}} \\right. \\kern-0em} {{{R}_{{{\\text{200m}}}}}}}\\rangle = 0.88 \\pm 0.02\\)</span>.</p></div></div>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":null,"pages":null},"PeriodicalIF":1.3000,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Astrophysical Bulletin","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1134/S199034132204006X","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
We report the results of a study of the distribution of galaxies in the projection along the radius (\(R \leqslant 3{{R}_{{200{\text{c}}}}}\)) for 157 groups and clusters of galaxies in the local Universe (0.01 < \(z\) < 0.10) with line-of-sight velocity dispersions 200 < \(\sigma \) < 1100 km s–1. We introduce a new observed boundary for the halos of clusters of galaxies, which we identify with the splashback radius \({{R}_{{{\text{sp}}}}}\). We also identified the core of groups/clusters of galaxies with the radius \({{R}_{{\text{c}}}}\). These radii are determined by the observed integrated distribution of the number of galaxies as a function of squared angular radius from the center of the group/cluster, which (usually) coincides with the brightest galaxy. We found for the entire sample that the boundary of dark matter \({{R}_{{{\text{sp}}}}}\) for groups/clusters of galaxies is proportional to the radius \({{R}_{{{\text{200}}}}}\) of the virialized region. We measured the mean radius \(\langle {{R}_{{{\text{sp}}}}}\rangle = 1.14 \pm 0.02\) Mpc for groups of galaxies (\(\sigma \leqslant 400\) km s–1) and \(\langle {{R}_{{{\text{sp}}}}}\rangle = 2.00 \pm 0.07\) Mpc for clusters of galaxies (\(\sigma > 400\) km s–1). The mean ratio of radii is \(\langle {{{{R}_{{{\text{sp}}}}}} \mathord{\left/ {\vphantom {{{{R}_{{{\text{sp}}}}}} {{{R}_{{{\text{200c}}}}}}}} \right. \kern-0em} {{{R}_{{{\text{200c}}}}}}}\rangle = 1.40 \pm 0.02\), or \(\langle {{{{R}_{{{\text{sp}}}}}} \mathord{\left/ {\vphantom {{{{R}_{{{\text{sp}}}}}} {{{R}_{{{\text{200m}}}}}}}} \right. \kern-0em} {{{R}_{{{\text{200m}}}}}}}\rangle = 0.88 \pm 0.02\).
期刊介绍:
Astrophysical Bulletin is an international peer reviewed journal that publishes the results of original research in various areas of modern astronomy and astrophysics, including observational and theoretical astrophysics, physics of the Sun, radio astronomy, stellar astronomy, extragalactic astronomy, cosmology, and astronomy methods and instrumentation.