Shapes of clusters and groups of galaxies

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dc.contributor.authorPaz, DJ
dc.contributor.authorLambas, DG
dc.contributor.authorPadilla, N
dc.contributor.authorMerchán, M
dc.date.accessioned2025-01-21T01:06:18Z
dc.date.available2025-01-21T01:06:18Z
dc.date.issued2006
dc.description.abstractWe study the properties of the three-dimensional and projected shapes of haloes using high-resolution numerical simulations and observational data where the latter comes from the 2PIGG [2dFGRS (2-degree Field Galaxy Redshift Survey) Percolation Inferred Galaxy Groups] and Data Release 3 of the Sloan Digital Sky Survey (SDSS-DR3GC) group catalogues. We investigate the dependence of the halo shape on characteristics such as mass and number of members. In the three-dimensional case, we find a significant correlation between the mass and the halo shape; massive systems are more prolate than small haloes. We detect a source of strong systematics in estimates of the triaxiality of a halo, which is found to be a strong function of the number of members; Lambda cold dark matter haloes usually characterized by triaxial shapes, slightly bent towards prolate forms, appear more oblate when taking only a small subset of the halo particles.
dc.description.abstractThe ellipticities of observed 2PIGG and SDSS-DR3GC groups are found to be strongly dependent on the number of group members, so that poor groups appear more elongated than rich ones. However, this is again an artefact caused by poor statistics and not an intrinsic property of the galaxy groups, nor an effect from observational biases. We interpret these results with the aid of a GALFORM (Cole et al.) mock 2PIGG catalogue. When comparing the group ellipticities in mock and real catalogues, we find an excellent agreement between the trends of shapes with number of group members. When carefully taking into account the effects of low-number statistics, we find that more massive groups are consistent with more elongated shapes. Finally, our studies find no significant correlations between the shapes of observed 2PIGG or SDSS-DR3GC groups with the properties of galaxy members such as colour- or spectral-type index.
dc.fuente.origenWOS
dc.identifier.doi10.1111/j.1365-2966.2005.09934.x
dc.identifier.eissn1365-2966
dc.identifier.issn0035-8711
dc.identifier.urihttps://doi.org/10.1111/j.1365-2966.2005.09934.x
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/96129
dc.identifier.wosidWOS:000235696500030
dc.issue.numero4
dc.language.isoen
dc.pagina.final1510
dc.pagina.inicio1503
dc.revistaMonthly notices of the royal astronomical society
dc.rightsacceso restringido
dc.subjectmethods : N-body simulations
dc.subjectgalaxies : kinematics and dynamics
dc.subjectcosmology : theory
dc.subjectlarge-scale structure of Universe
dc.titleShapes of clusters and groups of galaxies
dc.typeartículo
dc.volumen366
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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