The influence of halo assembly on galaxies and galaxy groups

In this paper, we study the variations of group galaxy properties according to the assembly history in Sloan Digital Sky Survey Data Release 6 (SDSS-DR6) selected groups. Using mock SDSS group catalogues, we find two suitable indicators of group formation time: (i) the isolation of the group, define...

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Detalles Bibliográficos
Publicado: 2009
Materias:
Galaxies: clusters: general
Galaxies: general
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00358711_v394_n4_p2229_Zapata
http://hdl.handle.net/20.500.12110/paper_00358711_v394_n4_p2229_Zapata
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_00358711_v394_n4_p2229_Zapata
record_format dspace
spelling paper:paper_00358711_v394_n4_p2229_Zapata2023-06-08T15:01:26Z The influence of halo assembly on galaxies and galaxy groups Galaxies: clusters: general Galaxies: general In this paper, we study the variations of group galaxy properties according to the assembly history in Sloan Digital Sky Survey Data Release 6 (SDSS-DR6) selected groups. Using mock SDSS group catalogues, we find two suitable indicators of group formation time: (i) the isolation of the group, defined as the distance to the nearest neighbour in terms of its virial radius and (ii) the concentration, measured as the group inner density calculated using the fifth nearest bright galaxy to the group centre. Groups within narrow ranges of mass in the mock catalogue show increasing group age with isolation and concentration. However, in the observational data the stellar age, as indicated by the spectral type, only shows a correlation with concentration. We study groups of similar mass and different assembly history, finding important differences in their galaxy population. Particularly, in high-mass SDSS groups, the number of members, mass-to-light ratios, red galaxy fractions and the magnitude difference between the brightest and second-brightest group galaxies, show different trends as a function of isolation and concentration, even when it is expected that the latter two quantities correlate with group age. Conversely, low-mass SDSS groups appear to be less sensitive to their assembly history. The correlations detected in the SDSS are not consistent with the trends measured in the mock catalogues. However, discrepancies can be explained in terms of the disagreement found in the age-isolation trends, suggesting that the model might be overestimating the effects of environment. We discuss how the modelling of the cold gas in satellite galaxies could be responsible for this problem. These results can be used to improve our understanding of the evolution of galaxies in high-density environments. © 2009 The Authors. Journal compilation © 2009 RAS. 2009 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00358711_v394_n4_p2229_Zapata http://hdl.handle.net/20.500.12110/paper_00358711_v394_n4_p2229_Zapata
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Galaxies: clusters: general
Galaxies: general
spellingShingle Galaxies: clusters: general
Galaxies: general
The influence of halo assembly on galaxies and galaxy groups
topic_facet Galaxies: clusters: general
Galaxies: general
description In this paper, we study the variations of group galaxy properties according to the assembly history in Sloan Digital Sky Survey Data Release 6 (SDSS-DR6) selected groups. Using mock SDSS group catalogues, we find two suitable indicators of group formation time: (i) the isolation of the group, defined as the distance to the nearest neighbour in terms of its virial radius and (ii) the concentration, measured as the group inner density calculated using the fifth nearest bright galaxy to the group centre. Groups within narrow ranges of mass in the mock catalogue show increasing group age with isolation and concentration. However, in the observational data the stellar age, as indicated by the spectral type, only shows a correlation with concentration. We study groups of similar mass and different assembly history, finding important differences in their galaxy population. Particularly, in high-mass SDSS groups, the number of members, mass-to-light ratios, red galaxy fractions and the magnitude difference between the brightest and second-brightest group galaxies, show different trends as a function of isolation and concentration, even when it is expected that the latter two quantities correlate with group age. Conversely, low-mass SDSS groups appear to be less sensitive to their assembly history. The correlations detected in the SDSS are not consistent with the trends measured in the mock catalogues. However, discrepancies can be explained in terms of the disagreement found in the age-isolation trends, suggesting that the model might be overestimating the effects of environment. We discuss how the modelling of the cold gas in satellite galaxies could be responsible for this problem. These results can be used to improve our understanding of the evolution of galaxies in high-density environments. © 2009 The Authors. Journal compilation © 2009 RAS.
title The influence of halo assembly on galaxies and galaxy groups
title_short The influence of halo assembly on galaxies and galaxy groups
title_full The influence of halo assembly on galaxies and galaxy groups
title_fullStr The influence of halo assembly on galaxies and galaxy groups
title_full_unstemmed The influence of halo assembly on galaxies and galaxy groups
title_sort influence of halo assembly on galaxies and galaxy groups
publishDate 2009
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00358711_v394_n4_p2229_Zapata
http://hdl.handle.net/20.500.12110/paper_00358711_v394_n4_p2229_Zapata
_version_ 1768545964978601984

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