The ACS Fornax Cluster Survey. X. Color gradients of globular cluster systems in early-type galaxies

Par Conseil national de recherches du Canada

DOI	Trouver le DOI : https://doi.org/10.1088/0004-637X/728/2/116
Auteur	Rechercher : Liu, Chengze; Rechercher : Peng, Eric W.; Rechercher : Jordan, Andrés; Rechercher : Ferrarese, Laura¹; Rechercher : Blakeslee, John P.¹; Rechercher : Côté, Patrick¹; Rechercher : Mei, Simona
Affiliation	Conseil national de recherches du Canada. Institut Herzberg d'astrophysique du CNRC
Format	Texte, Article
Sujet	galaxies: clusters: individual (Virgo, Fornax); galaxies: elliptical and lenticular, cD; galaxies: star clusters: general; galaxies: stellar content; globular clusters: general
Résumé	We use the largest homogeneous sample of globular clusters (GCs), drawn from the ACS Virgo Cluster Survey (ACSVCS) and ACS Fornax Cluster Survey (ACSFCS), to investigate the color gradients of GC systems in 76 early-type galaxies. We find that most GC systems possess an obvious negative gradient in (g-z) color with radius (bluer outward), which is consistent with previous work. For GC systems displaying color bimodality, both metal-rich and metal-poor GC subpopulations present shallower but significant color gradients on average, and the mean color gradients of these two subpopulations are of roughly equal strength. The field of view of ACS mainly restricts us to measuring the inner gradients of the studied GC systems. These gradients, however, can introduce an aperture bias when measuring the mean colors of GC subpopulations from relatively narrow central pointings. Inferred corrections to previous work imply a reduced significance for the relation between the mean color of metal-poor GCs and their host galaxy luminosity. The GC color gradients also show a dependence with host galaxy mass where the gradients are weakest at the ends of the mass spectrum-in massive galaxies and dwarf galaxies-and strongest in galaxies of intermediate mass, around a stellar mass of M(*) approximate to 10(10) M(circle dot). We also measure color gradients for field stars in the host galaxies. We find that GC color gradients are systematically steeper than field star color gradients, but the shape of the gradient-mass relation is the same for both. If gradients are caused by rapid dissipational collapse and weakened by merging, these color gradients support a picture where the inner GC systems of most intermediate-mass and massive galaxies formed early and rapidly with the most massive galaxies having experienced greater merging. The lack of strong gradients in the GC systems of dwarfs, which probably have not experienced many recent major mergers, suggests that low-mass halos were inefficient at retaining and mixing metals during the epoch of GC formation.
Date de publication	2011-01-28
Maison d’édition	American Astronomical Society IOP Publishing
Dans	The Astrophysical Journal 728, nº 2 : 1–10.
Langue	anglais
Publications évaluées par des pairs	Oui
Numéro NPARC	19739551
Exporter la notice	Exporter en format RIS
Signaler une correction	Signaler une correction (s'ouvre dans un nouvel onglet)
Identificateur de l’enregistrement	7780d820-42f0-4288-a49c-7b6fe25b47e6
Enregistrement créé	2012-03-29
Enregistrement modifié	2020-04-21

Date de modification :: 2024-07-01