The colour-magnitude relation of Globular Clusters in Centaurus and Hydra - Constraints on star cluster self-enrichment with a link to massive Milky Way GCs
J. Fensch, S. Mieske, J. Mueller-Seidlitz, M. Hilker
备注：
15 pages, 13 figures. Language edited version of paper accepted for publication in Astronomy & Astrophysics. Colour-composite in Figure 1 reduced in resolution
We investigate the colour-magnitude relation of metal-poor globular clusters, the 'blue tilt', in the Hydra and Centaurus galaxy clusters and constrain the primordial conditions for star cluster self-enrichment. We analyse U,I photometry for about 2500 globular clusters in the central regions of Hydra and Centaurus, based on FORS1@VLT data. We convert the measured colour-magnitude relations into mass-metallicity space and obtain a scaling of Z \propto M^{0.27 \pm 0.05} for Centaurus GCs and Z \propto M^{0.40 \pm 0.06} for Hydra GCs, consistent with results in other environments. We find that the GC mass-metallicity relation already sets in at present-day masses of a few 10^5 solar masses and is well established in the luminosity range of massive MW clusters like omega Centauri. We compare the mass-metallicity relation with predictions from the star cluster self-enrichment model by Bailin & Harris (2009). For this we include effects of dynamical and stellar evolution and a physically well motivated primordial mass-radius scaling. The self-enrichment model reproduces the observed relations well for average primordial half-light radii r_h ~ 1-1.5 pc, star formation efficiencies f_* ~ 0.3-0.4, and pre-enrichment levels of [Fe/H] ~ -1.7 dex. Within the self-enrichment scenario, the observed blue tilt implies a correlation between GC mass and width of the stellar metallicity distribution. We find that this implied correlation matches the trend of width with GC mass measured in Galactic GCs, including extreme cases like omega Cen and M54. We conclude that 1. A primordial star cluster mass-radius relation provides a significant improvement to the self-enrichment model fits. 2. Broadenend metallicity distributions as found in some massive MW globular clusters may have arisen naturally from self-enrichment processes, without the need of a dwarf galaxy progenitor.
A model for the ongoing subcluster interaction in Centaurus
European Southern Observatory（欧洲南方天文台）；Universitätssternwarte der Ludwig-Maximilians Universität（路德维希-马克西米利安大学大学天文台）；INAF – Astronomical Observatory of Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；Max-Planck-Institut für Extraterrestrische Physik（马克斯·普朗克地外物理学研究所）；Departamento de Astronomía, Universidad de Concepción（康塞普西翁大学天文学系）；INAF – Astronomical Observatory of Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）；Gran Sasso Science Institute（格兰萨索科学研究所）
Nonlinear Color-Metallicity Relations of Globular Clusters. XI. Nonlinearity Effect Revealed by NGC 5128 (Centaurus A) and NGC 4594 (Sombrero) Galaxies
Intracluster globular clusters as tracers of the mass assembly of the Hydra I galaxy cluster
European Southern Observatory（欧洲南方天文台）；Universitätssternwarte der Ludwig-Maximilians Universität（路德维希-马克西米利安大学大学天文台）；INAF – Astronomical Observatory of Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；Max-Planck-Institut für Extraterrestrische Physik（马克斯·普朗克地外物理学研究所）；INAF – Astronomical Observatory of Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）；Gran Sasso Science Institute（格兰萨索科学研究所）
Looking into the faintEst WIth MUSE (LEWIS): Exploring the nature of ultra-diffuse galaxies in the Hydra-I cluster IV. A study of the Globular Cluster population in four UDGs
INAF Osservatorio Astr. d’Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）；European Southern Observatory（欧洲南方天文台）；Gran Sasso Science Institute（格兰萨索科学研究所）；INAF – Astronomical Observatory of Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；Centre for Astrophysics and Supercomputing, Swinburne University（斯威本大学天体物理学与超级计算中心）；Finnish Centre for Astronomy with ESO, (FINCA), University of Turku（图尔库大学芬兰ESO天文学中心）；Tuorla Observatory, Department of Physics and Astronomy, University of Turku（图尔库大学物理与天文学系图奥拉天文台）；Turku Collegium for Science, Medicine and Technology（图尔库科学技术学院）
Distance measurements from the internal dynamics of globular clusters: Application to the Sombrero galaxy (M104)
University of Vienna（维也纳大学）；Instituto de Astrofísica de Canarias（加那利天体物理学研究所）；Universidad de La Laguna（拉古纳大学）；Swinburne University（斯威本科技大学）；Durham University（杜伦大学）；Indiana University（印第安纳大学）；Universidade Federal do Rio Grande do Sul (UFRGS)（南里奥格兰德联邦大学）；European Southern Observatory（欧洲南方天文台）；Ecole Polytechnique Fédérale de Lausanne (EPFL)（洛桑联邦理工学院）；University of Cambridge（剑桥大学）
Horizontal branch structure, age, and chemical composition for very metal-poor extragalactic globular clusters
Special Astrophysical Observatory, Russian Academy of Sciences（俄罗斯科学院特别天体物理观测台）；South African Astronomical Observatory（南非天文台）；Southern African Large Telescope Foundation（南半球大型望远镜基金会）；Sternberg Astronomical Institute, Lomonosov Moscow State University（莫斯科国立大学列别捷夫天体物理研究所）；Department of Physics, Southern Federal University（南联邦大学物理系）
Looking into the faintEst WIth MUSE (LEWIS): on the nature of ultra-diffuse galaxies in the Hydra-I cluster.I. Project description and preliminary results
Looking into the faintEst WIth MUSE (LEWIS): Exploring the nature of ultra-diffuse galaxies in the Hydra-I cluster. VI. A star-forming UDG in Hydra I: a rare UDG or a transition phase?
University of Naples “Federico II”（那不勒斯费德里科二世大学）；Armagh Observatory and Planetarium（阿马赫天文台和天文馆）；Gran Sasso Science Institute（格兰萨索科学研究所）；Finnish Centre for Astronomy with ESO, (FINCA), University of Turku（图尔库大学芬兰ESO天文中心）；Tuorla Observatory, Department of Physics and Astronomy, University of Turku（图尔库大学物理与天文学系图奥拉天文台）；Turku Collegium for Science（图尔库科学学院）
Looking into the faintEst WIth MUSE (LEWIS): Exploring the nature of ultra-diffuse galaxies in the Hydra I cluster III. Untangling UDG 32 from the stripped filaments of NGC 3314A with multi-wavelength data
