MODELING THE METALLICITY DISTRIBUTION OF GLOBULAR CLUSTERS

By A. Muratov, O. Gnedin. 2010

236 citations recorded by the source corpus.

Observed metallicities of globular clusters reflect physical conditions in the interstellar medium of their high-redshift host galaxies. Globular cluster systems in most large galaxies display bimodal color and metallicity distributions, which are often interpreted as indicating two distinct modes of cluster formation. The metal-rich and metal-poor clusters have systematically different locations and kinematics in their host galaxies. However, the red and blue clusters have similar internal properties, such as their masses, sizes, and ages. It is therefore interesting to explore whether both metal-rich and metal-poor clusters could form by a common mechanism and still be consistent with the bimodal distribution. We present such a model, which prescribes the formation of globular clusters semi-analytically using galaxy assembly history from cosmological simulations coupled with observed scaling relations for the amount and metallicity of cold gas available for star formation. We assume that massive star clusters form only during mergers of massive gas-rich galaxies and tune the model parameters to reproduce the observed distribution in the Galaxy. A wide, but not the entire, range of model realizations produces metallicity distributions consistent with the data. We find that early mergers of smaller hosts create exclusively blue clusters, whereas subsequent mergers of more massive galaxies create both red and blue clusters. Thus, bimodality arises naturally as the result of a small number of late massive merger events. This conclusion is not significantly affected by the large uncertainties in our knowledge of the stellar mass and cold gas mass in high-redshift galaxies. The fraction of galactic stellar mass locked in globular clusters declines from over 10% at z > 3 to 0.1% at present.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/4a70ba138fe9ed57c246773881984f76e70c541f

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

THE BIMODAL METALLICITY DISTRIBUTION OF THE COOL CIRCUMGALACTIC MEDIUM AT z ≲ 1 (2013, methodology): “For the description of the GMM method, its advantages and limitations, we refer the reader to the appendix in Muratov & Gnedin (2010).”
CRITICAL ASSESSMENT OF AUTOMATED FLOW CYTOMETRY DATA ANALYSIS TECHNIQUES (2013, background): “D > 2 is required for a clean separation between the two modes (as reported in [32]); • The misclassification area A, defined as the overlapping area under the two normal distributions (as reported in [33]).”
On the fraction of star formation occurring in bound stellar clusters (2012, methodology): “Analytic models for the evolution of star cluster populations have recently been implemented in numerical simulations of galaxy formation and evolution (Prieto & Gnedin 2008; Muratov & Gnedin 2010; Kruijssen et al. 2011, 2012b).”
The SLUGGS Survey: kinematics for over 2500 globular clusters in 12 early-type galaxies (2012, background): “…side, there is a lack of consensus regarding the leading processes that drive the formation of GC systems (i.e. merging, collapse, accretion) and whether one (see Muratov & Gnedin 2010) or more of these processes (e.g. Lee et al. 2010) are needed to explain the observed colour bimodality.”
GLOBULAR CLUSTERS IN THE OUTER GALACTIC HALO: NEW HUBBLE SPACE TELESCOPE/ADVANCED CAMERA FOR SURVEYS IMAGING OF SIX GLOBULAR CLUSTERS AND THE GALACTIC GLOBULAR CLUSTER AGE–METALLICITY RELATION (2011, methodology): “…model for the Sagittarius dwarf spheroidal galaxy from Siegel et al. (2007); the lower-left panel shows the chemical evolution models of the Magellanic Clouds from Pagel & Tautvaǐsienė (1998); and the lower-right panel shows the mean trend from the GC formation model of Muratov & Gnedin (2010).”
The bifurcated age–metallicity relation of Milky Way globular clusters and its implications for the accretion history of the galaxy (2013, background): “Similarly the work of Muratov & Gnedin (2010) which incorporated many aspects in agreement with our analysis, is not problematic in its suggestion that large age spreads are likely in both the metal poor (MP) and metal rich (MR) GC populations (with that study also finding a similar ratio of…”
Globular clusters as the relics of regular star formation in ‘normal’ high-redshift galaxies (2015, background): “…1977; Chernoff & Weinberg 1990; Gnedin & Ostriker 1997; Vesperini 2001; Fall & Zhang 2001; McLaughlin & Fall 2008; Lamers, Baumgardt & Gieles 2010; Muratov & Gnedin 2010; Li & Gnedin 2014), thereby omitting the early phase of GC formation and evolution within the gas-rich discs of their host…”
Globular cluster systems in nearby dwarf galaxies – III. Formation efficiencies of old globular clusters (2010, unknown): “Semi-analytical models of cluster formation are able to reproduce the GC metallicity and age distributions assuming formation of GCs during galaxy merging (e.g. Muratov & Gnedin 2010).”
Chemical tagging with APOGEE: Discovery of a large population of N-rich stars in the inner Galaxy (2016, background): “Globular cluster formation motivated by mergers of gas-rich galaxies is another possible mechanism (Ashman & Zepf 1992; Muratov & Gnedin 2010), but one thought to make a minor contribution to the total stellar mass allocated in GC systems today (Kravtsov & Gnedin 2005).”
CO-EVOLUTION OF GALACTIC NUCLEI AND GLOBULAR CLUSTER SYSTEMS (2013, background): “Such conditions could be realized, for example, during major mergers of gas-rich galaxies, as suggested for the formation of globular clusters by Muratov & Gnedin (2010).”