A tight relation between the age distributions of stellar clusters and the properties of the interstellar medium in the host galaxy

Abstract

The age distributions of stellar cluster populations have long been proposed to probe the recent formation history of the host galaxy. However, progress is hampered by the limited understanding of cluster disruption by evaporation and tidal shocks. We study the age distributions of clusters in smoothed particle hydrodynamics simulations of isolated disc galaxies, which include a self-consistent, physical model for the formation and dynamical evolution of the cluster population and account for the variation of cluster disruption in time and space. We show that the downward slope of the cluster age distribution due to disruption cannot be reproduced with a single functional form, because the disruption rate exhibits systematic trends with cluster age (the `cruel cradle effect'). This problem is resolved by using the median cluster age to trace cluster disruption. Across 120 independent galaxy snapshots and simulated cluster populations, we perform two-dimensional power law fits of the median cluster age to various macroscopic physical quantities and find that it scales as $t_{\mathrm{med}}\propto {\Sigma }^{-0.51\pm 0.03}{\sigma }_{1D}^{-0.85\pm 0.10}{M}_{\min }^{\gamma }$, for the gas surface density $\Sigma$, gas velocity dispersion ${\sigma }_{1D}$, and minimum cluster mass $M_{\min }$. This scaling accurately describes observed cluster populations and indicates disruption by impulsive tidal shocks from the interstellar medium. The term $M_{\min }^{\gamma }$ provides a model-independent way to measure the mass dependence of the cluster disruption time $\gamma$. Finally, the ensemble-average cluster lifetime depends on the gas density less strongly than the instantaneous disruption time of single clusters. These results reflect the variation of cluster disruption in time and space. We provide quantitative ways of accounting for these physics in cluster population studies.

15 pages, 6 figures, 3 tables; accepted by MNRAS (May 24, 2017)

References in corpus (20)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• The Resolved Properties of Extragalactic Giant Molecular Clouds
• The ACS Virgo Cluster Survey. XII. The Luminosity Function of Globular Clusters in Early Type Galaxies
• Star cluster disruption by giant molecular clouds
• Legacy ExtraGalactic UV Survey (LEGUS) with The Hubble Space Telescope. I. Survey Description
• The mass function of young star clusters in spiral galaxies
• The life cycle of star cluster in a tidal field
• Probing the role of the galactic environment in the formation of stellar clusters; using M83 as a test bench
• A Wide-field High Resolution HI Mosaic of Messier 31: I. Opaque Atomic Gas and Star Formation Rate Density
• A complete 12CO 2-1 map of M51 with HERA: I. Radial averages of CO, HI, and radio continuum
• Modeling the Formation of Globular Cluster Systems in the Virgo Cluster
• A Portrait of Cold Gas in Galaxies at 60pc Resolution and a Simple Method to Test Hypotheses That Link Small-Scale ISM Structure to Galaxy-Scale Processes
• ACS imaging of star clusters in M51. I. Identification and radius distribution
• Incorporating the molecular gas phase in galaxy-size numerical simulations: first applications in dwarf galaxies
• The photometric evolution of star clusters and the preferential loss of low-mass bodies - with an application to globular clusters
• The Effect of Orbital Eccentricity on the Dynamical Evolution of Star Clusters
• The Effects of Orbital Inclination on the Scale Size and Evolution of Tidally Filling Star Clusters
• The Young Cluster Population of M82 Region B
• The effect of secular galactic growth on the evolution of star clusters

Cited by in corpus (13)

• The E-MOSAICS project: tracing galaxy formation and assembly with the age-metallicity distribution of globular clusters
• Star clusters near and far; tracing star formation across cosmic time
• Formation histories of stars, clusters and globular clusters in the E-MOSAICS simulations
• Introducing EMP-Pathfinder: modelling the simultaneous formation and evolution of stellar clusters in their host galaxies
• Where did the globular clusters of the Milky Way form? Insights from the E-MOSAICS simulations
• Implementing Primordial Binaries in Simulations of Star Cluster Formation with a Hybrid MHD and Direct N-Body Method
• Improving Star Cluster Age Estimates in PHANGS-HST Galaxies and the Impact on Cluster Demographics in NGC 628
• Massive Star Cluster Formation and Destruction in Luminous Infrared Galaxies in GOALS II: An ACS/WFC3 Survey of Nearby LIRGs
• Star Cluster Formation and Evolution in M101: An Investigation with the Legacy Extragalactic UV Survey
• A systematic analysis of star cluster disruption by tidal shocks -- II. Predicting star cluster dissolution rates from a time-series analysis of their tidal histories
• The Initial Properties of Young Star Clusters in M83
• The formation and disruption of globular cluster populations in simulations of present-day $L^{\ast }$ galaxies with controlled assembly histories
• The dynamical evolution of the stellar clumps in the Sparkler galaxy