On the precision of full-spectrum fitting of simple stellar populations. II. The dependence on star cluster mass in the wavelength range 0.3-5.0 $\mu$m

Abstract

In this second paper of a series on the accuracy and precision of the determination of age and metallicity of simple stellar populations (SSPs) by means of the full spectrum fitting technique, we study the influence of star cluster mass through stochastic fluctuations of the number of stars near the top of the stellar mass function, which dominate the flux in certain wavelength regimes depending on the age. We consider SSP models based on the Padova isochrones, spanning the age range 7.0 $\le$ log (age/yr) $\le$ 10.1. Simulated spectra of star clusters in the mass range $10^4\le M/M_{\odot }<10^6$ are compared with SSP model spectra to determine best-fit ages and metallicities using a full-spectrum fitting routine in four wavelength regimes: the blue optical (0.35-0.70 $\mu$m), the red optical (0.6-1.0 $\mu$m), the near-IR (1.0-2.5 $\mu$m), and the mid-IR (2.5-5.0 $\mu$m). We compare the power of each wavelength regime in terms of both the overall precision of age and metallicity determination, and of its dependence on cluster mass. We also study the relevance of spectral resolution in this context by utilizing two different spectral libraries (BaSeL and BT-Settl). We highlight the power of the mid-IR regime in terms of identifying young massive clusters in dusty star forming regions in external galaxies. The spectra of the simulated star clusters and SSPs are made available online to enable follow-up studies by the community.

27 pages (incl. 8-page Appendix), 31 figures, published by MNRAS. Note: as of Jan 8, 2021, the bulk of the concluding Summary section is missing in the published version at MNRAS. They have been notified. This arXiv version is complete. Model spectra are being made available through CDS at http://cdsarc.u-strasbg.fr/viz-bin/qcat?VI/157

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Cited by in corpus (4)

• Detailed Chemical Abundances of Star Clusters in the Large Magellanic Cloud
• On the Precision of Full-spectrum Fitting of Stellar Populations. III. Identifying Age Spreads
• On the Precision of Full-Spectrum Fitting of Simple Stellar Populations. IV. A Systematic Comparison with Results from Colour-Magnitude Diagrams
• Clusters, Clumps, Dust, & Gas (CCDG) in NGC1614: Bench-marking Cluster Demographics in Extreme Systems