On the Incorporation of Metallicity Data into Star Formation History Measurements from Resolved Stellar Populations

Abstract

The combination of spectroscopic stellar metallicities and resolved star color-magnitude diagrams (CMDs) has the potential to constrain the entire star formation and chemical enrichment history (SFH) of a galaxy better than fitting CMDs alone (as is most common in SFH studies using resolved stellar populations). In this paper, two approaches for incorporating external metallicity information into color-magnitude diagram fitting techniques are presented. Overall, the joint fitting of metallicity and CMD information can increase the precision on measured age-metallicity relationships and star formation rates by ~10% over CMD fitting alone. However, systematics in stellar isochrones and mismatches between spectroscopic and photometric metallicity determinations can reduce the accuracy of the recovered SFHs. I present a simple mitigation of these systematics that can reduce the amplitude of these systematics to the level obtained from CMD fitting alone, while ensuring the age-metallicity relationship is consistent with spectroscopic metallicities. As is the case in CMD-fitting analysis, improved stellar models and calibrations between spectroscopic and photometric metallicities are currently the primary impediment to gains in SFH precision from jointly fitting stellar metallicities and CMDs.

12 pages, 4 figures. Accepted for publication in the Astrophysical Journal

References in corpus (3)

• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• The ACS Nearby Galaxy Survey Treasury IX. Constraining asymptotic giant branch evolution with old metal-poor galaxies
• The episodic Star Formation History of the Carina Dwarf Spheroidal Galaxy

Cited by in corpus (6)

• The ISLAndS project II: The Lifetime Star Formation Histories of Six Andromeda dSphs
• METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble program. I. Overview and Initial Results
• A New Approach to Convective Core Overshooting: Probabilistic Constraints from Color-Magnitude Diagrams of LMC Clusters
• From K giants to G dwarfs: stellar lifetime effects on metallicity distributions derived from red giants
• Measuring Resolved Star Formation Histories from High-Precision Color-Magnitude Diagrams with StarFormationHistories.jl
• Stars Born in the Wind: M82's Outflow and Halo Star Formation