On the Estimation of Systematic Uncertainties of Star Formation Histories

TL;DR

This paper proposes a method to incorporate systematic uncertainties from stellar evolution models into star formation history measurements, addressing a major source of error often neglected in current analyses.

Contribution

It introduces a calibration-based process to estimate and include systematic uncertainties from isochrone models in SFH measurements.

Findings

Systematic errors can significantly affect SFH results.

The proposed method improves uncertainty estimates in shallow photometry.

Inclusion of model uncertainties enhances the reliability of SFH measurements.

Abstract

In most star formation history (SFH) measurements, the reported uncertainties are those due to effects whose sizes can be readily measured: Poisson noise, adopted distance and extinction, and binning choices in the solution itself. However, the largest source of error, systematics in the adopted isochrones, is usually ignored and very rarely explicitly incorporated into the uncertainties. I propose a process by which estimates of the uncertainties due to evolutionary models can be incorporated into the SFH uncertainties. This process relies on application of shifts in temperature and luminosity, the sizes of which must be calibrated for the data being analyzed. While there are inherent limitations, the ability to estimate the effect of systematic errors and include them in the overall uncertainty is significant. Effects of this are most notable in the case of shallow photometry, with which SFH measurements rely on evolved stars.