The Star Formation History of Nearby Galaxies: A Machine Learning Approach

TL;DR

This paper introduces SFHNet, a deep learning approach using CNNs to efficiently and accurately derive star formation histories from color-magnitude diagrams of nearby galaxies, improving traditional methods with machine learning.

Contribution

The study develops and validates a CNN-based network, SFHNet, that enhances the efficiency and flexibility of the synthetic CMD method for star formation history estimation.

Findings

SFHNet accurately reproduces known SFHs from synthetic and HST data.

The method provides detailed insights into stellar density, initial mass, and SFR distributions.

Deep learning improves the speed and adaptability of SFH measurements.

Abstract

Reproducing color-magnitude diagrams (CMDs) of star-resolved galaxies is one of the most precise methods for measuring the star formation history (SFH) of nearby galaxies back to the earliest time. The upcoming big data era poses challenges to the traditional numerical technique in its capacity to deal with vast amounts of data, which motivates us to explore the feasibility of employing machine learning networks in this field. In this study, we refine the synthetic CMD method with a state-of-the-art theoretical stellar evolution model to simulate the properties of stellar populations, incorporate the convolutional neural network (CNN) in the fitting process to enhance the efficiency, and innovate the initial stellar mass estimation to improve the flexibility. The fine-tuned deep learning network, named \texttt{SFHNet}, has been tested with synthetic data and further validated with photometric data collected from the Hubble Space Telescope (\textit{HST}). The derived SFHs are largely in accordance with those reported in the literature. Furthermore, the network provides detailed insights into the distribution of stellar density, initial stellar mass, and star formation rate (SFR) over the age-metallicity map. The application of the deep learning network not only measures the SFH accurately but also enhances the synthetic CMD method's efficiency and flexibility, thereby facilitating a more comprehensive and in-depth understanding of nearby galaxies.