Stellar populations of galaxies in the LAMOST spectral survey

TL;DR

This study derives stellar population properties like age and metallicity for approximately 43,000 low-redshift galaxies from the LAMOST survey, using a spectral fitting method that avoids flux calibration biases, and demonstrates its application through galaxy pair analysis.

Contribution

Introduces a new spectral fitting algorithm to accurately determine stellar ages and metallicities for LAMOST galaxies lacking SDSS spectra, with a publicly available catalog.

Findings

Successfully recovers galaxy stellar ages and metallicities down to S/N ≥ 5.

Provides a comprehensive catalog of stellar population properties for 43,000 galaxies.

Demonstrates the use of the catalog by analyzing the Holmberg effect in galaxy pairs.

Abstract

We firstly derive the stellar population properties: age and metallicity for $\sim$ 43,000 low redshift galaxies in the seventh data release (DR7) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey, which have no spectroscopic observations in the Sloan Digital Sky Survey(SDSS). We employ a fitting procedure based on the small-scale features of galaxy spectra so as to avoid possible biases from the uncertain flux calibration of the LAMOST spectroscopy. We show that our algorithm can successfully recover the average age and metallicity of the stellar populations of galaxies down to signal-to-noise$\geq$5 through testing on both mock galaxies and real galaxies comprising LAMOST and their SDSS counterparts. We provide a catalogue of the age and metallicity for $\sim$ 43,000 LAMOST galaxies online. As a demonstration of the scientific application of this catalogue, we present the Holmberg effect on both age and metallicity of a sample of galaxies in galaxy pairs.