A Comprehensive Catalog of Emission-line Nebulae, Star Clusters, and Supergiants in M31 from the LAMOST Spectroscopic Survey

TL;DR

This paper presents a comprehensive catalog of emission-line nebulae, star clusters, and supergiants in M31, derived from LAMOST spectroscopic data, utilizing machine learning and detailed spectral analysis to enhance understanding of the galaxy's structure and stellar populations.

Contribution

The first extensive catalog of M31's stellar and nebular objects from LAMOST data, classified with a random forest algorithm and validated through spectral and morphological examination.

Findings

Catalog includes 384 emission-line nebulae, 380 star clusters, 375 supergiants.

Radial velocities and emission line fluxes were measured for nebulae.

Identified 245 emission-line nebulae in M33.

Abstract

Spectroscopic observations of various tracers in nearby galaxies, such as Andromeda (M31), play a crucial role in identifying and classifying individual stellar populations and nebular objects, thereby enhancing our understanding of galactic composition, environment, and dynamics as well as stellar evolution. While the LAMOST (Large Sky Area Multi-Object Fibre Spectroscopic Telescope) survey of M31 has produced extensive datasets, a comprehensive catalog of emission-line nebulae, star clusters, and supergiants is yet to be completed. In this paper, we present a final catalog of 384 emission-line nebulae, 380 star clusters, and 375 supergiants and candidates in M31, as carefully selected and identified from the LAMOST spectroscopic database. These objects were classified using a random forest algorithm, followed by thorough visual examinations of their spectral characteristics as well as morphologies revealed by archive images. For emission-line nebulae, we measured radial velocities and relative fluxes of emission lines, enabling further classification of planetary nebulae and HII regions. Additionally, we identified 245 emission-line nebulae in M33. This work lays the data foundation for the study of M31, and offers valuable tracers to investigate M31's structure and evolution.