Inferring physical properties of galaxies from their emission line spectra

Abstract

We present a new approach based on Supervised Machine Learning (SML) algorithms to infer key physical properties of galaxies (density, metallicity, column density and ionization parameter) from their emission line spectra. We introduce a numerical code (called GAME, GAlaxy Machine learning for Emission lines) implementing this method and test it extensively. GAME delivers excellent predictive performances, especially for estimates of metallicity and column densities. We compare GAME with the most widely used diagnostics (e.g. R${}_{23}$, [NII]$\lambda$6584 / H$\alpha$ indicators) showing that it provides much better accuracy and wider applicability range. GAME is particularly suitable for use in combination with Integral Field Unit (IFU) spectroscopy, both for rest-frame optical/UV nebular lines and far-infrared/sub-mm lines arising from Photo-Dissociation Regions. Finally, GAME can also be applied to the analysis of synthetic galaxy maps built from numerical simulations.

14 pages, 11 figures, accepted for publication in MNRAS

References in corpus (9)

• The MAPPINGS III Library of Fast Radiative Shock Models
• The Effects of Stellar Rotation. II. A Comprehensive Set of Starburst99 Models
• IZI: Inferring the Gas Phase Metallicity (Z) and Ionization Parameter (q) of Ionized Nebulae using Bayesian Statistics
• Robust Machine Learning Applied to Astronomical Datasets I: Star-Galaxy Classification of the SDSS DR3 Using Decision Trees
• Fundamental Parameters of Main-Sequence Stars in an Instant with Machine Learning
• Far-infrared line spectra of Seyfert galaxies from the Herschel-PACS Spectrometer
• Data augmentation for machine learning redshifts applied to SDSS galaxies
• Star Formation Rate Determinations
• Robust Machine Learning Applied to Terascale Astronomical Datasets

Cited by in corpus (2)

• Surveying the reach and maturity of machine learning and artificial intelligence in astronomy
• The Herschel Dwarf Galaxy Survey: II. Physical conditions, origin of [CII] emission, and porosity of the multiphase low-metallicity ISM