The SAGE-Spec Spitzer Legacy program: The life-cycle of dust and gas in the Large Magellanic Cloud. Point source classification I

TL;DR

This study classifies 197 infrared point sources in the Large Magellanic Cloud using a decision-tree approach based on spectral features, luminosity, and variability, revealing diverse stellar populations and validating photometric methods.

Contribution

Introduces a decision-tree classification method for infrared sources that integrates spectral, photometric, and variability data, applicable to large spectroscopic surveys.

Findings

Classified 197 sources into various stellar and extragalactic categories.

Identified 90 AGB stars and 29 young stellar objects among the sources.

Validated the effectiveness of photometric classification methods.

Abstract

We present the classification of 197 point sources observed with the Infrared Spectrograph in the SAGE-Spec Legacy program on the Spitzer Space Telescope. We introduce a decision-tree method of object classification based on infrared spectral features, continuum and spectral energy distribution shape, bolometric luminosity, cluster membership, and variability information, which is used to classify the SAGE-Spec sample of point sources. The decision tree has a broad application to mid-infrared spectroscopic surveys, where supporting photometry and variability information are available. We use these classifications to make deductions about the stellar populations of the Large Magellanic Cloud and the success of photometric classification methods. We find 90 asymptotic giant branch (AGB) stars, 29 young stellar objects, 23 post-AGB objects, 19 red supergiants, eight stellar photospheres, seven background galaxies, seven planetary nebulae, two HII regions and 12 other objects, seven of which remain unclassified.