Infrared variable stars in the compact elliptical galaxy M32

Abstract

Variable stars in the compact elliptical galaxy M32 are identified, using three epochs of photometry from the Spitzer Space Telescope at 3.6 and 4.5 $\mu$m, separated by 32 to 381 days. We present a high-fidelity catalogue of sources detected in multiple epochs at both 3.6 and 4.5 $\mu$m, which we analysed for stellar variability using a joint probability error-weighted flux difference. Of these, 83 stars are identified as candidate large-amplitude, long-period variables, with 28 considered high-confidence variables. The majority of the variable stars are classified as asymptotic giant branch star candidates using colour-magnitude diagrams. We find no evidence supporting a younger, infrared-bright stellar population in our M32 field.

11 pages, 8 figures. Accepted for publication in MNRAS

References in corpus (36)

• Evolution of asymptotic giant branch stars I. Updated synthetic TP-AGB models and their basic calibration
• Stellar Models and Yields of Asymptotic Giant Branch Stars
• Super and massive AGB stars - IV. Final fates - Initial to final mass relation
• Constraining the thermally-pulsing asymptotic giant branch phase with resolved stellar populations in the Small Magellanic Cloud
• Spitzer SAGE survey of the Large Magellanic Cloud II: Evolved Stars and Infrared Color Magnitude Diagrams
• Fundamental parameters and infrared excesses of Tycho-Gaia stars
• The WISE Extended Source Catalogue (WXSC) I: The 100 Largest Galaxies
• Comparative performance of selected variability detection techniques in photometric time series
• AGB Stars in the Fornax Dwarf Spheroidal Galaxy
• An Infrared Census of DUST in Nearby Galaxies with Spitzer (DUSTiNGS), II. Discovery of Metal-poor Dusty AGB Stars
• An Infrared Census of DUST in Nearby Galaxies with Spitzer (DUSTiNGS), I. Overview
• A new interpretation of the period-luminosity sequences of long-period variables
• Spitzer Infrared Spectrographic point source classification in the Small Magellanic Cloud
• Exploring wind-driving dust species in cool luminous giants III. Wind models for M-type AGB stars: dynamic and photometric properties
• The M33 Variable Star Population Revealed by Spitzer
• Mid-Infrared Variability from the Spitzer Deep, Wide-Field Survey
• The trigger of the AGB superwind: the importance of carbon
• Variable Evolved Stars and YSOs Discovered in the Large Magellanic Cloud using the SAGE Survey
• The evolution of DARWIN: current status of wind models for AGB stars
• An extensive grid of DARWIN models for M-type AGB stars I. Mass-loss rates and other properties of dust-driven winds
• The Magellanic Squall: Gas Replenishment from the Small to Large Magellanic Cloud
• Long period variable stars in NGC 147 and NGC 185. I. Their star formation histories
• An Infrared Census Of Dust In Nearby Galaxies With Spitzer (DUSTiNGS): V. The Period-luminosity Relation For Dusty Metal-Poor AGB Stars
• The onset of the AGB wind tied to a transition between sequences in the period-luminosity diagram
• The UK Infrared Telescope M33 monitoring project. IV. Variable red giant stars across the galactic disc
• On the formation mechanisms of compact elliptical galaxies
• A Dramatic Decrease in Carbon Star Formation in M31
• SPIRITS Catalog of Infrared Variables: Identification of Extremely Luminous Long Period Variables
• The Isaac Newton Telescope monitoring survey of Local Group dwarf galaxies. I. Survey overview and first results for Andromeda I
• A Remarkable Oxygen-rich Asymptotic Giant Branch Variable in the Sagittarius Dwarf Irregular Galaxy
• The Isaac Newton Telescope monitoring survey of Local Group dwarf galaxies -- IV. The star formation history of Andromeda VII derived from long period variable stars
• Two channels for the formation of compact dwarf galaxies in clusters of galaxies
• A Spitzer Space Telescope survey of extreme Asymptotic Giant Branch stars in M32
• Seeing Red in M32: Constraints on the Stellar Content from Near- and Mid-Infrared Observations and Applications for Studies of More Distant Galaxies
• Examining the Infrared Variable Star Population Discovered in the Small Magellanic Cloud Using the SAGE-SMC Survey
• Spitzer/IRAC Characterization of Galactic AGB Stars