Anomalous Cepheids in the Large Magellanic Cloud: Insight into their origin and connection with the star formation history

Abstract

Context. The properties of variable stars can give independent constraints on the star formation history of the host galaxy, by determining the age and metallicity of the parent population. Aims. We investigate the pulsation properties of 84 Anomalous Cepheids (ACs) detected by the OGLE-III survey in the Large Magellanic Cloud (LMC), in order to understand the formation mechanism and the characteristics of the parent population they came from. Methods. We used an updated theoretical pulsation scenario to derive the mass and the pulsation mode of each AC in the sample. We also used a Kolmogorov-Smirnov test to analyze the spatial distribution of the ACs, in comparison with that of other groups of variable stars, and connect their properties with the star formation history of the LMC. Results. We find that the mean mass of ACs is 1.2 \pm 0.2Mo. We show that ACs do not follow the same spatial distribution of classical Cepheids. This and the difference in their period-luminosity relations further support the hypothesis that ACs are not the extension to low luminosity of classical Cepheids. The spatial distribution of ACs is also different from that of bona-fide tracers of the old population, such as RR Lyrae stars and population II Cepheids. We therefore suggest that the majority of ACs in the LMC are made of intermediate-age (1-6Gyr), metal-poor single stars. Finally, we investigate the relation between the frequency of ACs and the luminosity of the host galaxy, disclosing that purely old systems follow a very tight relation and that galaxies with strong intermediate-age and young star formation tend to have an excess of ACs, in agreement with their hosting ACs formed via both single and binary star channels.

10 pages, 7 figures, accepted for publication on A&A

References in corpus (14)

• New Optical Reddening Maps of the Large and Small Magellanic Clouds
• The Chemical Enrichment History of the Large Magellanic Cloud
• The Variable Stars of the Draco Dwarf Spheroidal Galaxy - Revisited
• Variable Stars in the Newly Discovered Milky Way Dwarf Spheroidal Satellite Canes Venatici I
• Evidence for an Overluminosity of the Variable Star RR Lyr, and a Revised Distance to the LMC
• Outside-in disk evolution in the LMC
• Metallicities, Age--Metallicity relationships, and Kinematics of Red Giant Branch Stars in the Outer Disk of the Large Magellanic Cloud
• The ACS LCID project VII: the blue stragglers population in the isolated dSph galaxies Cetus and Tucana
• Synthetic properties of bright metal-poor variables. II. BL Her stars
• The Araucaria Project. Accurate determination of the dynamical mass of the classical Cepheid in the eclipsing system OGLE-LMC-CEP-1812
• Synthetic properties of bright metal-poor variables. I. "Anomalous" Cepheids
• The ancient stellar population of M32: RR Lyr Variable stars confirmed
• MAD about the Large Magellanic Cloud: preparing for the era of Extremely Large Telescopes
• Variable Stars in Large Magellanic Cloud Globular Clusters I: NGC 1466

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