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The VMC survey – XXV. The 3D structure of the Small Magellanic Cloud from Classical Cepheids

Ripepi, Vincenzo; Cioni, Maria-Rosa L.; Ida Moretti, Maria; Marconi, Marcella; Bekki, Kenji; Clementini, Gisella; de Grijs, Richard; Emerson, Jim; Groenewegen, Martin A.T.; Ivanov, Valentin D.; Molinaro, Roberto; Muraveva, Tatiana; Oliveira, Joana M.; Piatti, Andrés E.; Subramanian, Smitha; Van Loon, Jacco Th.

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Authors

Vincenzo Ripepi

Maria-Rosa L. Cioni

Maria Ida Moretti

Marcella Marconi

Kenji Bekki

Gisella Clementini

Richard de Grijs

Jim Emerson

Martin A.T. Groenewegen

Valentin D. Ivanov

Roberto Molinaro

Tatiana Muraveva

Andrés E. Piatti

Smitha Subramanian



Abstract

The VISTA near-infrared YJKs survey of the Magellanic System (VMC) is collecting deep Ks-band time-series photometry of pulsating stars hosted by the two Magellanic Clouds and their connecting bridge. Here, we present Y, J, Ks light curves for a sample of 717 Small Magellanic Cloud (SMC) Classical Cepheids (CCs). These data, complemented with our previous results and V magnitude from literature, allowed us to construct a variety of period–luminosity and period–Wesenheit relationships, valid for Fundamental, First and Second Overtone pulsators. These relations provide accurate individual distances to CCs in the SMC over an area of more than 40 deg2. Adopting literature relations, we estimated ages and metallicities for the majority of the investigated pulsators, finding that (i) the age distribution is bimodal, with two peaks at 120 ± 10 and 220 ± 10 Myr; (i) the more metal-rich CCs appear to be located closer to the centre of the galaxy. Our results show that the three-dimensional distribution of the CCs in the SMC is not planar but heavily elongated for more than 25–30 kpc approximately in the east/north-east towards south-west direction. The young and old CCs in the SMC show a different geometric distribution. Our data support the current theoretical scenario predicting a close encounter or a direct collision between the Clouds some 200 Myr ago and confirm the presence of a Counter-Bridge predicted by some models. The high-precision three-dimensional distribution of young stars presented in this paper provides a new test bed for future models exploring the formation and evolution of the Magellanic System.

Journal Article Type Article
Acceptance Date Aug 10, 2017
Online Publication Date Aug 18, 2017
Publication Date 2017-11
Publicly Available Date Mar 29, 2024
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 472
Issue 1
Pages 808 -827
DOI https://doi.org/10.1093/mnras/stx2096
Keywords stars, oscillations, variables, Cepheids,,variables, RR Lyrae, Magellanic Clouds, galaxies, structure
Publisher URL http://dx.doi.org/10.1093/mnras/stx2096

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