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

2017/07/31 by Vincenzo Ripepi, V. Ripepi, Maria-Rosa L. Cioni +23 · 3 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Cepheid variable #Galaxy #Large Magellanic Cloud #Metallicity #Photometry (optics) #Physics #Small Magellanic Cloud #Stars #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR

paper · pdf · doi:10.1093/mnras/stx2096

21 Pages. Accepted for publication in MNRAS. Minor changes with respect to previous version

arxiv created 2017/08/10 · openalex publication_date 2017/08/17 · arxiv updated 2017/09/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

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.

Citations

• Beasts of the Southern Wild: Discovery of nine Ultra Faint satellites in the vicinity of the Magellanic Clouds
• Magellanic Cloud Structure from Near-Infrared Surveys. I. The Viewing Angles of the Large Magellanic Cloud
• Limits on the Macho content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds
• The geometry and distance of the Magellanic Clouds from Cepheid variables
• Are the Magellanic Clouds on Their First Passage about the Milky Way?
• Formation of the Small Magellanic Cloud: An Ancient Major Merger as a Solution to the Kinematical Differences between Old Stars and H i Gas
• Kinematics of massive stars in the Small Magellanic Cloud
• METAL ABUNDANCES, RADIAL VELOCITIES, AND OTHER PHYSICAL CHARACTERISTICS FOR THE RR LYRAE STARS IN THEKEPLERFIELD
• Eclipsing binary stars in the Large Magellanic Cloud: results from the EROS-2, OGLE and VMC surveys★

Cited by

• Revisiting a detached stellar structure in the outer northeastern region of the Small Magellanic Cloud
• Gaia EDR3 Proper Motions of Milky Way Dwarfs. I. 3D Motions and Orbits
• Metallicities and ages for 35 star clusters and their surrounding fields in the Small Magellanic Cloud