SMASHing the low surface brightness SMC

Pol Massana, Noelia E.D. Noël, David L. Nidever, Denis Erkal, Thomas J.L. de Boer, Yumi Choi, Steven R. Majewski, Knut Olsen, Antonela Monachesi, Carme Gallart, Roeland P. van der Marel, Tomás Ruiz-Lara, Dennis Zaritsky, Nicolas F. Martin, Ricardo R. Muñoz, Maria Rosa L. Cioni, Cameron P.M. Bell, Eric F. Bell, Guy S. Stringfellow, Vasily BelokurovMatteo Monelli, Alistair R. Walker, David Martínez-Delgado, A. Katherina Vivas, Blair C. Conn

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The periphery of the Small Magellanic Cloud (SMC) can unlock important information regarding galaxy formation and evolution in interacting systems. Here, we present a detailed study of the extended stellar structure of the SMC using deep colour-magnitude diagrams, obtained as part of the Survey of the MAgellanic Stellar History (SMASH). Special care was taken in the decontamination of our data from Milky Way (MW) foreground stars, including from foreground globular clusters NGC 362 and 47 Tuc. We derived the SMC surface brightness using a 'conservative' approach from which we calculated the general parameters of the SMC, finding a staggered surface brightness profile. We also traced the fainter outskirts by constructing a stellar density profile. This approach, based on stellar counts of the oldest main-sequence turn-off stars, uncovered a tidally disrupted stellar feature that reaches as far out as 12 deg from the SMC centre. We also serendipitously found a faint feature of unknown origin located at ∼14 deg from the centre of the SMC and that we tentatively associated with a more distant structure. We compared our results to in-house simulations of a 1 × 109 M☉ SMC, finding that its elliptical shape can be explained by its tidal disruption under the combined presence of the MW and the Large Magellanic Cloud. Finally, we found that the older stellar populations show a smooth profile while the younger component presents a jump in the density followed by a flat profile, confirming the heavily disturbed nature of the SMC.

Original languageEnglish (US)
Pages (from-to)1034-1049
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Volume498
Issue number1
DOIs
StatePublished - Oct 1 2020

Keywords

  • Colour-magnitude diagrams
  • Galaxies: dwarf
  • Galaxies: interactions
  • Galaxies: structure
  • Hertzsprung-Russell
  • Techniques: photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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