Dark influences: Imprints of dark satellites on dwarf galaxies

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Context. In the context of the current Λ cold dark matter cosmological model small dark matter halos are abundant and satellites of dwarf galaxies are expected to be predominantly dark. Since low mass galaxies have smaller baryon fractions, interactions with these satellites may leave particularly dramatic imprints. Aims. We uncover the influence of the most massive of these dark satellites on disky dwarf galaxies and the possible dynamical and morphological transformations that result from these interactions. Methods. We use a suite of carefully set up, controlled simulations of isolated dwarf galaxies. The primary dwarf galaxies have solely a stellar disk in the dark matter halo and the secondaries are completely devoid of baryons. We vary the disk mass, halo concentration, initial disk thickness, and inclination of the satellite orbit. Results. The disky dwarf galaxies are heated and disrupted by the minor merger event, more extremely for higher satellite-to-disk-mass ratios, and the morphology and kinematics are significantly altered. Moreover, for less concentrated halos the minor merger can completely destroy the disk leaving a low-luminosity spheroidal-like galaxy instead. Conclusions. We conclude that dwarf galaxies are very susceptible to being disturbed by dark galaxies and that even a minor merger event can significantly disrupt and alter the structure and kinematics of a dwarf galaxy. This process may be seen as a new channel for the formation of dwarf spheroidal galaxies.

Original languageEnglish (US)
Article numberA59
JournalAstronomy and Astrophysics
Volume575
DOIs
StatePublished - Mar 1 2015

Funding

We are grateful to Laura Sales for many useful discussions and to Carlos Vera-Ciro, Alvaro Villalobos and Volker Springel for providing code. AH acknowledges financial support from the European Research Council under ERC-StG grant GALACTICA-240271.

Keywords

  • Dark matter
  • Galaxies: dwarf
  • Galaxies: evolution
  • Galaxies: interactions
  • Galaxies: kinematics and dynamics
  • Galaxies: structure

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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