Environmental regulation of cloud and star formation in galactic bars

Research output: Contribution to journalArticle

Abstract

The strong time-dependence of the dynamics of galactic bars yields a complex and rapidly evolving distribution of dense gas and star forming regions. Although bars mainly host regions void of any star formation activity, their extremities can gather the physical conditions for the formation of molecular complexes and mini-starbursts. Using a sub-parsec resolution hydrodynamical simulation of a Milky Way-like galaxy, we probe these conditions to explore how and where bar (hydro-)dynamics favours the formation or destruction of molecular clouds and stars. The interplay between the kpc-scale dynamics (gas flows, shear) and the parsecscale (turbulence) is key to this problem. We find a strong dichotomy between the leading and trailing sides of the bar, in term of cloud fragmentation and in the age distribution of the young stars. After orbiting along the bar edge, these young structures slow down at the extremities of the bar, where orbital crowding increases the probability of cloud-cloud collision. We find that such events increase the Mach number of the cloud, leading to an enhanced star formation efficiency and finally the formation of massive stellar associations, in a fashion similar to galaxy-galaxy interactions. We highlight the role of bar dynamics in decoupling young stars from the clouds in which they form, and discuss the implications on the injection of feedback into the interstellar medium (ISM), in particular in the context of galaxy formation.

Details

Authors
  • F. Renaud
  • F. Bournaud
  • E. Emsellem
  • O. Agertz
  • E. Athanassoula
  • F. Combes
  • B. Elmegreen
  • K. Kraljic
  • F. Motte
  • R. Teyssier
External organisations
  • University of Surrey
  • Paris Diderot University
  • European Southern Observatory
  • Université Claude Bernard
  • Centre d'Ecologie Fonctionnelle et Evolutive (CEFE)
  • Laboratoire d'Études du Rayonnement et de la Matière en Astrophysique et Atmosphères (LERMA)
  • IBM Thomas J. Watson Research Center
  • University of Zurich
Research areas and keywords

Keywords

  • ISM: structure -Galaxy: structure, Methods: numerical
Original languageEnglish
Pages (from-to)3299-3310
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume454
Issue number3
Publication statusPublished - 2015 Dec 11
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes