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dc.contributor.authorFalceta-Goncalves, D.
dc.contributor.authorBonnell, I.
dc.contributor.authorKowal, G.
dc.contributor.authorLepine, J. R. D.
dc.contributor.authorBraga, C. A. S.
dc.identifier.citationFalceta-Goncalves , D , Bonnell , I , Kowal , G , Lepine , J R D & Braga , C A S 2015 , ' The onset of large-scale turbulence in the interstellar medium of spiral galaxies ' , Monthly Notices of the Royal Astronomical Society , vol. 446 , no. 1 , pp. 973-989 .
dc.descriptionDFG thanks the European Research Council (ADG-2011 ECOGAL), and Brazilian agencies CAPES (3400-13-1) and FAPESP (no.2011/12909-8) for financial support. IB acknowledges the European Research Council (ADG-2011 ECOGAL) for financial support. GK acknowledges support from FAPESP (grants no. 2013/04073-2 and 2013/18815-0).en
dc.description.abstractTurbulence is ubiquitous in the interstellar medium (ISM) of the Milky Way and other spiral galaxies. The energy source for this turbulence has been much debated with many possible origins proposed. The universality of turbulence, its reported large-scale driving, and that it occurs also in starless molecular clouds, challenges models invoking any stellar source. A more general process is needed to explain the observations. In this work, we study the role of galactic spiral arms. This is accomplished by means of three-dimensional hydrodynamical simulations which follow the dynamical evolution of interstellar diffuse clouds (similar to 100 cm-3) interacting with the gravitational potential field of the spiral pattern. We find that the tidal effects of the arm's potential on the cloud result in internal vorticity, fragmentation and hydrodynamical instabilities. The triggered turbulence results in large-scale driving, on sizes of the ISM inhomogeneities, i.e. as large as similar to 100 pc, and efficiencies in converting potential energy into turbulence in the range similar to 10-25 per cent per arm crossing. This efficiency is much higher than those found in previous models. The statistics of the turbulence in our simulations are strikingly similar to the observed power spectrum and Larson scaling relations of molecular clouds and the general ISM. The dependence found from different models indicate that the ISM turbulence is mainly related to local spiral arm properties, such as its mass density and width. This correlation seems in agreement with recent high angular resolution observations of spiral galaxies, e.g. M51 and M33.
dc.relation.ispartofMonthly Notices of the Royal Astronomical Societyen
dc.subjectMethods: numericalen
dc.subjectStars: formationen
dc.subjectISM: cloudsen
dc.subjectISM: generalen
dc.subjectISM: kinematics and dynamicsen
dc.subjectGiant molecular cloudsen
dc.subjectSupersonic turbulenceen
dc.subjectVelocity fielden
dc.subjectGalactic disksen
dc.subjectMagnetohydrodynamic turbulenceen
dc.subject2-dimensional turbulenceen
dc.subjectNumerical simulationsen
dc.subjectWiggle instabilityen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleThe onset of large-scale turbulence in the interstellar medium of spiral galaxiesen
dc.typeJournal articleen
dc.contributor.sponsorEuropean Research Councilen
dc.contributor.sponsorScience & Technology Facilities Councilen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.description.statusPeer revieweden

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