Detalles de publicación
PP 025091
Extreme cloud collisions in nearby barred galaxies
1 School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
2 Astrophysics Research Institute, Liverpool John Moores University, IC2 Liverpool Science Park, 146 Brownlow Hill, L3 5RF, UK
3 Como Lake centre for AstroPhysics (CLAP), DiSAT, Universit`a dell’Insubria, via Valleggio 11, 22100 Como, Italy
4 Max-Planck-Institut f¨ur Astronomie, K¨onigstuhl 17, 69117 Heidelberg, Germany
5 Institute for Computational Cosmology, Department of Physics, Durham University, DH1 3LE, United Kingdom
6 European Southern Observatory, Karl-Schwarzschild 2, 85748 Garching bei Muenchen, Germany
7 Argelander-Institut f¨ur Astronomie, Universit¨at Bonn, Auf dem H¨ugel 71, 53121 Bonn, Germany
8 Institut f¨ur Theoretische Astrophysik, Zentrum f¨ur Astronomie der Universit¨at Heidelberg, Albert-Ueberle-Strasse 2, 69120
Heidelberg, Germany
9 Cosmic Origins Of Life (COOL) Research DAO, coolresearch.io
10 Univ Lyon, Univ Lyon 1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon UMR5574, 69230 Saint-Genis-Laval, France
11 Universit¨at Heidelberg, Interdisziplin¨ares Zentrum f¨ur Wissenschaftliches Rechnen, Im Neuenheimer Feld 225, 69120,
Heidelberg, Germany
12 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, U.S.A
13 Elizabeth S. and Richard M. Cashin Fellow at Radcliffe Institute for Advanced Studies at Harvard University, 10 Garden Street, Cambridge, MA
14 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent, Belgium
15 Instituto de Astrof´ısica de Canarias, C/ V´ıa L´actea s/n, E-38205, La Laguna, Spain
16 Departamento de Astrof´ısica, Universidad de La Laguna, Av. del Astrof´ısico Francisco S´anchez s/n, E-38206, La Laguna, Spain
17 Observatorio Astron´omico Nacional (IGN), C/Alfonso XII 3, Madrid 28014, Spain
18 Sub-department of Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH, UK
Abstract:The inner regions of the Milky Way are known to contain an enigmatic population of prominent molecular clouds characterised by extremely broad lines. The physical origin of these ''extended velocity features'' (EVFs) is still debated, although a connection with the ''dust lanes'' of the Galactic bar has been hypothesised. In this paper, we search for analogous features in the dust lanes of nearby barred galaxies using the PHANGS-ALMA CO(2-1) survey. We aim to confirm existence of EVFs in other galaxies and to take advantage of the external perspective to gain insight into their origin. We study a sample of 29 barred galaxies and find that 34% contain one or more EVFs, while the remaining lack obvious signs of EVFs. Upon analysing the physical properties of the EVFs, we find they possess large virial parameters, ranging from few hundreds to several thousand, indicating that they are strongly out-of-equilibrium. The most likely explanation for their origin is extreme cloud-cloud collisions with relative velocities in excess of 100km/s in highly non-circular flow driven by the bar. This interpretation is consistent with previous high-resolution observations in Milky Way. Further corroboration of this interpretation comes from the inspection of high-sensitivity infrared observations from the PHANGS-JWST Treasury Survey that reveals streams of gas that appear to be hitting the dust lanes at locations where EVFs are found. We argue that EVFs are the clearest examples of cloud-cloud collisions available in literature and represent a unique opportunity to study cloud collisions and their impact on star formation.