English
Related papers

Related papers: A Super-Alfvenic Model of Dark Clouds

200 papers

We show that it is possible to measure Alfv\'enic Mach numbers, defined as the shock velocity in the flow divided by the Alfv\'en velocity, for low-velocity (V$_{shock}$ $\lesssim$ 100 km$\,$s$^{-1}$) radiative shocks. The method combines…

Instrumentation and Methods for Astrophysics · Physics 2015-09-23 P. Hartigan , A. Wright

Plasma processes close to SNR shocks result in the amplification of magnetic fields and in the acceleration of electrons, injecting them into the diffusive acceleration mechanism. The acceleration of electrons and the B field amplification…

High Energy Astrophysical Phenomena · Physics 2015-06-09 M E Dieckmann , G Murphy , A Meli , L O C Drury

We analyse extinction maps of nearby Giant Molecular Clouds to forge a link between driving processes of turbulence and modes of star formation. Our investigation focuses on cloud structure in the column density range above the self…

Astrophysics of Galaxies · Physics 2015-05-28 J. Rowles , D. Froebrich

We show radio continuum images of several molecular complexes in the inner Galaxy and report the presence of dark features that coincide with dense molecular clouds. Unlike infrared dark clouds, these features which we call "radio dark…

Astrophysics of Galaxies · Physics 2015-06-11 F. Yusef-Zadeh

We investigate the formation of molecular clouds from atomic gas by using three-dimensional magnetohydrodynamic simulations, including non-equilibrium chemical reactions and heating/cooling processes. We consider super-Alfv\'enic head-on…

Astrophysics of Galaxies · Physics 2019-04-16 Kazunari Iwasaki , Kengo Tomida , Tsuyoshi Inoue , Shu-ichiro Inutsuka

We developed a magneto-turbulent model for the cosmic ray (CR) electrons seen in the radio halo clusters of galaxies. Steady state momentum distribution functions of the CR electrons are calculated for given spectra of the turbulent Alfven…

Astrophysics · Physics 2009-11-07 Hiroshi Ohno , Motokazu Takizawa , Shinpei Shibata

The molecular component of the Galaxy is comprised of turbulent, magnetized clouds, many of which are self-gravitating and form stars. To understand how these clouds' evolution may depend on their level of turbulence, mean magnetization,…

Astrophysics · Physics 2009-10-31 Eve C. Ostriker , Charles F. Gammie , James M. Stone

We determine the physical properties and turbulence driving mode of molecular clouds formed in numerical simulations of a Milky Way-type disc galaxy with parsec-scale resolution. The clouds form through gravitational fragmentation of the…

Astrophysics of Galaxies · Physics 2017-05-31 Keitaro Jin , Diane M. Salim , Christoph Federrath , Elizabeth J. Tasker , Asao Habe , Jouni T. Kainulainen

The turbulent destruction of a cloud subject to the passage of an adiabatic shock is studied. We find large discrepancies between the lifetime of the cloud and the analytical result of Hartquist et al. (1986). These differences appear to be…

Astrophysics of Galaxies · Physics 2015-05-18 J. M. Pittard , T. W. Hartquist , S. A. E. G. Falle

Alfv\'en vortex is a multi-scale nonlinear structure which contributes to intermittency of turbulence. Despite previous explorations mostly on the spatial properties of the Alfv\'en vortex (i.e., scale, orientation, and motion), the plasma…

We compare the statistical properties of J=1-0 13CO spectra observed in the Perseus Molecular Cloud with synthetic J=1-0 13CO spectra from a 5 pc model cloud. The synthetic spectra are computed solving the non-LTE radiative transfer problem…

Astrophysics · Physics 2007-05-23 Paolo Padoan , John Bally , Youssef Billawala , Mika Juvela , AAke Nordlund

Observations of nearby molecular clouds detect "shells", which are likely caused by winds from young main sequence stars. However, the progenitors of these observed features are not well characterized and the mass-loss rates inferred from…

Astrophysics of Galaxies · Physics 2015-10-07 S. S. R. Offner , H. G. Arce

M dwarf's atmosphere is expected to be highly magnetized. The magnetic energy can be responsible for heating the stellar chromosphere and corona, and driving the stellar wind. The nonlinear propagation of Alfv\'en wave is the promising…

Solar and Stellar Astrophysics · Physics 2021-09-29 Takahito Sakaue , Kazunari Shibata

Molecular clouds (MCs) are stellar nurseries, however, formation of stars within MCs depends on the ambient physical conditions. MCs, over a free-fall time are exposed to numerous dynamical phenomena, of which, the interaction with a thin,…

Astrophysics of Galaxies · Physics 2015-05-20 S. Anathpindika , H. C. Bhatt

Observed molecular clouds often appear to have very low star formation efficiencies and lifetimes an order of magnitude longer than their free-fall times. Their support is attributed to the random supersonic motions observed in them. We…

Astrophysics · Physics 2010-10-28 Ralf S. Klessen , Fabian Heitsch , Mordecai-Mark Mac Low

The center of the Milky Way galaxy (MW) is an extreme environment which contains a massive black hole surrounded by a very dense star cluster, two other adjacent star clusters, and a giant molecular cloud which would serve as an incubator…

Astrophysics of Galaxies · Physics 2015-06-03 Itzhak Goldman , Marcella Contini

We investigate, through a series of numerical calculations, the evolution of dense cores that are accreting external gas up to and beyond the point of star formation. Our model clouds are spherical, unmagnetized configurations with fixed…

Solar and Stellar Astrophysics · Physics 2015-06-16 Motahareh Mohammadpour , Steven W. Stahler

We study, by numerical simulations, the entrainment process in a supersonic, radiative jet flow, during the evolution of Kelvin-Helmholtz instabilities, in the context of the the acceleration problem of molecular bipolar outflows, observed…

Astrophysics · Physics 2007-05-23 M. Micono , G. Bodo , S. Massaglia , P. Rossi , A. Ferrari

Within ten nearby (d < 450 pc) Gould Belt molecular clouds we evaluate statistically the relative orientation between the magnetic field projected on the plane of sky, inferred from the polarized thermal emission of Galactic dust observed…

Astrophysics of Galaxies · Physics 2016-02-10 Planck Collaboration , P. A. R. Ade , N. Aghanim , M. I. R. Alves , M. Arnaud , D. Arzoumanian , M. Ashdown , J. Aumont , C. Baccigalupi , A. J. Banday , R. B. Barreiro , N. Bartolo , E. Battaner , K. Benabed , A. Benoît , A. Benoit-Lévy , J. -P. Bernard , M. Bersanelli , P. Bielewicz , J. J. Bock , L. Bonavera , J. R. Bond , J. Borrill , F. R. Bouchet , F. Boulanger , A. Bracco , C. Burigana , E. Calabrese , J. -F. Cardoso , A. Catalano , H. C. Chiang , P. R. Christensen , L. P. L. Colombo , C. Combet , F. Couchot , B. P. Crill , A. Curto , F. Cuttaia , L. Danese , R. D. Davies , R. J. Davis , P. de Bernardis , A. de Rosa , G. de Zotti , J. Delabrouille , C. Dickinson , J. M. Diego , H. Dole , S. Donzelli , O. Doré , M. Douspis , A. Ducout , X. Dupac , G. Efstathiou , F. Elsner , T. A. Enßlin , H. K. Eriksen , D. Falceta-Gonçalves , E. Falgarone , K. Ferrière , F. Finelli , O. Forni , M. Frailis , A. A. Fraisse , E. Franceschi , A. Frejsel , S. Galeotta , S. Galli , K. Ganga , T. Ghosh , M. Giard , E. Gjerløw , J. González-Nuevo , K. M. Górski , A. Gregorio , A. Gruppuso , J. E. Gudmundsson , V. Guillet , D. L. Harrison , G. Helou , P. Hennebelle , S. Henrot-Versillé , C. Hernández-Monteagudo , D. Herranz , S. R. Hildebrandt , E. Hivon , W. A. Holmes , A. Hornstrup , K. M. Huffenberger , G. Hurier , A. H. Jaffe , T. R. Jaffe , W. C. Jones , M. Juvela , E. Keihänen , R. Keskitalo , T. S. Kisner , J. Knoche , M. Kunz , H. Kurki-Suonio , G. Lagache , J. -M. Lamarre , A. Lasenby , M. Lattanzi , C. R. Lawrence , R. Leonardi , F. Levrier , M. Liguori , P. B. Lilje , M. Linden-Vørnle , M. López-Caniego , P. M. Lubin , J. F. Macías-Pérez , D. Maino , N. Mandolesi , A. Mangilli , M. Maris , P. G. Martin , E. Martínez-González , S. Masi , S. Matarrese , A. Melchiorri , L. Mendes , A. Mennella , M. Migliaccio , M. -A. Miville-Deschênes , A. Moneti , L. Montier , G. Morgante , D. Mortlock , D. Munshi , J. A. Murphy , P. Naselsky , F. Nati , C. B. Netterfield , F. Noviello , D. Novikov , I. Novikov , N. Oppermann , C. A. Oxborrow , L. Pagano , F. Pajot , R. Paladini , D. Paoletti , F. Pasian , L. Perotto , V. Pettorino , F. Piacentini , M. Piat , E. Pierpaoli , D. Pietrobon , S. Plaszczynski , E. Pointecouteau , G. Polenta , N. Ponthieu , G. W. Pratt , S. Prunet , J. -L. Puget , J. P. Rachen , M. Reinecke , M. Remazeilles , C. Renault , A. Renzi , I. Ristorcelli , G. Rocha , M. Rossetti , G. Roudier , J. A. Rubiño-Martín , B. Rusholme , M. Sandri , D. Santos , M. Savelainen , G. Savini , D. Scott , J. D. Soler , V. Stolyarov , R. Sudiwala , D. Sutton , A. -S. Suur-Uski , J. -F. Sygnet , J. A. Tauber , L. Terenzi , L. Toffolatti , M. Tomasi , M. Tristram , M. Tucci , G. Umana , L. Valenziano , J. Valiviita , B. Van Tent , P. Vielva , F. Villa , L. A. Wade , B. D. Wandelt , I. K. Wehus , N. Ysard , D. Yvon , A. Zonca

There are in the literature several theories to explain the mass loss in stellar winds. In particular, for late-type stars, some authors have proposed a wind model driven by an outward-directed flux of damped Alfven waves. The winds of…

Astrophysics · Physics 2009-11-13 A. A. Vidotto , V. Jatenco-Pereira