From the warm magnetized atomic medium to molecular clouds

By P. Hennebelle, Robi Banerjee, E. Vázquez-Semadeni, Ralf Klessen, E. Audit. 2008

185 citations recorded by the source corpus.

Context. It has been proposed that giant molecular complexes form at the sites of streams of diffuse warm atomic gas that collide at transonic velocities. Aims. We study the global statistics of molecular clouds formed by large scale colliding flows of warm neutral atomic interstellar gas under pure hydrodynamic and ideal MHD conditions. The flows deliver material as well as kinetic energy and trigger thermal instability leading eventually to gravitational collapse. Methods. We perform adaptive mesh refinement MHD simulations that, for the first time in this context, treat cooling and self-gravity self-consistently. Results. The clouds formed in the simulations develop a highly inhomogeneous density and temperature structure, with cold dense filaments and clumps condensing from converging flows of warm atomic gas. In the clouds, the column density probability density distribution (PDF) peaks at ~ 2 $\times$ 10 21 cm -2 and decays rapidly at higher values; the magnetic intensity correlates weakly with density between n ~ 0.1 and 10 4 cm -3 , and then varies roughly as $n^{1/2}$ for higher densities. Conclusions. The global statistical properties of such molecular clouds are reasonably consistent with observational measurements. Our numerical simulations suggest that molecular clouds form by the moderately supersonic collision of warm atomic gas streams.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/86d64c44ef2a5d3faf0aa7d14b220695ae5d70ac

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Citations in the corpus

The Formation and Destruction of Molecular Clouds and Galactic Star Formation (2015, background): “…density, this formation timescale is shorter than that of molecular cloud formation solely through the accumulation of diffuse WNM (see, e.g., Koyama & Inutsuka 2002; Hennebelle et al. 2008; Heitsch & Hartmann 2008; Banerjee et al. 2009; Vázquez-Semadeni et al. 2011, for the cases of WNM flows).”
Clump morphology and evolution in MHD simulations of molecular cloud formation (2008, methodology): “…image one can see that the “cloud” is not a homogeneous entity, but rather it is composed of dense clumps (which should be mostly molecular) embedded in somewhat less dense filaments (which may be partly molecular and partly atomic) (see also Vázquez-Semadeni et al. 2007; Hennebelle et al. 2008).”
TURBULENCE AND MAGNETIC FIELD AMPLIFICATION IN SUPERNOVA REMNANTS: INTERACTIONS BETWEEN A STRONG SHOCK WAVE AND MULTIPHASE INTERSTELLAR MEDIUM (2009, background): “In particular, huge amounts of HI CNM clumps are expected around molecular clouds (see, e.g. Blitz et al. 2006 for observation and Koyama & Inutsuka 2002; Inoue & Inutsuka 2008; Hennebelle et al. 2008 and Heitsch et al. 2008 for simulations of molecular cloud formation).”
Cores, filaments, and bundles: hierarchical core formation in the L1495/B213 Taurus region (2013, background): “This however is not necessarily so if the L1495/B213 complex was formed by the convergence of large-scale flows, a mechanism favored by a number of theoretical considerations and numerical simulations (e.g., Elmegreen 1993; Vázquez-Semadeni et al. 2006; Hennebelle et al. 2008; Heitsch et al. 2008).”
TOWARD UNDERSTANDING THE COSMIC-RAY ACCELERATION AT YOUNG SUPERNOVA REMNANTS INTERACTING WITH INTERSTELLAR CLOUDS: POSSIBLE APPLICATIONS TO RX J1713.7−3946 (2011, background): “…clouds are formed as a complex of clumps fragmented by the thermal instability that are embedded in diffuse gas (Koyama & Inutsuka 2002; Hennebelle et al. 2008; Inoue & Inutsuka 2008; 2009; Banerjee et al. 2009; Heitsch et al. 2009; VázquezSemadeni et al. 2006, Audit & Hennebelle 2010).”
Accretion-driven turbulence as universal process: galaxies, molecular clouds, and protostellar disks (2009, methodology): “…accretion energy is converted into turbulent energy we resort to numerical simulations of converging flows (e.g. Audit & Hennebelle 2005; Heitsch et al. 2005, 2006a; Folini & Walder 2006; Vázquez-Semadeni et al. 2006, 2007; Hennebelle et al. 2008; Banerjee et al. 2009; Audit & Hennebelle 2010).”
ANALYTICAL THEORY FOR THE INITIAL MASS FUNCTION. II. PROPERTIES OF THE FLOW (2009, background): “Finally, it sounds likely that gravity will also lead to a similar effect with the high density tail of the PDF becoming less stiff and more extended (Klessen 2000, Vázquez-Semadeni et al. 2008, Hennebelle et al. 2008).”
Turbulent molecular clouds (2012, methodology): “In the second step, gravity has been introduced therefore letting the condensations to proceed further (Vázquez–Semadeni et al. 2008, Heitsch et al. 2008, Hennebelle et al. 2008, Banerjee et al. 2009).”
Comparing the statistics of interstellar turbulence in simulations and observations - Solenoidal versus compressive turbulence forcing (2009, background): “5 http://www.ita.uni-heidelberg.de/ chfeder/videos.shtml?lang=en (e.g., Heitsch et al. 2006; Vázquez-Semadeni et al. 2006; Hennebelle et al. 2008; Banerjee et al. 2008) are more suitable for studying the boundary effects during the formation of molecular clouds.”
A NEW JEANS RESOLUTION CRITERION FOR (M)HD SIMULATIONS OF SELF-GRAVITATING GAS: APPLICATION TO MAGNETIC FIELD AMPLIFICATION BY GRAVITY-DRIVEN TURBULENCE (2011, background): “…massive star clusters (Mac Low & Klessen 2004; Schneider et al. 2010), and the galactic spiral shock, producing large-scale converging flows (Vishniac 1994; Walder & Folini 1996; VázquezSemadeni et al. 2006; Heitsch et al. 2006; Hennebelle et al. 2008; Banerjee et al. 2009; Folini et al. 2010).”
Modelling CO formation in the turbulent interstellar medium (2009, background): “…& Pérault 1999, 2000; Koyama & Inutsuka 2000, 2002; Bergin et al. 2004) or on a detailed treatment of the dynamics, but without any treatment of the chemistry (e.g. Balsara et al. 2004; Kritsuk & Norman 2004; Slyz et al. 2005; Hennebelle & Audit 2007; Hennebelle et al. 2008; Banerjee et al. 2009).”
AN IMPRINT OF MOLECULAR CLOUD MAGNETIZATION IN THE MORPHOLOGY OF THE DUST POLARIZED EMISSION (2013, methodology): “Nevertheless, the HRO analysis can be extended to simulations including more complex realizations of molecular clouds (Nakamura & Li 2008; Hennebelle et al. 2008).”
Global hierarchical collapse in molecular clouds. Towards a comprehensive scenario (2019, unknown): “…through their gravitational contraction, as done in converging-flow simulations (e.g. Vázquez-Semadeni et al. 2007, 2010; Heitsch & Hartmann 2008; Hennebelle et al. 2008; Banerjee et al. 2009; Coĺın et al. 2013; Carroll-Nellenback et al. 2014; Körtgen et al. 2016; Wareing et al. 2017a;…”
Dynamic star formation in the massive DR21 filament (2010, background): “…2010) within large-scale colliding flows of mostly atomic gas in the galactic disk, generated by dynamic compression in the interstellar medium or other large-scale instabilities (see, e.g., Hennebelle & Audit 2007, Vazquez-Semadeni et al. 2008, Hennebelle et al. 2008, Banerjee et al. 2009).”