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The evolution of molecular clouds in galactic centres is thought to differ from that in galactic discs due to a significant influence of the external gravitational potential. We present a set of numerical simulations of molecular clouds…

We present virial models for the global evolution of giant molecular clouds. Focusing on the presence of an accretion flow, and accounting for the amount of mass, momentum, and energy supplied by accretion and star formation feedback, we…

星系天体物理 · 物理学 2015-05-28 Nathan J. Goldbaum , Mark R. Krumholz , Christopher D. Matzner , Christopher F. McKee

We present a model for describing the general structure of molecular clouds (MCs) at early evolutionary stages in terms of their mass-size relationship. Sizes are defined through threshold levels at which equipartitions between…

星系天体物理 · 物理学 2016-04-26 Todor V. Veltchev , Sava Donkov , Ralf S. Klessen

I describe the scenario of molecular cloud (MC) evolution that has emerged over the past decade or so. MCs can start out as cold atomic clouds formed by compressive motions in the warm neutral medium (WNM) of galaxies. Such motions can be…

星系天体物理 · 物理学 2010-09-22 Enrique Vazquez-Semadeni

Molecular clouds (MC) are structures of dense gas in the interstellar medium (ISM), that extend from ten to a few hundred parsecs and form the main gas reservoir available for star formation. Hydrodynamical simulations of varying complexity…

We study the formation of giant dense cloud complexes and of stars within them by means of SPH numerical simulations of the mildly supersonic collision of gas streams (``inflows'') in the warm neutral medium (WNM). The resulting…

Aims: We derive the probability density functions (PDFs) of column density for a complete sample of prominent molecular cloud complexes closer than 200 pc. Methods: We derive near-infrared dust extinction maps for 23 molecular cloud…

星系天体物理 · 物理学 2015-05-14 J. Kainulainen , H. Beuther , T. Henning , R. Plume

We recently proposed that the star-forming potential of dense molecular clouds in the Central Molecular Zone (CMZ, i.e. the central few 100 pc) of the Milky Way is linked to their orbital dynamics, potentially giving rise to an…

星系天体物理 · 物理学 2015-06-23 J. M. Diederik Kruijssen , James E. Dale , Steven N. Longmore

We present an idealized, semi-empirical model for the evolution of gravitationally contracting molecular clouds (MCs) and their star formation rate (SFR) and efficiency (SFE). The model assumes that the instantaneous SFR is given by the…

星系天体物理 · 物理学 2015-05-28 Manuel Zamora-Aviles , Enrique Vázquez-Semadeni , Pedro Colín

In this paper we continue to investigate the energy conservation equation obtained in our previous work. We set ourselves three new goals. The first one is to rewrite the main equations in terms of density profile in order to give more…

星系天体物理 · 物理学 2019-03-27 Sava Donkov , Ivan Zh. Stefanov

We numerically investigate the effect of feedback from the ionizing radiation heating from massive stars on the evolution of giant molecular clouds (GMCs) and their star formation efficiency (SFE). We find that the star-forming regions…

星系天体物理 · 物理学 2015-05-14 Enrique Vazquez-Semadeni , Pedro Colin , Gilberto C. Gomez , Alan Watson

We compile a holistic scenario for molecular cloud (MC) evolution and control of the star formation efficiency (SFE), and present a first set of numerical tests of it. A {\it lossy} compressible cascade can generate density fluctuations and…

天体物理学 · 物理学 2009-11-07 E. Vazquez-Semadeni , J. Ballesteros-Paredes , R. S. Klessen

The asymmetric molecular emission lines from dense cores reveal slow, inward motion in the clouds' outer regions. This motion is present both before and after the formation of a central star. Motivated by these observations, we revisit the…

太阳与恒星天体物理 · 物理学 2015-06-05 Paul A. Dalba , Steven W. Stahler

High-Velocity Clouds (HVCs) are a major fuel reservoir for star formation in the Galactic disk. Determining their origin and kinematics is thus crucial for understanding Galactic evolution. In this paper, we employ simple test-particle…

星系天体物理 · 物理学 2026-04-28 Izumi Seno , Shu-ichiro Inutsuka , Jiro Shimoda

High-mass stars have an enormous influence on the evolution of the interstellar medium in galaxies, so it is important that we understand how they form. We examine the central clumps within a sample of seven infrared-dark clouds (IRDCs)…

We present an idealized, spherical model of the evolution of a magnetized molecular cloud due to ambipolar diffusion. This model allows us to follow the quasi-static evolution of the cloud's core prior to collapse and the subsequent…

天体物理学 · 物理学 2009-10-30 P. N. Safier , C. F. McKee , S. W. Stahler

Magnetic clouds (MCs) are "magnetized plasma clouds" moving in the solar wind. MCs transport magnetic flux and helicity away from the Sun. These structures are not stationary but feature temporal evolution. Commonly, simplified MC models…

太阳与恒星天体物理 · 物理学 2015-05-20 Giorgi Dalakishvili , Andria Rogava , Giovanni Lapenta , Stefaan Poedts

We perform a suite of hydrodynamic simulations to investigate how initial density profiles of giant molecular clouds (GMCs) affect their subsequent evolution. We find that the star formation duration and integrated star formation efficiency…

星系天体物理 · 物理学 2021-03-03 Yingtian Chen , Hui Li , Mark Vogelsberger

Molecular clouds (MCs) are the birthplaces of new stars in galaxies. A key component of MCs are photodissociation regions (PDRs), where far-ultraviolet radiation plays a crucial role in determining the gas's physical and chemical state.…

We formulate the problem of the late accretion phase of the evolution of an isothermal magnetic disk surrounding a forming star. The evolution is described by the six-fluid MHD equations, accounting for the presence of neutrals, atomic and…

天体物理学 · 物理学 2009-11-10 Konstantinos Tassis , Telemachos Ch. Mouschovias
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