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Related papers: Molecular Cloud Evolution VI. Measuring cloud ages

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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…

Astrophysics of Galaxies · Physics 2015-05-28 Manuel Zamora-Aviles , Enrique Vázquez-Semadeni , Pedro Colín

We discuss the dependence of various properties of the star formation rate (SFR) and efficiency (SFE) in molecular clouds (MCs) on the maximum mass reached by the clouds, based on a previously-published model for MC and SFR evolution in…

Solar and Stellar Astrophysics · Physics 2015-06-17 Manuel Zamora-Avilés , Enrique Vázquez-Semadeni

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…

Astrophysics of Galaxies · Physics 2010-09-22 Enrique Vazquez-Semadeni

Most young stars in nearby molecular clouds have estimated ages of 1-2 Myr, suggesting that star formation is rapid. However, small numbers of stars in these regions with inferred ages of >= 5-10 Myr have been cited to argue that star…

Solar and Stellar Astrophysics · Physics 2015-06-03 Lee Hartmann , Javier Ballesteros-Paredes , Fabian Heitsch

The gravitational binding and star-forming properties of molecular clouds (MCs) in the Milky Way (MW) are estimated from CO cloud observations and from a model of pressure-bounded virial equilibrium (PVE). Two CO surveys are analyzed with…

Astrophysics of Galaxies · Physics 2025-08-11 Philip C. Myers , Mark Heyer , Ian W. Stephens , Simon Coudé , Nicole Karnath , Howard A. Smith

We investigate the formation and evolution of giant molecular clouds (GMCs) by the collision of convergent warm neutral medium (WNM) streams in the interstellar medium, in the presence of magnetic fields and ambipolar diffusion (AD),…

The star formation efficiency (SFE) measures the proportion of molecular gas converted into stars, while the star formation rate (SFR) indicates the rate at which gas is transformed into stars. Here we propose such a model in the framework…

Astrophysics of Galaxies · Physics 2025-02-25 An-Xu Luo , Hong-Li Liu , Jin-Zeng Li

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…

We present a numerical study of the evolution of molecular clouds, from their formation by converging flows in the warm ISM, to their destruction by the ionizing feedback of the massive stars they form. We improve with respect to our…

Astrophysics of Galaxies · Physics 2015-06-15 Pedro Colin , Enrique Vazquez-Semadeni , Gilberto C. Gomez

We present an analysis of Giant Molecular Clouds (GMCs) within hydrodynamic simulations of isolated, low-mass (M* ~ 10^9 M_sol) disc galaxies. We study the evolution of molecular abundances and the implications for CO emission and the X_CO…

Astrophysics of Galaxies · Physics 2016-07-27 Alexander J. Richings , Joop Schaye

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…

Astrophysics of Galaxies · Physics 2015-05-14 Enrique Vazquez-Semadeni , Pedro Colin , Gilberto C. Gomez , Alan Watson

We present a detailed study of the evolution of GMCs in a galactic disc simulation. We follow individual GMCs (defined in our simulations by a total column density criterion), including their level of star formation, from their formation to…

Astrophysics of Galaxies · Physics 2015-06-15 C. L. Dobbs , J. E. Pringle

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…

Astrophysics of Galaxies · Physics 2015-05-28 Nathan J. Goldbaum , Mark R. Krumholz , Christopher D. Matzner , Christopher F. McKee

We construct a model by integrating observational constraints from the Milky Way and nearby galaxies to predict cloud-scale star formation rates (SFRs). In the model, we first estimate the initial total mass of clumps in a cloud based on…

Astrophysics of Galaxies · Physics 2026-02-10 J. W. Zhou , Amelie Saintonge , Sami Dib , Pavel Kroupa

The processes of star formation and feedback, regulating the cycle of matter between gas and stars on the scales of giant molecular clouds (GMCs; $\sim$100pc), play a major role in governing galaxy evolution. Measuring the time-scales of…

Giant molecular clouds (GMCs) are well-studied in the local Universe, however, exactly how their properties vary during galaxy evolution is poorly understood due to challenging resolution requirements, both observational and computational.…

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…

Astrophysics of Galaxies · Physics 2016-04-26 Todor V. Veltchev , Sava Donkov , Ralf S. Klessen

In this work, we trace the complete life cycle of individual GMCs in high-resolution Milky Way-mass galaxy simulations to determine how different stellar feedback mechanisms and galactic-scale processes govern cloud lifetimes, mass…

Astrophysics of Galaxies · Physics 2025-07-22 Yang Ni , Hui Li , Mark Vogelsberger , Laura V. Sales , Federico Marinacci , Paul Torrey

We analyze the first giant molecular cloud (GMC) simulation to follow the formation of individual stars and their feedback from jets, radiation, winds, and supernovae, using the STARFORGE framework in the GIZMO code. We evolve the GMC for…

Molecular clouds are supported by turbulence and magnetic fields, but quantifying their influence on cloud lifecycle and star formation efficiency (SFE) remains an open question. We perform radiation MHD simulations of star-forming giant…

Astrophysics of Galaxies · Physics 2021-05-05 Jeong-Gyu Kim , Eve C. Ostriker , Nina Filippova
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