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Interpreting the nature of starless cores has been a prominent goal in star formation for many years. In order to characterise the evolutionary stages of these objects, we perform synthetic observations of a numerical simulation of a…

Solar and Stellar Astrophysics · Physics 2015-06-18 Steve Mairs , Doug Johnstone , Stella S. R. Offner , Scott Schnee

The existence of substellar cold H2 globules in planetary nebulae and the mere existence of comets suggest that the physics of cold interstellar gas might be much richer than usually envisioned. We study the case of a cold gaseous medium in…

Astrophysics of Galaxies · Physics 2016-08-08 Andreas Füglistaler , Daniel Pfenniger

It has been known for more than 30 years that star formation in giant molecular clouds (GMCs) is slow, in the sense that only ~1% of the gas forms stars every free-fall time. This result is entirely independent of any particular model of…

Astrophysics · Physics 2008-11-26 Mark R. Krumholz , Jonathan C. Tan

N2H+ observations of molecular cloud cores in Taurus with the Nobeyama 45 m radio telescope are reported. We compare ``cores with young stars'' with ``cores without young stars''. The differences in core radius, linewidth, and core mass are…

Astrophysics · Physics 2009-11-10 K. Tatematsu , T. Umemoto , R. Kandori , Y. Sekimoto

We present a detailed computational study of the assembly of protostellar disks and massive stars in molecular clouds with supersonic turbulence. We follow the evolution of large scale filamentary structures in a cluster-forming clump down…

Astrophysics · Physics 2009-11-11 Robi Banerjee , Ralph E. Pudritz , Dave W. Anderson

The evolution of radiation emitted during the dynamical collapse of metal-free protostellar clouds is investigated within a spherically symmetric hydrodynamical scheme that includes the transfer of radiation and the chemistry of the…

Astrophysics · Physics 2009-11-06 Emanuele Ripamonti , Francesco Haardt , Andrea Ferrara , Monica Colpi

Clouds containing molecular dark matter in quantities relevant for star formation may exist in minihaloes of the type of cold dark matter included in many cosmological simulations or in the regions of some galaxies extending far beyond…

Astrophysics · Physics 2008-11-26 T. A. Bell , T. W. Hartquist , S. Viti , D. A. Williams

Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational…

Astrophysics · Physics 2009-11-10 Richard B. Larson

We investigate the Hierarchical Gravitational Fragmentation scenario through numerical simulations of the prestellar stages of the collapse of a marginally gravitationally unstable isothermal sphere immersed in a strongly gravitationally…

Astrophysics of Galaxies · Physics 2015-10-26 Raúl Naranjo-Romero , Enrique Vázquez-Semadeni , Robert M. Loughnane

We perform global linear stability analysis and idealized numerical simulations in global thermal balance to understand the condensation of cold gas from hot/virial atmospheres (coronae), in particular the intracluster medium (ICM). We pay…

Astrophysics of Galaxies · Physics 2016-02-15 Prakriti Pal Choudhury , Prateek Sharma

We derive models of rotating very massive stellar cores with mass $\approx 10^2$--$10^4M_\odot$ which are marginally stable to the pair-unstable collapse, assuming that the core is isentropic and composed primarily of oxygen. It is shown…

High Energy Astrophysical Phenomena · Physics 2025-09-22 Masaru Shibata , Sho Fujibayashi

The formation mechanism of massive stars remains one of the main open problems in astrophysics, in particular the relationship between the mass of the most massive stars, and that of the cores in which they form. Numerical simulations of…

Astrophysics of Galaxies · Physics 2024-02-16 Enrique Vázquez-Semadeni , Gilberto C. Gómez , Alejandro González-Samaniego

The efficiency of star formation, defined as the ratio of the stellar to total (gas and stellar) mass, is observed to vary from a few percent in regions of dispersed star formation to about a third in cluster-forming cores. This difference…

Astrophysics · Physics 2009-11-10 Fumitaka Nakamura , Zhi-Yun Li

Why do some clusters have cool cores while others do not? In this paper, cosmological simulations, including radiative cooling and heating, are used to examine the formation and evolution of cool core (CC) and non-cool core (NCC) clusters.…

Infrared Dark Clouds (IRDCs) are dense molecular clouds seen as extinction features against the bright mid-infrared Galactic background. Millimeter continuum maps toward 38 IRDCs reveal extended cold dust emission to be associated with each…

Astrophysics · Physics 2011-06-21 J. M. Rathborne , J. M. Jackson , R. Simon

We examined the gravitational contraction of isothermal molecular cloud cores with slow rotation by means of two-dimensional numerical simulations. Applying a sink-cell method, we followed the evolution of the cloud cores up to the stages…

Astrophysics · Physics 2009-10-31 Fumitaka Nakamura

To investigate how molecular clouds react to different environmental conditions at a galactic scale, we present a catalogue of giant molecular clouds resolved down to masses of $\sim 10$~M$_{\odot}$ from a simulation of the entire disc of…

We review recent advances in the analytical and numerical modeling of the star formation rate in molecular clouds and discuss the available observational constraints. We focus on molecular clouds as the fundamental star formation sites,…

Isolated low-mass stars are formed in dense cores of molecular clouds. In the standard picture, the cores are envisioned to condense out of strongly magnetized clouds through ambipolar diffusion. Most previous calculations based on this…

Astrophysics · Physics 2009-11-07 Zhi-Yun Li , Fumitaka Nakamura

We present a new model for the creation of cool cores in rich galaxy clusters within a LambdaCDM cosmological framework using the results from high spatial dynamic range, adaptive mesh hydro/N-body simulations. It is proposed that cores of…

Astrophysics · Physics 2007-05-23 J. O. Burns , P. M. Motl , M. L. Norman , G. L. Bryan
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