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Using the spherical collapse approach, we investigate the impact of two alternative dark matter models, each characterized by distinct non-zero equations of state, one constant and the other time dependent on the nonlinear regime.…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-22 Zahra Davari , Amjad Ashoorioon , Kazem Rezazadeh

Accumulating observational evidence for a number of radio galaxies suggests an association between their jets and regions of active star formation. The standard picture is that shocks generated by the jet propagate through an inhomogeneous…

Astrophysics · Physics 2009-11-10 P. Chris Fragile , Stephen D. Murray , Peter Anninos , Wil van Breugel

The distribution of protostar masses is studied for core-environment systems whose duration of infall follows a waiting-time distribution. Each core-environment system has a continuous density profile with no barrier to mass flow. The core…

Astrophysics of Galaxies · Physics 2014-11-20 Philip C. Myers

The formation and collapse of a protostar involves the simultaneous infall and outflow of material in the presence of magnetic fields, self-gravity, and rotation. We use self-similar techniques to self-consistently model the anisotropic…

Astrophysics · Physics 2016-01-13 Mahmoud Aburihan , Jason D. Fiege , Richard N. Henriksen , Thibaut Lery

Dynamical collapses of magnetized molecular cloud cores are studied with magnetohydrodynamical simulations from the run-away collapse phase to the accretion phase. In the run-away collapse phase, a disk threaded by magnetic field lines is…

Astrophysics · Physics 2009-10-30 Kohji Tomisaka

The collapse of dense cores with different metallicities is studied by hydrodynamical calculations coupled with detailed chemical and radiative processes. For this purpose, we construct a simple chemical network with non-equilibrium…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Kazuyuki Omukai , Takashi Hosokawa , Naoki Yoshida

We explore whether observed molecular clouds could include a substantial population of unbound clouds. Using simulations which include only turbulence and gravity, we are able to match observed relations and naturally reproduce the observed…

Astrophysics of Galaxies · Physics 2014-03-05 Rachel L. Ward , James Wadsley , Alison Sills

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,…

We perform a non-radial adiabatic perturbation analysis on homologous conventional polytropic stellar core collapses. The core collapse features a polytropic exponent $\Gamma=4/3$ relativistic gas under self-gravity of spherical symmetry…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Yi Cao , Yu-Qing Lou

We study the formation of H2 in the ISM, using a modified version of the astrophysical magnetohydrodynamical code ZEUS-MP that includes a non-equilibrium treatment of the formation and destruction of H2. We examine two different…

Astrophysics · Physics 2008-11-26 S. C. O. Glover , M. -M. Mac Low

We present results from the first three-dimensional calculations ever to follow the collapse of a molecular cloud core (~ 10^{-18} g cm^{-3}) to stellar densities (> 0.01 g cm^{-3}). The calculations resolve structures over 7 orders of…

Astrophysics · Physics 2009-10-31 Matthew R. Bate

The evolutionary sequence for high-mass star formation starts with massive starless clumps that go on to form protostellar, young stellar objects and then compact HII regions. While there are many examples of the three later stages, the…

Astrophysics of Galaxies · Physics 2023-05-09 T. G. S. Pillai , J. S. Urquhart , S. Leurini , Q. Zhang , A. Traficante , D. Colombo , K. Wang , L. Gomez , F. Wyrowski

Under the assumptions that molecular clouds are nearly spatially and temporally isothermal and that the density peaks (``cores'') within them are formed by turbulent fluctuations, we argue that cores cannot reach a hydrostatic (or…

We analyze the problem of gravitational collapse considering the matching of an exterior region described by the Vaidya's metric and an interior region described by a spherically symmetric shear-free inhomogeneous geometry sourced by a…

General Relativity and Quantum Cosmology · Physics 2026-02-25 Eduardo Bittencourt , Vanessa P Freitas , José M Salim , Grasiele B Santos

We present a detailed parameter study of collapsing turbulent cloud cores, varying the initial density profile and the initial turbulent velocity field. We systematically investigate the influence of different initial conditions on the star…

Solar and Stellar Astrophysics · Physics 2015-05-19 Philipp Girichidis , Christoph Federrath , Robi Banerjee , Ralf S. Klessen

We present results from the first 2+1 and 3+1 simulations of the collapse of rotating stellar iron cores in general relativity employing a finite-temperature equation of state and an approximate treatment of deleptonization during collapse.…

We simulate fragmentation and gravitational collapse of cold, magnetized molecular clouds. We explore the nonlinear development of an instability mediated by ambipolar diffusion, in which the collapse rate is intermediate to fast…

Astrophysics · Physics 2009-10-31 R. Indebetouw , E. G. Zweibel

In this study, the main goal is to understand the molecular cloud core collapse through the stages of first and second hydrostatic core formation. We investigate the properties of Larson's first and second cores following the evolution of…

Solar and Stellar Astrophysics · Physics 2018-10-24 Asmita Bhandare , Rolf Kuiper , Thomas Henning , Christian Fendt , Gabriel-Dominique Marleau , Anders Kölligan

The thermal and chemical evolution of gravitationally collapsing protostellar clouds is investigated, focusing attention on their dependence on metallicity. Calculations are carried out for a range of metallicities spanning the local…

Astrophysics · Physics 2009-10-31 Kazuyuki Omukai

In a previous paper we introduced a new method for simulating collisional gravitational $N$-body systems with linear time scaling on $N$, based on the Multi-Particle Collision (MPC) approach. This allows us to simulate globular clusters…

Astrophysics of Galaxies · Physics 2022-03-04 Pierfrancesco Di Cintio , Mario Pasquato , Alicia Simon-Petit , Suk-Jin Yoon