Related papers: The fragment mass scale of the primordial gas clou…
Subsequent to Paper I, the evolution and fragmentation of a rotating magnetized cloud are studied with use of three-dimensional MHD nested-grid simulations. After the isothermal runaway collapse, an adiabatic gas forms a protostellar first…
We study thermal-gravitational instability in simplified models for protogalactic halos using three-dimensional hydrodynamic simulations. The simulations followed the evolution of gas with radiative cooling down to T = 10^4 K, background…
The thermal and chemical evolution of star-forming clouds is studied for different gas metallicities, Z, using the model of Omukai (2000), updated to include deuterium chemistry and the effects of cosmic microwave background (CMB)…
We study numerically the effect of varying the equation of state (EOS) on the formation of stellar clusters in turbulent molecular clouds. Our results show that the EOS plays an important role in the fragmentation of the clouds, and the…
We model the coagulation and fragmentation of dust grains during the protostellar collapse with our newly developed shark code. It solves the gas-dust hydrodynamics in a spherical geometry and the coagulation/fragmentation equation. It also…
We use cosmological hydrodynamic simulations with unprecedented resolution to study the formation of primordial stars in an ionized gas at high redshifts. Our approach includes all the relevant atomic and molecular physics to follow the…
Observations reveal concentrations of molecular line emission on the sky, called ``clumps,'' in dense, star-forming molecular clouds. These clumps are believed to be the eventual sites of star formation. We study the three-dimensional…
The collapse and fragmentation of filamentary primordial gas clouds are explored using 1D and 2D hydrodynamical simulations coupled with the nonequilibrium processes of H2 formation. The simulations show that depending upon the initial…
In order to constrain the initial mass function (IMF) of the first generation of stars (Population III), we investigate the fragmentation properties of metal-free gas in the context of a hierarchical model of structure formation. We…
We derive the asymptotic mass profile near the collapse center of an initial spherical density perturbation, $\delta \propto M^{-\epsilon}$, of collision-less particles with non-radial motions. We show that angular momenta introduced at the…
We studied the gravitational collapse of a warm (~8000 K) primordial-gas cloud as a candidate progenitor for a supermassive star (SMS; >10^5 Msun) using a three-dimensional hydrodynamical simulation, including all the relevant cooling…
We investigate the origin of the observed scaling $j\sim R^{3/2}$ between the specific angular momentum $j$ and the radius $R$ of molecular clouds (MCs) and their their substructures, and of the observed near independence of $\beta$, the…
The observed rapid onset of star formation in molecular clouds requires rapid formation of dense fragments which can collapse individually before being overtaken by global gravitationally-driven flows. Many previous investigations have…
Angular momentum plays a crucial role in the formation of stars and planets. It has long been noticed that parcels of gas in molecular clouds need to reduce their specific angular momentum by 6 to 7 orders of magnitude to participate in the…
An attempt is made here to revisit structure formation in a proto-stellar cloud during the early phase of evolution. Molecular cloud subjected to a set of various initial conditions in terms of initial temperature and amplitude of azimuthal…
This short report is concerned with the well known and not yet satisfactorily answered problem of the existence of two well distinct typical mass scales of primordial halo objects: solar size objects (halo field stars) and globular cluster…
We investigate numerically and semi-analytically the collapse of low-mass, rotating prestellar cores. Initially, the cores are in approximate equilibrium with low rotation (the initial ratio of thermal to gravitational energy is $\alpha_0…
In order to constrain the initial mass function of the first generation of stars (Population III), one has to study the fragmentation properties of primordial gas. We present results from 3D simulations, based on Smoothed Particle…
Shocks may have been prevalent in the early Universe, associated with virialization and supernova explosions, etc. Here, we study thermal evolution and fragmentation of shock-compressed clouds, by using a one-zone model with detailed…
Clouds more massive than about $10^5$ M$_\odot$ are potential sites of massive cluster formation. Studying the properties of such clouds in the early stages of their evolution offers an opportunity to test various cluster formation…