相关论文: Large Scale Dynamo in a Primordial Accretion Flow …
Magnetic fields are usually considered dynamically important in star formation when the dimensionless mass-to-flux ratio is close to, or less than, unity (lambda<~1). We show that, in disk formation, the requirement is far less stringent.…
We posit that accreting compact objects, including stellar mass black holes and neutron stars as well as supermassive black holes, may undergo extended periods of accretion during which the angular momentum of the disk at large scales is…
Fragmentation of highly differentially rotating massive stars that undergo collapse has been suggested as a possible channel for binary black hole formation. Such a scenario could explain the formation of the new population of massive black…
Aims. We investigate the cosmological evolution of large- and small-scale magnetic fields in galaxies in the light of present models of formation and evolution of galaxies. Methods. We use the dynamo theory to derive the timescales of…
We present results of fully three-dimensional MHD simulations of disk accretion to a rotating magnetized star with its dipole moment inclined at an angle Theta to the rotation axis of the disk. We observed that matter accretes from the disk…
Buoyancy of the fossil magnetic field in the accretion disks of young stars is investigated. It is assumed that the Parker instability leads to the formation of slender flux tubes of toroidal magnetic field in the regions of effective…
We investigate hydromagnetic turbulence of primordial magnetic fields using magnetohydrodynamics (MHD) in an expanding universe. We present the basic, covariant MHD equations, find solutions for MHD waves in the early universe, and…
The first stars might have been fast rotators. This would have important consequences for their radiative, mechanical and chemical feedback. We discuss the impact of fast initial rotation on the evolution of massive Population III models…
We present results of global three-dimensional (3D) magnetohydrodynamic (MHD) simulations of accretion onto magnetized stars where both the magnetic and rotational axes of the star are tilted about the rotational axis of the disc. We…
Our understanding of the dynamical processes which control the structure and evolution of the interaction region between an accretion disk and the central star is reviewed. If the central star is unmagnetized, this interaction is in the…
We investigate numerically magnetic field generation by thermal convection with square periodicity cells in a rotating horizontal layer of electrically-conducting fluid with stress-free electrically perfectly conducting boundaries for…
Direct collapse of supermassive stars is a possible pathway to form supermassive black hole seeds at high redshifts. Whereas previous three-dimensional (3D) simulations demonstrate that supermassive stars form via rapid mass accretion,…
We combine the output of hydrodynamical simulations of Population III star cluster formation with stellar evolution models, and calculate the evolution of protostars experiencing variable mass accretion rates due to interactions within a…
Disk galaxies are in hydrostatic equilibrium along their vertical axis. The pressure allowing for this configuration consists of thermal, turbulent, magnetic and cosmic ray components. For the Milky Way(MW) the thermal pressure contributes…
We investigate the fossil magnetic field in the accretion and protoplanetary discs using the Shakura and Sunyaev approach. The distinguishing feature of this study is the accurate solution of the ionization balance equations and the…
We study a Jupiter-mass planet formation for the first time in radiative magneto-hydrodynamics (MHD) simulations and compare it with pure hydrodynamical simulations, as well as to different isothermal configurations. We found that the…
Recent observations have detected excess H$\alpha$ emission from young stellar systems with an age of several Myr such as PDS 70. One-dimensional radiation-hydrodynamic models of shock-heated flows that we developed previously demonstrate…
There is still much uncertainty around the mechanism that rules the accretion of proto-planetary disks. In the last years, Magnetohydrondynamic (MHD) wind-driven accretion has been proposed as a valid alternative to the more conventional…
A simple model of gas accretion in young galaxy disks suggests that fast turbulent motions can be driven by accretion energy for a time t_acc~2(epsilon^{0.5} GM^2/xi V^3)^{0.5} where epsilon is the fraction of the accretion energy going…
Recent high-sensitivity observations reveal that accreting giant planets embedded in their parental circumstellar disks can emit H$\alpha$ at their final formation stages. While the origin of such emission is not determined yet,…