Related papers: Helical Fields and Filamentary Molecular Clouds
Context: Filaments are common features in molecular clouds and they play a key role in star formation (SF). Studying their life cycle is essential to fully understand the SF process. Aims: We aim to characterise the impact of magnetic field…
This paper describes 3D simulations of the formation of collapsing cold clumps via thermal instability inside a larger cloud complex. The initial condition was a diffuse atomic, stationary, thermally unstable, 200pc diameter spherical cloud…
We analyze the physical parameters of interstellar filaments that we describe by an idealized model of isothermal self-gravitating infinite cylinder in pressure equilibrium with the ambient medium. Their gravitational state is characterized…
The fragmentation of filaments in molecular clouds has attracted a lot of attention as there seems to be a relation between the evolution of filaments and star formation. The study of the fragmentation process has been motivated by simple…
Cloud-cloud collisions are expected to trigger star formation by compressing gas into dense, gravitationally unstable regions. However, the role of magnetic fields in this process is unclear. We use SPH to model head-on collisions between…
We present a systematic analysis of scale-dependent properties of filamentary structures in seven nearby molecular clouds $-$ Taurus, Ophiuchus, Perseus, Orion A, California, IC 5146, Vela C $-$ using the multiscale extraction method…
Hydrodynamic stability has been a longstanding issue for the cloud model of the broad line region in active galactic nuclei. We argue that the clouds may be gravitationally bound to the supermassive black hole. If true, stabilisation by…
In this paper, we exploit a large suite of {\enzo} cosmological magneto-hydrodynamical simulations adopting uniform mesh resolution, to investigate the properties of cosmic filaments under different baryonic physics and magnetogenesis…
We present observations of the CO isotopologues ($^{12}$CO, $^{13}$CO, and C$^{18}$O) toward the Galactic region with $169\arcdeg.75 \leqslant l \leqslant 174\arcdeg.75$ and $-0\arcdeg.75 \leqslant b \leqslant 0\arcdeg.5$, using the Purple…
We develop models for the self-similar collapse of magnetized isothermal cylinders. We find solutions for the case of a fluid with a constant toroidal flux-to-mass ratio (Gamma_phi=constant) and the case of a fluid with a constant gas to…
The initial conditions of massive star and star cluster formation are expected to be cold, dense and high column density regions of the interstellar medium, which can reveal themselves via near, mid and even far-infrared absorption as…
Two counter-propagating cool and equally dense electron beams are modelled with particle-in-cell (PIC) simulations. The electron beam filamentation instability is examined in one spatial dimension, which is an approximation for a…
A model of magnetic field structure is presented to help test the prevalence of flux freezing in star-forming clouds of various shapes, orientations, and degrees of central concentration, and to estimate their magnetic field strength. The…
Observations show that galaxies and their interstellar media are pervaded by strong magnetic fields with energies in the diffuse component being at least comparable to the thermal and even as large or larger than the turbulent energy. Such…
We discuss the thermal pressures ($n_H T$) in predominantly cold, neutral interstellar gas in the Magellanic Clouds, derived from analyses of the fine-structure excitation of neutral carbon, as seen in high-resolution HST/STIS spectra of…
During the past decade the dynamical importance of magnetic fields in molecular clouds has been increasingly recognized, as observational evidence has accumulated. However, how a magnetic field affect star formation is still unclear.…
Polytropic models are reasonably successful in acounting for the observed features of molecular clouds. Multi-pressure polytropes include the various pressure components that are important in molecular clouds, whereas composite polytropes…
We perform numerical magnetohydrodynamic (MHD) simulations of the gravitational collapse and fragmentation of a cylindrical molecular cloud with the help of the FLASH code. The cloud collapses rapidly along its radius without any signs of…
We study the origin of the non-thermal profiles observed in filamentary structures in galactic molecular clouds by means of numerical dynamical simulations. We find that such profiles are intrinsic features of the end products of…
We investigate the statistical properties of isotropic, stochastic, Gaussian distributed, helical magnetic fields characterized by different shapes of the energy spectra at large length scales and study the associated realizability…