相关论文: The sub-critical illusion: synthetic Zeeman effect…

The mass-to-magnetic flux ratio of molecular clouds is a parameter of central importance as it quantifies the dynamical significance of the magnetic field with respect to gravitational forces. Therefore, it can provide invaluable…

We present the results of a new survey of 23 molecular clouds for the Zeeman effect in OH undertaken with the ATNF Parkes 64-m radio telescope and the NRAO Green Bank 43-m radio telescope. The Zeeman effect was clearly detected in the cloud…

(Edited for length) The Zeeman effect is the only observational technique available to measure directly the strength of magnetic fields in regions of star formation. We review the physics of the Zeeman effect and its practical use in both…

We report here observations of the Zeeman effect in the 18-cm lines of OH in the envelope regions surrounding four molecular cloud cores toward which detections of B(LOS) have been achieved in the same lines, and evaluate the ratio of mass…

Context. Observations of Zeeman split spectral lines represent an important approach to derive the structure and strength of magnetic fields in molecular clouds. In contrast to the uncertainty of the spectral line observation itself, the…

The most accurate measurements of magnetic fields in star-forming gas are based on the Zeeman observations analyzed by Crutcher et al. (2010). We show that their finding that the 3D magnetic field scales approximately as density$^{0.65}$…

Magnetic fields (B-fields) play an important role in molecular cloud fragmentation and star formation, but are very difficult to detect. The temporal correlation between the field strength (B) and gas density (n) of an isolated cloud has…

The ratio of mass and magnetic flux determines the relative importance of magnetic and gravitational forces in the evolution of molecular clouds and their cores. Its measurement is thus central in discriminating between different theories…

Zeeman observations provide the only direct probe of line-of-sight (LOS) magnetic fields in the interstellar medium. To evaluate their accuracy and limitations, we generate synthetic HI Zeeman spectra from magnetohydrodynamic simulations…

We present the results of an extensive Arecibo observational survey of magnetic field strengths in the inter-core regions of molecular clouds to determine their role in the evolution and collapse of molecular clouds as a whole. Sensitive 18…

The Zeeman effect and dust grain alignment are two major methods for probing magnetic fields (B-fields) in molecular clouds, largely motivated by the study of star formation, as the B-field may regulate gravitational contraction and channel…

Until recently, many of the dozens of quantitative predictions of the ambipolar-diffusion theory of gravitational fragmentation (or core formation) of molecular clouds have been confirmed by observations and, just as importantly, no…

We use magnetohydrodynamical simulations of converging flows to investigate the process of molecular cloud formation and evolution out of the magnetised ISM. Here, we investigate whether the observed subcritical HI clouds can become…

Most of our knowledge regarding molecular clouds and the early stages of star formation stems from molecular spectral-line observations. However, the various chemical and radiative-transfer effects, in combination with projection effects,…

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…

The formation of stars is governed by the intricate interplay of nonideal magnetohydrodynamic (MHD) effects, gravity, and turbulence. Computational challenges have hindered a comprehensive 3D exploration of this interplay, posing a…

We introduce a sub-grid model for the non-equilibrium abundance of molecular hydrogen in cosmological simulations of galaxy formation. We improve upon previous work by accounting for the unresolved structure of molecular clouds in a…

We utilize magnetohydrodynamic (MHD) simulations to develop a numerical model for GMC-GMC collisions between nearly magnetically critical clouds. The goal is to determine if, and under what circumstances, cloud collisions can cause…

Magnetic fields play an important role in the evolution of interstellar medium and star formation. As the only direct probe of interstellar field strength, credible Zeeman measurements remain sparse due to the lack of suitable Zeeman…

We present synthetic Hi and CO observations of a simulation of decaying turbulence in the thermally bistable neutral medium. We first present the simulation, with clouds initially consisting of clustered clumps. Self-gravity causes these…