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相关论文: Turbulence in Zeeman Measurements from Molecular C…

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We perform ideal MHD high resolution AMR simulations with driven turbulence and self-gravity and find that long filamentary molecular clouds are formed at the converging locations of large-scale turbulence flows and the filaments are…

星系天体物理 · 物理学 2019-04-10 Pak Shing Li , Richard I. Klein

A fundamental property of molecular clouds is that they are turbulent, but how this turbulence is generated and maintained is unknown. One possibility is that stars forming within the cloud regenerate turbulence via their outflows, winds…

太阳与恒星天体物理 · 物理学 2018-10-17 Stella S. R. Offner , Yue Liu

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$^{0.65}$…

星系天体物理 · 物理学 2015-08-06 Pak Shing Li , Christopher F. McKee , Richard I. Klein

[abridged] We determine the relationship between turbulence energy and gas density variance for 15 molecular clouds in the Solar neighbourhood. We use the linewidths of the CO molecule as the probe of the turbulence energy (sonic Mach…

星系天体物理 · 物理学 2017-12-06 Jouni Kainulainen , Christoph Federrath

We examine how well the physical properties of clumps in turbulent molecular clouds can be determined by measurements of observed clump structures. We compare simulated observations of three-dimensional numerical models of isothermal,…

天体物理学 · 物理学 2009-11-07 Javier Ballesteros-Paredes , Mordecai-M. Mac Low

How important is the magnetic (B-) field when compared to gravity and turbulence in the star-formation process? Does its importance depend on scale and location? We summarize submm dust polarization observations towards the large…

The strengths of magnetic fields in interstellar gas clouds are obtained through observations of the circular polarization of spectral line radiation. Irregularities in this magnetic field may be present due to turbulence, waves or perhaps…

天体物理学 · 物理学 2009-10-31 W. D. Watson , D. S. Wiebe , R. M. Crutcher

Magnetic fields of molecular clouds in the Central Molecular Zone (CMZ) have been relatively underobserved at sub-parsec resolution. Here we report JCMT/POL2 observations of polarized dust emission in the CMZ, which reveal magnetic field…

One of the key problems in star formation research is to determine the role of magnetic fields. Starting from the atomic inter-cloud medium (ICM) which has density nH ~ 1 per cubic cm, gas must accumulate from a volume several hundred pc…

星系天体物理 · 物理学 2015-05-13 Hua-bai Li , C. Darren Dowell , Alyssa Goodman , Roger Hildebrand , Giles Novak

Magnetic fields are an important component of the interstellar medium (ISM) of galaxies. The thermal gas in the ISM has a multiphase structure, broadly divided into ionised, atomic, and molecular phases. The connection between the…

星系天体物理 · 物理学 2025-04-01 Amit Seta , N. M. McClure-Griffiths

The magnetic field strength to gas density relation in the interstellar medium is of fundamental importance. We present and compare Bayesian analyses of the B-n relation for two comprehensive observational data sets: a Zeeman data set and…

We discuss the nature of the velocity dispersion vs. size relation for molecular clouds. In particular, we add to previous observational results showing that the velocity dispersions in molecular clouds and cores are not purely functions of…

Mass-to-flux ratios measured via the Zeeman effect suggest the existence of a transition from a magnetically sub-critical state in HI clouds to a super-critical state in molecular clouds. However, due to projection, chemical, and excitation…

星系天体物理 · 物理学 2024-09-27 Zipeng Hu , Benjamin D. Wibking , Mark R. Krumholz

The molecular component of the Galaxy is comprised of turbulent, magnetized clouds, many of which are self-gravitating and form stars. To understand how these clouds' evolution may depend on their level of turbulence, mean magnetization,…

天体物理学 · 物理学 2009-10-31 Eve C. Ostriker , Charles F. Gammie , James M. Stone

We demonstrate that the combination of Zeeman, polarimetry and ion-to-neutral molecular line width ratio measurements permits the determination of the magnitude and orientation of the magnetic field in the weakly ionized parts of molecular…

We study the magnetic field to density ($B-\rho$) relation in turbulent molecular clouds with dynamically important magnetic fields using nonideal three-dimensional magnetohydrodynamic simulations. Our simulations show that there is a…

星系天体物理 · 物理学 2022-03-30 Sayantan Auddy , Shantanu Basu , Takahiro Kudoh

We summarize recent numerical results on the control of the star formation efficiency (SFE), addressing the effects of turbulence and the magnetic field strength. In closed-box numerical simulations, the effect of the turbulent Mach number…

天体物理学 · 物理学 2009-11-11 Enrique Vazquez-Semadeni

We present a set of numerical experiments designed to systematically investigate how turbulence and magnetic fields influence the morphology, energetics, and dynamics of filaments produced in wind-cloud interactions. We cover 3D…

星系天体物理 · 物理学 2017-12-06 Wladimir Banda-Barragán , Christoph Federrath , Roland Crocker , Geoffrey Bicknell

We (Li et al. 2009; Paper-I) compared the magnetic field directions inferred from polarimetry data obtained from 100-pc scale inter-cloud media (ICM) and from sub-pc scale molecular cloud cores. The highly correlated result led us to…

星系天体物理 · 物理学 2019-08-10 Y. Zhang , Z. Guo , H. H. Wang , H-b Li

We study the linear evolution of small perturbations in self-gravitating fluid systems with magnetic fields. We consider wave-like perturbations to nonuniform filamentary and sheet-like hydrostatic equilibria in the presence of a uniform…

天体物理学 · 物理学 2015-06-24 Curtis S. Gehman , Fred C. Adams , Richard Watkins