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Related papers: Relative Alignment Between Magnetic Fields and Mol…

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We study how the estimation of the sonic Mach number ($M_s$) from $^{13}$CO linewidths relates to the actual 3D sonic Mach number. For this purpose we analyze MHD simulations which include post-processing to take radiative transfer effects…

The canonical theory of star formation in a magnetized environment predicts the formation of hourglass-shaped magnetic fields during the prestellar collapse phase. In protostellar cores, recent observations reveal complex and strongly…

Solar and Stellar Astrophysics · Physics 2022-09-07 Gianfranco Bino , Shantanu Basu , Masahiro N Machida , Aris Tritsis , Mahmoud Sharkawi , Kundan Kadam , Indrani Das

Dust polarization, which comes from the alignment of aspherical grains to magnetic fields, has been widely employed to study the interstellar medium (ISM) dust properties. The wavelength dependence of the degree of optical polarization,…

Astrophysics of Galaxies · Physics 2024-11-15 Raphael Skalidis

$\textit{Aims.}$ We present a case study to demonstrate the potential of multi-wavelength polarization measurements. The aim is to investigate the effects that dichroic polarization and thermal re-emission have on tracing the magnetic field…

Solar and Stellar Astrophysics · Physics 2015-06-19 S. Reissl , S. Wolf , D. Seifried

We examine several different simplified approaches for modelling the chemistry of CO in three-dimensional numerical simulations of turbulent molecular clouds. We compare the different models both by looking at the behaviour of integrated…

Astrophysics of Galaxies · Physics 2015-05-27 S. C. O. Glover , P. C. Clark

We utilize observations of sub-millimeter rotational transitions of CO from a Herschel Cycle 2 open time program ("COPS", PI: J. Green) to identify previously predicted turbulent dissipation by magnetohydrodynamic (MHD) shocks in molecular…

Astrophysics of Galaxies · Physics 2022-03-17 Rebecca L. Larson , Neal J. Evans , Joel D. Green , Yao-Lun Yang

Determining temperatures in molecular clouds from ratios of CO rotational lines or from ratios of continuum emission in different wavelength bands suffers from reduced temperature sensitivity in the high-temperature limit. In theory, the…

Astrophysics · Physics 2008-11-26 W. F. Wall

The opacity of spiral galaxy disks, from counts of distant galaxies, is compared to HI column densities. The opacity measurements are calibrated using the ``Synthetic Field Method'' from Gonzalez et al (1998) and Holwerda et al. (2005a).…

Astrophysics · Physics 2009-11-11 B. W. Holwerda , R. A. González , Ronald J. Allen , P. C. van der Kruit

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$^{0.65}$…

Astrophysics of Galaxies · Physics 2015-08-06 Pak Shing Li , Christopher F. McKee , Richard I. Klein

Theoretical and observational investigations have indicated that the abundance of carbon monoxide (CO) is very sensitive to intrinsic properties of the gaseous medium, such as density, metallicity, and the background UV field. In order to…

Astrophysics of Galaxies · Physics 2015-05-20 Rahul Shetty , Simon C. Glover , Cornelis P. Dullemond , Ralf S. Klessen

New visible and K-band polarization measurements on stars surrounding molecular clouds in Orion A and stars in the BN vicinity are presented. Our results confirm that magnetic fields located inside the Orion A molecular clouds and in their…

Astrophysics of Galaxies · Physics 2015-05-30 Frédérick Poidevin , Pierre Bastien , Terry J. Jones

We present further observational evidence in support of our earlier proposal (Houde et al. 2000) for detecting the presence of the magnetic field in molecular clouds by comparing spectra of molecular ions with those of neutral molecules.…

We investigate the spectral correlations between different species used to observe molecular clouds. We use hydrodynamic simulations and a full chemical network to study the abundances of over 150 species in typical Milky Way molecular…

Solar and Stellar Astrophysics · Physics 2015-06-23 Brandt A. L. Gaches , Stella S. R. Offner , Erik W. Rosolowsky , Thomas G. Bisbas

Atomic gas in the diffuse interstellar medium (ISM) is organized in filamentary structures. These structures usually host cold and dense molecular clumps. The Galactic magnetic field is considered to play an important role in the formation…

Astrophysics of Galaxies · Physics 2022-09-14 R. Skalidis , K. Tassis , G. V. Panopoulou , J. L. Pineda , Y. Gong , N. Mandarakas , D. Blinov , S. Kiehlmann , J. A. Kypriotakis

Magnetic fields are ubiquitous in the universe and are thought to play an important role in various astrophysical processes. Polarization of thermal dust emission from dust grains aligned with the magnetic field is widely used to measure…

Astrophysics of Galaxies · Physics 2024-02-20 Thiem Hoang , Bao Truong

Recent observations near the Galactic Centre have found several molecular filaments displaying striking helically-wound morphology, which are collectively known as "molecular tornadoes." We investigate the equilibrium structure of these…

Astrophysics of Galaxies · Physics 2017-07-26 Kelvin Au , Jason D. Fiege

Observations of interstellar dust are often used as a proxy for total gas column density $N_\mathrm{H}$. By comparing $\textit{Planck}$ thermal dust data (Release 1.2) and new dust reddening maps from Pan-STARRS 1 and 2MASS (Green et al.…

We report the results of a large-area study of water vapor along the Orion Molecular Cloud ridge, the purpose of which was to determine the depth-dependent distribution of gas-phase water in dense molecular clouds. We find that the water…

In this study, we investigate the shapes of starless and protostellar cores using hydrodynamic, self-gravitating adaptive mesh refinement simulations of turbulent molecular clouds. We simulate observations of these cores in dust emission,…

Astrophysics · Physics 2011-02-11 S. S. R. Offner , M. R. Krumholz

We present a study of the three-dimensional structure of the molecular clouds in the Galactic Centre (GC) using CO emission and OH absorption lines. Two CO isotopologue lines, $^{12}$CO ($J$=1$\rightarrow$0) and $^{13}$CO…