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Related papers: Centroid Velocity Statistics of Molecular Clouds

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We compare the statistical properties of J=1-0 13CO spectra observed in the Perseus Molecular Cloud with synthetic J=1-0 13CO spectra from a 5 pc model cloud. The synthetic spectra are computed solving the non-LTE radiative transfer problem…

Astrophysics · Physics 2007-05-23 Paolo Padoan , John Bally , Youssef Billawala , Mika Juvela , AAke Nordlund

Context. Tighter constraints on metal-poor stars we observe are needed to better understand the chemical processes of the early Universe. Computing a stellar spectrum in 3D allows one to model complex stellar behaviours, which cannot be…

Solar and Stellar Astrophysics · Physics 2017-02-22 A. J. Gallagher , E. Caffau , P. Bonifacio , H. -G. Ludwig , M. Steffen , D. Homeier , B. Plez

We apply gravity-based and density-based methods to identify clouds in numerical simulations of the star-forming, three-phase interstellar medium (ISM), and compare their properties and their global correlation with the star formation rate…

Astrophysics of Galaxies · Physics 2020-07-29 S. Alwin Mao , Eve C. Ostriker , Chang-Goo Kim

The Fourier power spectrum is one of the most widely used statistical tools to analyze the nature of magnetohydrodynamic turbulence in the interstellar medium. Lazarian & Pogosyan (2004) predicted that the spectral slope should saturate to…

Astrophysics of Galaxies · Physics 2015-06-15 Blakesley Burkhart , A. Lazarian , V. Ossenkopf , J. Stutzki

The $^{13}$CO molecule is often used as a column density tracer in regions where the $^{12}$CO emission saturates. The $^{13}$CO column density is then related to that of $^{12}$CO by a uniform isotopic ratio. A similar approximation is…

Astrophysics of Galaxies · Physics 2016-04-25 László Szűcs , Simon C. O. Glover , Ralf S. Klessen

We use ALMA and IRAM 30-m telescope data to investigate the relationship between the spectroscopically-traced dense gas fraction and the cloud-scale (120 pc) molecular gas surface density in five nearby, star-forming galaxies. We estimate…

A computational fluid dynamics (CFD) model that solves the steady-state Reynolds-Averaged Navier-Stokes (RANS) equations for buoyant compressible pollution dispersion under different meteorological conditions is developed. A 6.4 km by 6.4…

Fluid Dynamics · Physics 2022-11-15 Zhihao Li , Rebecca Tanzer-Gruener , Albert Presto , Peter Adams , Satbir Singh

We used adaptive mesh refinement hydrodynamic cosmological simulations of a $z=1$ Milky Way-type galaxy and a $z=0$ Dwarf galaxy and generated synthetic quasar absorption-line spectra of their circumgalactic medium (CGM). Our goal is to…

We compare simulations, including the Illustris simulations, to observations of CIV and CII absorption at z=2-4. These are the CIV column density distribution function in the column density range $10^{12} - 10^{15}$ cm$^{-2}$, the CIV…

Astrophysics of Galaxies · Physics 2016-09-07 Simeon Bird , Kate H. R. Rubin , Joshua Suresh , Lars Hernquist

A physical model and two-dimensional numerical method for computing the evolution and spectra of protostellar clouds are described. The physical model is based on a system of magneto-gasdynamical equations, including ohmic and ambipolar…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 A. G. Zhilkin , Ya. N. Pavlyuchenkov , S. N. Zamozdra

Using 3D hydrodynamic calculations we simulate formation of molecular clouds in the Galaxy. The simulations take into account molecular hydrogen chemical kinetics, cooling and heating processes. Comprehensive gravitational potential…

Astrophysics of Galaxies · Physics 2015-06-05 S. A. Khoperskov , E. O. Vasiliev , A. M. Sobolev , A. V. Khoperskov

We report the results of a 100 square degree survey of the Taurus Molecular Cloud region in the J = 1-0 transition of 12CO and 13CO. The image of the cloud in each velocity channel includes ~ 3 million Nyquist sampled pixels on a 20" grid.…

Astrophysics · Physics 2009-12-08 Paul F. Goldsmith , Mark Heyer , Gopal Narayanan , Ronald Snell , Di Li , Chris Brunt

It is believed that turbulence may have a significant impact on star formation and the dynamics and evolution of the molecular clouds in which this occurs. It is also known that non-ideal magnetohydrodynamic effects influence the nature of…

Astrophysics of Galaxies · Physics 2015-06-05 T. P. Downes

We use 3D numerical MHD simulations to follow the evolution of cold, turbulent, gaseous systems with parameters representing GMC conditions. We study three cloud simulations with varying mean magnetic fields, but identical initial velocity…

Astrophysics · Physics 2008-11-26 Eve C. Ostriker , James M. Stone , Charles F. Gammie

Understanding the microscopic mechanism of chemical vapor deposition (CVD) growth of two-dimensional molybdenum disulfide (2D MoS2) is a fundamental issue towards the function-oriented controlled growth. In this work, we report results on…

Materials Science · Physics 2017-04-21 Dancheng Zhu , Haibo Shu , Feng Jiang , Danhui Lv , Vijay Asokan , Omar Omar , Jun Yuan , Ze Zhang , Chuanhong Jin

We present Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope observations of high, intermediate, and low ion absorption in high-velocity cloud Complex C along the lines of sight toward five active galaxies. Our purpose is to…

We use Keck HIRES spectra of three intermediate redshift QSOs to study the physical state and kinematics of the individual components of CIV selected heavy element absorption systems. Fewer than 8 % of all CIV lines with column densities…

Astrophysics · Physics 2009-10-28 M. Rauch , W. L. W. Sargent , D. S. Womble , T. A. Barlow

UV absorption studies with FUSE have observed H2 molecular gas in translucent and diffuse clouds. Observations of the 158 micron [C II] fine structure line with Herschel also trace the same H2 molecular gas in emission. We present [C II]…

Astrophysics of Galaxies · Physics 2017-04-12 Thangasamy Velusamy , William Langer , Paul Goldsmith , Jorge L. Pineda

We used HIRES/Keck profiles (R=6 km/s) of MgII and FeII in combination with FOS/HST spectra (R=230 km/s) to place constraints on the physical conditions (metallicities, ionization conditions, and multi-phase distribution) of absorbing gas…

Astrophysics · Physics 2009-10-30 Christopher W. Churchill , Jane C. Charlton
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