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Related papers: Angular Momentum in Giant Molecular Clouds. I. The…

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Using the PMO-13.7m millimeter telescope at Delingha in China, we have conducted a large-scale simultaneous survey of $^{12}$CO, $^{13}$CO, and C$^{18}$O J=1-0 emission toward the Rosette molecular cloud (RMC) region with a sky coverage of…

Astrophysics of Galaxies · Physics 2018-10-10 Chong Li , Hongchi Wang , Miaomiao Zhang , Yuehui Ma , Min Fang , Ji Yang

Kinematic distances to 750 molecular clouds identified in the 13CO J=1-0 Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey (BU-FCRAO GRS) are derived assuming the Clemens rotation curve of the Galaxy. The…

Astrophysics of Galaxies · Physics 2009-07-22 Julia Roman-Duval , James M. Jackson , Mark Heyer , Alexis Johnson , Jill Rathborne , Ronak Shah , Robert Simon

We present the high angular resolution and high sensitivity images of the "Circum-Nuclear Disk (CND)" and its surrounding region of Milky Way Galaxy in the CS J=2-1, SiO v=0 J=2-1, H^13CO^+ J=1-0, C^34S J=2-1, and CH_3OH J_{K_a,…

Aims: we studied the global distribution and kinematics of the extra-planar neutral gas in the Milky Way. Methods: we built 3D models for a series of Galactic HI layers, projected them for an inside view, and compared them with the…

Astrophysics of Galaxies · Physics 2015-05-20 Antonino Marasco , Filippo Fraternali

(Abridged) Massive stars can determine the evolution of molecular clouds with their strong ultraviolet (UV) radiation fields. Moreover, UV radiation is relevant in setting the thermal gas pressure in star-forming clouds, whose influence can…

The atomic phase of the interstellar medium plays a key role in the formation process of molecular clouds. Due to the line-of-sight confusion in the Galactic plane that is associated with its ubiquity, atomic hydrogen emission has been…

Molecular hydrogen clouds are a key component of the interstellar medium because they are the birthplaces for stars. They are embedded in atomic gas that pervades the interstellar space. However, the details of how molecular clouds assemble…

We use atomic hydrogen (HI) data from the Southern Galactic Plane Survey to study the kinematics of the fourth quadrant of the Milky Way. By measuring the terminal velocity as a function of longitude throughout the fourth Galactic quadrant…

Astrophysics · Physics 2009-11-13 N. M. McClure-Griffiths , John M. Dickey

We have used the ATCA and the SEST to map the large-scale atomic and molecular gas in the nearby Circinus galaxy. The HI mosaic of Circinus exhibits the warps in position angle and inclination revealed in the single-pointing image, both of…

Astrophysics · Physics 2009-11-13 S. J. Curran , B. S. Koribalski , I. Bains

We performed sub-parsec (~0.06pc) scale simulations of two idealised molecular clouds with different masses undergoing a collision. Gas clumps with density greater than 1e-20 g/cm3 (0.3e4 cm-3) were identified as pre-stellar cores and…

Astrophysics of Galaxies · Physics 2015-06-22 Ken Takahira , Elizabeth J. Tasker , Asao Habe

The formation of molecular clouds out of HI gas is the first step toward star formation. Its metallicity dependence plays a key role to determine star formation through the cosmic history. Previous theoretical studies with detailed chemical…

Astrophysics of Galaxies · Physics 2023-08-29 Masato I. N. Kobayashi , Kazunari Iwasaki , Kengo Tomida , Tsuyoshi Inoue , Kazuyuki Omukai , Kazuki Tokuda

Molecular clouds (MC) are the densest and coldest component of the interstellar gas, and the sites of star formation. They are also turbulent and fractal and their masses and sizes span several orders of magnitude. It is also generally…

Astrophysics · Physics 2009-11-07 Javier Ballesteros-Paredes

The physical conditions of the Galactic center (GC) clouds moving with non-circular velocities are not well-known. We have studied the physical conditions of these clouds with the aim of better understanding the origin of the outstanding…

High-velocity clouds (HVC), fast-moving ionized and neutral gas clouds found at high galactic latitudes, may play an important role in the evolution of the Milky Way. The extent of this role depends sensitively on their distances and total…

Astrophysics of Galaxies · Physics 2015-06-04 N. Lehner , J. C. Howk , C. Thom , A. J. Fox , J. Tumlinson , T. M. Tripp , J. D. Meiring

Cold atomic hydrogen clouds are the precursors of molecular clouds. Due to self-absorption, the opacity of cold atomic hydrogen may be high, and this gas may constitute an important mass component of the interstellar medium (ISM). Atomic…

Astrophysics of Galaxies · Physics 2020-01-08 Boyang Liu , Di Li , Lister Staveley-Smith , Lei Qian , Tony Wong , Paul Goldsmith

Observational evidence from local star-forming regions mandates that star formation occurs shortly after, or even during, molecular cloud formation. Models of the formation of molecular clouds in large-scale converging flows have identified…

Astrophysics of Galaxies · Physics 2015-05-27 Jonathan Carroll-Nellenback , Adam Frank , Fabian Heitsch

A set of diffuse interstellar clouds in the inner Galaxy within a few hundred pc of the Galactic plane has been observed at an angular resolution of ~1 arcmin combining data from the NRAO Green Bank Telescope and the Very Large Array. At…

Astrophysics of Galaxies · Physics 2015-06-15 Yurii Pidopryhora , Felix J. Lockman , John M. Dickey , Michael P. Rupen

We present a catalogue of 453 molecular clouds in M31 extracted from CO J=1-0 data observed with CARMA using a dendrogram. Our clouds have the mean values of 2.8 km s$^{-1}$, 22.1 pc and 10$^{5.2}$ M$_\odot$ for the velocity dispersion,…

Astrophysics of Galaxies · Physics 2025-12-30 J. Armijos-Abendaño , S. A. Eales , M. W. L. Smith

Giant molecular clouds (GMCs) are the primary reservoirs of cold, star-forming molecular gas in the Milky Way and similar galaxies, and thus any understanding of star formation must encompass a model for GMC formation, evolution, and…

Probing magnetic fields in Giant Molecular Clouds is often challenging. Fortunately, recently simulations show that analysis of velocity gradients (the Velocity Gradient Technique) can be used to map out the magnetic field morphology of…

Astrophysics of Galaxies · Physics 2019-11-06 Yue Hu , Ka Ho Yuen , A. Lazarian , Laura M. Fissel , P. A. Jones , M. R. Cunningham