Results 41 to 50 of about 14,604 (166)

Variation in X_CO Factor in N55 Region

Universe
The XCO factor is defined as XCO=N(H2)/W12CO. It is useful for estimating cloud mass. However, there is only limited research on how the XCO factor varies within a single cloud.
Qiang Li, Mingyue Li, Li Zhang, Songpeng Pei   +3 more
doaj   +1 more source

On the Spatial Distribution of 13CO Structures within 12CO Molecular Clouds

The Astrophysical Journal, 2023
We look into the 2851 ^12 CO molecular clouds harboring ^13 CO structures to reveal the distribution of the projected angular separations and radial velocity separations between their internal ^13 CO structures.
Lixia Yuan, Ji Yang, Fujun Du, Xunchuan Liu, Yang Su, Qing-Zeng Yan, Xuepeng Chen, Yan Sun, Shaobo Zhang, Xin Zhou, Yuehui Ma   +10 more
doaj   +1 more source

The approach to collapse of molecular clouds [PDF]

Monthly Notices of the Royal Astronomical Society, 2009
The dense molecular cloud cores that form stars, like other self-gravitating objects, undergo bulk oscillations. Just at the point of gravitational instability, their fundamental oscillation mode has zero frequency. We study, using perturbation theory, the evolution of a spherical cloud that possesses such a frozen mode.
Stahler, Steven W., Yen, Jeffrey J.
openaire   +2 more sources

RETHINKING A MYSTERIOUS MOLECULAR CLOUD [PDF]

The Astrophysical Journal, 2015
Accepted for publication in ApJ. 16 pages, 13 figures.
openaire   +2 more sources

Outer-Galaxy molecular clouds [PDF]

Symposium - International Astronomical Union, 1985
Since our original report of CO emission from outside the solar circle in the first quadrant (Kutner and Mead, 1981) we have extended the observations in two ways: (1) We have improved latitude and longitude coverage. Preliminary results on the latitude distribution were reported by Kutner (1983).
Marc L. Kutner, Kathryn N. Mead
openaire   +1 more source

The Nature of Shocks in Molecular Clouds [PDF]

International Astronomical Union Colloquium, 1989
AbstractEvidence is presented to suggest that the shocked molecular hydrogen emission in the brightest part of the Orion outflow is produced in a J-shock and not a C-shock; that this is true throughout the entire flow; that it may be true in many outflow sources; and that this exacerbates problems with current explanations of the very wide velocity ...
openaire   +1 more source

Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores

Open Astronomy, 2011
Although hydrogen cyanide has become quite a common molecular tracing species for a variety of astrophysical sources, it, however, exhibits dramatic non-LTE behaviour in its hyperfine line structure.
Loughnane R. M., Redman M. P., Keto E. R., Lo N., Cunningham M. R.   +4 more
doaj   +1 more source

PHANGS-JWST: The largest extragalactic molecular cloud catalog traced by polycyclic aromatic hydrocarbon emission

Astronomy & Astrophysics
High-resolution JWST images of nearby spiral galaxies reveal polycyclic aromatic hydrocarbon (PAH) structures that potentially trace molecular clouds, even CO-dark regions.
Bazzi Z., Colombo D., Bigiel F., Leroy A. K., Rosolowsky E., Sandstrom K., Duarte-Cabral A., Faustino Vieira H., Kobayashi M. I. N., He H., Meidt S. E., Barnes A. T., Klessen R. S., Glover S. C. O., Thorp M. D., Pan H.-A., Chown R., Smith R. J., Dale D. A., Williams T. G., Amiri A., Dlamini S., Chastenet J., Sarbadhicary S. K., Hughes A., Lee J. C., Hands L.   +26 more
doaj   +1 more source

Molecular Clouds and Star Formation Rate in Disk Galaxies

Open Astronomy, 2016
We use N-body/hydrodynamic simulations of a Milky Way-like galaxy to study the physical properties of giant molecular clouds and star formation rate on different spatial scales.
Vasiliev E. O., Khoperskov S. A., Khoperskov A. V.   +2 more
doaj   +1 more source

Molecular Clouds at High Z [PDF]

Symposium - International Astronomical Union, 1991
The evidence for the existence of molecular clouds at large distances from the Galactic plane is reviewed. The molecular clouds at high Galactic latitudes are shown to be largely confined to the Galactic plane. There is evidence for one giant molecular cloud as much as four scale heights from the Galactic plane, but given the sample size from which the
openaire   +1 more source