Results 21 to 30 of about 42,575 (298)
Evidence for a Molecular Cloud Origin for Gamma-Ray Bursts: Implications for the Nature of Star Formation in the Universe [PDF]
, 2001 It appears that the majority of rapidly-, well-localized gamma-ray bursts with undetected, or dark, optical afterglows, or `dark bursts' for short, occur in clouds of size R > 10L_{49}^{1/2} pc and mass M > 3x10^5L_{49} M_{sun}, where L is the isotropic ...
Dal Fiume D. +7 more
core +2 more sources
Molecular Formation in Hot Diffuse Clouds [PDF]
Symposium - International Astronomical Union, 1980 A description is given of the processes of molecular formation and destruction in diffuse interstellar clouds and detailed models of the clouds lying towards ζ Ophiuchi, ζ Persei and o Persei are used to assess the validity of gas phase chemistry. Modifications that may arise from shock-heated regions are discussed.
openaire +1 more source
Origin of CH+ in diffuse molecular clouds [PDF]
Astronomy & Astrophysics, 2017 Context. Molecular clouds are known to be magnetised and to display a turbulent and complex structure where warm and cold phases are interwoven. The turbulent motions within molecular clouds transport molecules, and the presence of magnetic fields induces a relative velocity between neutrals and ions known as the ion-neutral drift (vd).
Valdivia, Valeska +5 more
openaire +2 more sources
Two populations of diffuse molecular clouds
The Astrophysical Journal, 1988 Sensitive CO and (C-13)O measurements have been made toward a number of diffuse clouds and high-latitude molecular clouds (HLCs). The results suggest that the diffuse clouds are an inhomogeneous class of objects which can be separated according to their CO column density.
Elizabeth A. Lada, Leo Blitz
openaire +1 more source
Diffusive versus Free-streaming Cosmic-Ray Transport in Molecular Clouds [PDF]
The Astrophysical Journal, 2019 Abstract Understanding the cosmic-ray (CR) ionization rate is crucial in order to simulate the dynamics of molecular clouds, and interpret the chemical species observed in these objects. Calculating the CR ionization rate requires both accurate knowledge of the spectrum of MeV to GeV protons at the edge of the cloud as well as a model ...
Kedron Silsbee, Alexei V. Ivlev
openaire +3 more sources
The Transition from Diffuse Molecular Gas to Molecular Cloud Material in Taurus [PDF]
The Astrophysical Journal, 2021 Abstract We study four lines of sight that probe the transition from diffuse molecular gas to molecular cloud material in Taurus. Measurements of atomic and molecular absorption are used to infer the distribution of species and the physical conditions toward stars behind the Taurus Molecular Cloud (TMC).
S. R. Federman +8 more
openaire +3 more sources
[CII] observations of H$_2$ molecular layers in transition clouds [PDF]
, 2010 We present the first results on the diffuse transition clouds observed in [CII] line emission at 158 microns (1.9 THz) towards Galactic longitudes near 340deg (5 LOSs) and 20deg (11 LOSs) as part of the GOT C+ survey.
Abdo +31 more
core +1 more source
CH observations of diffuse molecular clouds
The Astrophysical Journal, 1989 A survey of CH 3.3 GHz emission from a sample of high-latitude molecular clouds, diffuse clouds, and heavily reddened globular clusters is presented. The F = 1-1 main-line transition was detected in every molecular cloud in the sample and in two out of four globular cluster lines of sight. The high rate of detections in the low-extinction high-latitude
Loris Magnani +3 more
openaire +1 more source
Magnetic Fields in Diffuse HI and Molecular Clouds [PDF]
, 2005 50 pages, 14 figures, to be published as book chapter in 'Cosmic Magnetic Fields'
Heiles, Carl, Crutcher, Richard
openaire +2 more sources
Diffuse molecular clouds at high galactic latitude [PDF]
Symposium - International Astronomical Union, 1991 The IRAS 60 and 100 μm flux from cirrus clouds are commonly explained by dust continuum emission. But this explanation in some cases requires unexpectedly high dust temperatures.We argue that the contribution of fine structure emission of neutral oxygen, O°(63 μm), can be significant in the IRAS 60 μm band. The 0°(63 μm) line emission together with the
openaire +1 more source