Theoretical models of diffuse clouds
نویسندگان
چکیده
منابع مشابه
Extragalactic molecular clouds and chemistry of diffuse interstellar clouds
Zusammenfassung Since the discovery of a cold molecular component of the interstellar medium in the 1970s, it has been realized that most of the dark clouds are actually molecular clouds, consisting mainly of molecular hydrogen and some amount of dust and other molecules. Nowadays, molecular clouds are recognized as places of star-formation in the Milky Way and other galaxies. Therefore, studie...
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Diffuse interstellar clouds have long been thought to be relatively devoid of molecules, because of their low densities and high radiation fields. However, in the past ten years or so, a plethora of polyatomic molecules have been observed in diffuse clouds, via their rotational, vibrational, and electronic transitions. In this review, we propose a new systematic classification method for the di...
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We present a follow-up observation on Geballe and Oka (2010, ApJ, 709, L70), who found high column densities of H+3 100 pc apart from the Galactic center on the lines of sight to 2MASS J17432173 2951430 (J1743) and 2MASS J17470898 2829561 (J1747). The wavelength coverages on these sightlines have been extended in order to observe two key transitions of H+3 — R(3, 3) l and R(2, 2) — which constr...
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1. INTRODUCTION H 3 + is of fundamental importance to interstellar chemistry both because it is a hydrogenic species (and >90% of all nuclei in the universe are hydrogen nuclei; see Figure 1) and because it serves as the universal protonator, initiating a chain of ion-neutral reactions that is responsible for the formation of most interstellar molecules. The chemistry of H 3 + in dense (molecul...
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We observed the 3335 MHz (λ 9cm) F=1-1 line of CH toward a sample of diffuse clouds occulting compact extragalactic mm-wave continuum sources, using the old NRAO 43m telescope. Because radiofrequency observations of CH really must be calibrated with reference to a known CH abundance, we begin by deriving the relationships between CH, E B−V , H 2 and other hydrides found by optical spectroscopy.
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1997
ISSN: 0074-1809
DOI: 10.1017/s0074180900009591