منابع مشابه
Sodium Emission from Io: Implications
The surface of lo may be covered with a layer of ammonia ice containing trace amounts of sodium potassium, and calcium; and atmospheric nitrogen could be formed as a photochemical product of ammonia photolysis. Intense sporadic sodium emission from Io can be excited by collisions involving vib~ationally excited n.itrogen molecules. These metastable molecules may be formed by electron impact, wi...
متن کاملThe Masses of Distant Galaxies from Optical Emission Line Widths
Promising methods for studying galaxy evolution rely on optical emission line width measurements to compare intermediate-redshift objects to galaxies with equivalent masses at the present epoch. However, emission lines can be misleading. We show empirical examples of galaxies with concentrated central star formation from a survey of galaxies in pairs; HI observations of these galaxies indicate ...
متن کاملEMISSION-LINE OBJECTS FROM A PRELIMINARY UKST OBJECTIVE PRISM SURVEY
A visual search has been made of four fields using United Kingdom 1.2m Schmidt Objective Prism plates with a reciprocal dispersion of 1 180 A/mm at HP. Such plate material is ideally suited to searches for emission-line galaxies. We present a catalogue of 53 emission-line objects, which comprises 45 galaxies, where individual HI1 regions are resolved in 16 bright galaxies; 8 are emission li...
متن کاملLine Emission from
We have studied the molecular and ne structure line emission from dense photodissociation regions (PDRs). In particular, we have concentrated on predicting the line emission from CO and H2 molecules. We nd that, when the gas density is su ciently high relative to the FUV ux (n=G0 102 cm 3), self-shielding of the molecules can move the C+/CO and H/H2 atomic-molecular transitions close to the sur...
متن کاملThe UV–Optical Albedo of Broad Emission Line Clouds
We explore the effective UV–optical albedos of a variety of types of broad emission line clouds, as well as their possible effects on the observed spectra of AGN. An important albedo source in moderately ionized ionization-bounded clouds is that due to neutral hydrogen: Rayleigh scattering of continuum photons off the extreme damping wings of Lyα. The photons resulting from this scattering mech...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1974
ISSN: 0074-1809
DOI: 10.1017/s0074180900025766