منابع مشابه
Radiation Hydrodynamical Evolution of Primordial H Ii Regions
We simulate the ionization environment of z ∼ 20 luminous objects formed within the framework of the current CDM cosmology and compute their UV escape fraction. These objects are likely single very massive stars that are copious UV emitters. We present analytical estimates as well as one–dimensional radiation hydrodynamical calculations of the evolution of these first HII regions in the univers...
متن کاملUltracompact H Ii Regions
RESUMEN Discutimos algunos resultados observacionales recientes sobre regiones H II ultracompactas. En particular, discutimos la emisión extendida de algunas regiones H II UC y el descubrimiento de una nueva clase, denominada regiones H II " hipercompactas ". Además, describimos la obtención de la estructura de densidad usando la técnica del análisis deí ındice espectral. ABSTRACT We discuss so...
متن کاملThere’s Life in H Ii Regions Yet!
We give an overview of the literature on ionization front structure and propagation and comment on recombination front structures. We discuss the formation of cometary tails by photoionization of globules and note the importance of including the diffuse component of the ionizing radiation field. We finally briefly comment on the formation of small scale structures in H II regions.
متن کاملA new scheme of radiation transfer in H II regions including transient heating of grains
A new scheme of radiation transfer for understanding infrared spectra of H II regions, has been developed. This scheme considers non-equilibrium processes (e.g. transient heating of the very small grains, VSG; and the polycyclic aromatic hydrocarbon, PAH) also, in addition to the equilibrium thermal emission from normal dust grains (BG). The spherically symmetric interstellar dust cloud is segm...
متن کاملDiscovery of Intergalactic H ii Regions
We have discovered a number of very small isolated H ii regions 20-30 kpc from their nearest galaxy. The H ii regions appear as tiny emission line dots (ELdots) in narrow band images obtained by the NOAO Survey for Ionization in Neutral Gas Galaxies (SINGG). We have spectroscopic confirmation of 5 isolated H ii regions in 3 systems. The Hα luminosities of the H ii regions are equivalent to the ...
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ژورنال
عنوان ژورنال: The Astronomical Journal
سال: 1966
ISSN: 0004-6256
DOI: 10.1086/109890