Properties of H II region populations in galaxies. 2. The H II region luminosity function
Feb, 1989
21 pages
Published in:
- Astrophys.J. 337 (1989) 761-781
DOI:
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Abstract: (ADS)
H-alpha emission-line fluxes have been measured for all of the detected H II regions in 30 nearby spiral and irregular galaxies, and these data are used to study the behavior of the H II region luminosity functions (LFs). In most galaxies, the LF is well represented by a power law function. Both the normalization and the shape of the LF change systematically with Hubble type. Early-type spirals possess fewer H II regions of all luminosities, a steeper LF, and in many cases an upper cutoff or turnover in the LF. Taken together, these effects account for the virtual absence of 'supergiant' H II regions such as 30 Doradus in Sa-Sb galaxies. Most of the massive stars in late-type spiral and irregular galaxies form in large H II/OB complexes, while in early-type spirals the bulk of the massive star formation occurs in small regions ionized by no more than a few OB stars.Associated ArticlesPart 1 Part 2 References(0)
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