H II Regions and Diffuse Ionized Gas in 11 Nearby Spiral Galaxies

摘要: We present robust decompositions of the diffuse and discrete components ionized hydrogen in a sample 11 nearby spiral galaxies, spanning wide range star formation rate Hubble type. Traditionally, H II region populations have been interpreted through power-law fits Hα luminosity function (H LF). Here we instead compare measured LF directly with predictions population synthesis models over entire completeness. In our modeling context cluster membership (CMF), defined as number distribution stars per an galaxy, is principal parameter. The CMF was assumed to be truncated power law, excluding stellar clusters initially composed more than 106 (or 103) M > 1 M⊙. conclude that (1) best-fitting slopes vary between -1.75 -2.00, (2) there no evidence for upper limit small 103, (3) initial mass (at 10 M⊙) sparsely populated clusters. Furthermore, functions do not show glitch attributable categorical luminosity-dependent transition density-bounded radiation-bounded regions. This negative result casts doubt on reality "Stromgren luminosity" feature recently reported by Beckman et al. fraction galaxies generally about 0.45 shows perceptible variation type or rate, consistent previous studies. Finally, explored consequences varying physical resolution sensitivity intergalaxy comparisons are most meaningful once these equalized.