Re-analysis of the Radio Luminosity Function of Galactic H II Regions

September 2009 • 2009ApJ...702.1036P

Authors • Paladini, R. • De Zotti, G. • Noriega-Crespo, A. • Carey, S. J.

Abstract • We have re-analyzed continuum and recombination lines radio data available in the literature in order to derive the luminosity function (LF) of Galactic H II regions. The study is performed by considering the first and fourth Galactic quadrants independently. We estimate the completeness level of the sample in the fourth quadrant at 5 Jy, and the one in the first quadrant at 2 Jy. We show that the two samples (fourth or first quadrant) include, as well as giant and supergiant H II regions, a significant number of subgiant sources. The LF is obtained, in each Galactic quadrant, with a generalized Schmidt's estimator using an effective volume derived from the observed spatial distribution of the considered H II regions. The re-analysis also takes advantage of recently published ancillary absorption data allowing to solve the distance ambiguity for several objects. A single power-law fit to the LFs retrieves a slope equal to -2.23 ± 0.07 (fourth quadrant) and to -1.85 ± 0.11 (first quadrant). We also find marginal evidence of a luminosity break at L _knee = 10^23.45 erg s^-1 Hz^-1 for the LF in the fourth quadrant. We convert radio luminosities into equivalent Hα and Lyman continuum luminosities to facilitate comparisons with extragalactic studies. We obtain an average total H II regions Lyman continuum luminosity of 0.89 ± 0.23 × 10⁵³ s^-1, corresponding to 30% of the total ionizing luminosity of the Galaxy.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2009ApJ...702.1036P
• PDF https://iopscience.iop.org/article/10.1088/0004-637X/702/2/1036/pdf
• PDF https://stacks.iop.org/0004-637X/702/1036/pdf
• PREPRINT http://arxiv.org/abs/0907.2216
• ELECTR https://doi.org/10.1088%2F0004-637X%2F702%2F2%2F1036
• SPIRES http://inspirehep.net/search?p=find+eprint+arXiv:0907.2216