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

Paladini, R. and DeZotti, G. and Noriega-Crespo, A. and Carey, S. J. (2009) Re-analysis of the Radio Luminosity Function of Galactic H II Regions. Astrophysical Journal, 702 (2). pp. 1036-1047. ISSN 0004-637X.

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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 × 10^(53) s^(–1), corresponding to 30% of the total ionizing luminosity of the Galaxy.

Item Type:Article
Related URLs:
URLURL TypeDescription
Paladini, R.0000-0002-5158-243X
DeZotti, G.0000-0003-2868-2595
Carey, S. J.0000-0002-0221-6871
Additional Information:© 2009 American Astronomical Society. Print publication: Issue 2 (2009 September 10); received 2008 July 1; accepted for publication 2009 July 14; published 2009 August 18.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Agenzia Spaziale Italiana (ASI)I/016/07/0 “COFIS”
Subject Keywords:Galaxy: general; H II regions; radio continuum: stars; stars: luminosity function, mass function
Issue or Number:2
Record Number:CaltechAUTHORS:20090917-123207415
Persistent URL:
Official Citation:Re-analysis of the Radio Luminosity Function of Galactic H II Regions R. Paladini, G. DeZotti, A. Noriega-Crespo, and S. J. Carey 2009 ApJ 702 1036-1047 doi: 10.1088/0004-637X/702/2/1036
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15912
Deposited By: Jason Perez
Deposited On:21 Sep 2009 23:11
Last Modified:03 Oct 2019 01:05

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