NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-06-26 T14:58:40 PDT
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For refcode 2013ApJ...772...27L:
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2013ApJ...772...27L The Paalpha Luminosity Function of H II Regions in Nearby Galaxies from HST/NICMOS Liu, Guilin; Calzetti, Daniela; Kennicutt, Robert C., Jr.; Schinnerer, Eva; Sofue, Yoshiaki; Komugi, Shinya; Egusa, Fumi; Scoville, Nicholas Z. Abstract. The H II region luminosity function (LF) is an important tool for deriving the birthrates and mass distribution of OB associations and is an excellent tracer of the newly formed massive stars and associations. To date, extensive work (predominantly in Halpha) has been done from the ground, which is hindered by dust extinction and the severe blending of adjacent (spatially or in projection) H II regions. Reliably measuring the properties of H II regions requires a linear resolution <40 pc, but analyses satisfying this requirement have been done only in a handful of galaxies, so far. As the first space-based work using a galaxy sample, we have selected 12 galaxies from our HST/NICMOS Paalpha survey and studied the LF and size distribution of H II regions both in individual galaxies and cumulatively, using a virtually extinction-free tracer of the ionizing photon rate. The high angular resolution and low sensitivity to diffuse emission of NICMOS also offer an advantage over ground-based imaging by enabling a higher degree of de-blending of the H II regions. We do not confirm the broken power-law LFs found in ground-based studies. Instead, we find that the LFs, both individual and co-added, follow a single power law dN(L)/dln LvpropL ^--1^, are consistent with the mass function of star clusters in nearby galaxies, and are in agreement with the results of the existing analyses with Hubble Space Telescope (HST) data. The individual and co-added size distributions of H II regions are both roughly consistent with dN(D)/dln DvpropD ^--3^, but the power-law scaling is probably contaminated by blended regions or complexes. Based on observations taken with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555. These observations are associated with program GO-11080. Key words: galaxies: individual, H II regions
Retrieve 12 NED objects in this reference.
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