Decreasing density gradients in circumnuclear HII regions of barred galaxies NGC 1022, NGC 1326, and NGC 4314

Citation
J. Franco et al., Decreasing density gradients in circumnuclear HII regions of barred galaxies NGC 1022, NGC 1326, and NGC 4314, ASTROPHYS J, 544(1), 2000, pp. 277-282
Citations number
33
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
544
Issue
1
Year of publication
2000
Part
1
Pages
277 - 282
Database
ISI
SICI code
0004-637X(20001120)544:1<277:DDGICH>2.0.ZU;2-M
Abstract
A reanalysis of the radio continuum emission from circumnuclear regions of the barred galaxies NGC 1022, NGC 1326, and NGC 4314 is presented. The spat ial distributions of Ha and radio continuum are similar and suggest the exi stence of several giant H II regions in the circumnuclear zone. The spectra l indices of the H 11 regions, obtained with similar angular resolution and at three different wavelengths, indicate that in all three galaxies alpha (6)(2) > -0.1. This result suggests the existence of giant H II regions wit h decreasing density gradients. The average density stratifications of thes e H 11 regions could be approximated by power laws of the form n(e) proport ional to r(-omega), with exponents in the range 1.6 < omega < 2.4.