Decreasing Density Gradients in Circumnuclear H ii Regions of Barred Galaxies NGC

A re-analysis of the radio continuum emission from circumnuclear regions of the barred galaxies NGC 1022, 1326 & 4314 is presented. The spatial distributions of Hα and radio continuum are similar and suggest the existence of several giant H ii regions in the circumnuclear zone. The spectral indices of the H ii regions, obtained with similar angular resolution and at three different wavelengths, indicate that in all three galaxies α 6 2 > −0.1. This result suggests the existence of giant H ii regions with decreasing density gradients. The average density stratifications of these H ii regions could be approximated by power-laws of the form n e ∝ r −ω , with exponents in the range 1.6 < ω < 2.4.