Improved method to determine the integrated properties of nuclear rings: NGC 1512

Abstract

The integrated properties of nuclear rings are correlated with their host galaxy's secular evolution and its dynamics, as well as with the formation and evolution of the ring's star cluster population(s). Here we present a new method to accurately measure the spectral energy distribution and current star-formation rate (SFR) of the nuclear ring in the barred spiral galaxy NGC 1512 based on high-resolution {\sl Hubble} and {\sl Spitzer Space Telescope} images. Image degradation does not have a significant negative effect on the robustness of the results. To obtain the ring's SFR for the period spanning $\sim$3--10 Myr, we apply our method to the continuum-subtracted H$\alpha$ and 8 $\mu$m images. The resulting SFR surface density, $\Sigma_{\rm SFR}$=$0.09\, {M}_{\odot} \,{\rm yr}^{-1}$ ${\rm kpc}^{-2}$, which is much higher than the disk-averaged SFR densities in normal galaxies. We also estimate the ring's total stellar mass, log (${M}/{M}_{\odot}$) = 7.1 $\pm$ 0.11 for an average age of $\sim$40 Myr.