Contribution of the disks to the SFR in the local Universe using Integral Field Spectroscopy from CALIFA

TL;DR

This study uses CALIFA integral field spectroscopy data to analyze the spatial distribution of star formation in nearby galaxies, finding that disks contribute approximately 88% to the total star formation rate in the local universe.

Contribution

It provides a detailed validation of Hα as a tracer for SFR and quantifies the disk contribution to galaxy star formation using spatially-resolved data.

Findings

Hα luminosity is a reliable SFR indicator in the local universe.

Disks contribute about 88% to the total SFR in nearby galaxies.

Validated methods for future high-redshift studies.

Abstract

The Calar Alto Legacy Integral Field Area survey (CALIFA survey) is providing Integral Field Spectroscopy (IFS) data in the entire optical window for a diameter-limited sample of 600 objects in the Local Universe (0.005$<$z$<$0.03). One of the main goals of this survey is to explore the spatial distribution of the star formation in nearby galaxies free from the limitations associated to either UV (dust attenuation) or narrow-band H$\alpha$ imaging (underlying H$\beta$ absorption). These are limitations that have prevented (until now) carrying out a detailed study of the evolution of the SFR by components (nuclei, bulges, disks), even locally. This kind of studies are key, for example, for understanding how galaxies really evolve from the Blue Cloud to the Red Sequence. We will first discuss in detail the validity of the assumption that the SFR given by the extincion-corrected H$\alpha$ is a good measure of the total SFR by means of cross-comparing this with other SFR estimators, namely the integrated UV+22$\mu$m, UV+TIR, H$\alpha_{\rm{obs}}$+22$\mu$m, or H$\alpha_{\rm{obs}}$+TIR. Only once these effects are properly accounted for we can obtain preliminary results from the spatially-resolved analysis of the contribution of disks to the total SFR in the Local Universe, as a local benchmark for future studies of disks at high redshift. Our analysis shows that at least in the Local Universe the H$\alpha$ luminosity derived from observations of the CALIFA IFS survey can be used to trace the SFR and that the disk to total (disk + bulge) SFR ratio is on average $\sim$88 $\%$.