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arXiv · 1906.10759

Star-formation in CALIFA early-type galaxies. A matter of discs

J. Mendez-Abreu·S. F. Sanchez·A. de Lorenzo-Caceres
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Abstract

The star formation main sequence (SFMS) is a tight relation between the galaxy star formation rate (SFR) and its total stellar mass ($M_\star$). Early-type galaxies (ETGs) are often considered as low-SFR outliers of this relation. We study, for the first time, the separated distribution in the SFR vs. $M_\star$ of bulges and discs of 49 ETGs from the CALIFA survey. This is achieved using C2D, a new code to perform spectro-photometric decompositions of integral field spectroscopy datacubes. Our results reflect that: i) star formation always occurs in the disc component and not in bulges; ii) star-forming discs in our ETGs are compatible with the SFMS defined by star forming galaxies at $z \sim 0$; iii) the star formation is not confined to the outskirts of discs, but it is present at all radii (even where the bulge dominates the light); iv) for a given mass, bulges exhibit lower sSFR than discs at all radii; and v) we do not find a deficit of molecular gas in bulges with respect to discs for a given mass in our ETGs. We speculate our results favour a morphological quenching scenario for ETGs.

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J. Mendez-Abreu, S. F. Sanchez, A. de Lorenzo-Caceres. 2019-06-25. Star-formation in CALIFA early-type galaxies. A matter of discs. https://doi.org/10.1093/mnrasl%2Fslz103

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