Star Formation in the Local Universe from the CALIFA Sample. II. Activation and Quenching Mechanisms in Bulges, Bars, and Disks

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We estimate the current extinction-corrected Ha star formation rate (SFR) of the different morphological components that shape galaxies (bulges, bars, and disks). We use a multicomponent photometric decomposition based on Sloan Digital Sky Survey imaging to Calar Alto Legacy Integral Field Area Integral Field Spectroscopy (IFS) datacubes for a sample of 219 galaxies. This analysis reveals an enhancement of the central SFR and specific SFR (sSFR = SFR/M-star) in barred galaxies. Along the main sequence, we find that more massive galaxies in total have undergone efficient suppression (quenching) of their star formation, in agreement with many studies. We discover that more massive disks have had their star formation quenched as well. We evaluate which mechanisms might be responsible for this quenching process. The presence of type 2 AGNs plays a role at damping the sSFR in bulges and less efficiently in disks. Also, the decrease in the sSFR of the disk component becomes more noticeable for stellar masses around 10(10.5) M-circle dot; for bulges, it is already present at similar to 10(9.5) M-circle dot. The analysis of the line-of-sight stellar velocity dispersions (sigma) for the bulge component and of the corresponding Faber-Jackson relation shows that AGNs tend to have slightly higher sigma values than star-forming galaxies for the same mass. Finally, the impact of environment is evaluated by means of the projected galaxy density, Sigma(5). We find that the SFR of both bulges and disks decreases in intermediate- to high-density environments. This work reflects the potential of combining IFS data with 2D multicomponent decompositions to shed light on the processes that regulate the SFR.
© 2017. The American Astronomical Society. All rights reserved. Artículo firmado por 24 autores. This study makes uses of the data provided by the Calar Alto Legacy Integral Field Area (CALIFA) survey ( CALIFA is the first legacy survey being performed at Calar Alto. The CALIFA Collaboration would like to thank the IAA-CSIC and MPIA-MPG as major partners of the observatory, and CAHA itself, for the unique access to telescope time and support in manpower and infrastructures. The CALIFA Collaboration thanks also the CAHA staff for the dedication to this project. We would like to thank A. Aragón Salamanca for useful comments and suggestions. C.C.-T. gratefully acknowledges the support of the Spanish Ministerio de Educación, Cultura y Deporte by means of the FPU Fellowship Program and the Postdoctoral Fellowship of the Youth Employment Initiative (YEI) European Program. The authors also acknowledge the support from the Plan Nacional de Investigación y Desarrollo funding programs, AYA2012-30717 and AyA2013-46724P, of Spanish Ministerio de Economía y Competitividad (MINECO).
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