Investigating the link between inner gravitational potential and star-formation quenching in CALIFA galaxies

It has been suggested that gravitational potential can have a significant role in suppressing star formation in nearby galaxies. To establish observational constraints on this scenario, we investigated the connection between the dynamics - taking the circular velocity curves (CVCs) as a proxy for the inner gravitational potential - and star formation quenching in 215 non-active galaxies across the Hubble sequence from the Calar Alto Legacy Integral Field Area (CALIFA) survey. Our results show that galaxies with similar CVCs tend to have a certain star-formation quenching pattern. To explore these findings in more details, we constructed kiloparsec (kpc) resolved relations of the equivalent width of the H alpha (W-H alpha) versus the amplitude (V-c) and shape (beta = dln V-c/d ln R) of the circular velocity at given radii. We find that the W-H alpha V-c is a declining relationship, where the retired regions of the galaxies (the ones with W-H alpha values of below 3 angstrom) tend to have higher V-c. Concurrently, W-H alpha-beta is a bimodal relationship, which is characterised by two peaks: concentration of the star forming regions at a positive beta (rising CVC) and a second concentration of the retired regions with a negative beta (declining CVC). Our results show that both the amplitude of the CVC - driven by the mass of the galaxies - and its shape - which reflects the internal structure of the galaxies - play an important role in the quenching history of a galaxy.