Star Formation in CALIFA survey perturbed galaxies. I. Effects of Tidal
  Interactions
  We explore the effects of tidal interactions on star formation (SF) by
analysing a sample of CALIFA survey galaxies. The sample consists of tidally
and non-tidally perturbed galaxies, paired at the closest stellar mass
densities for the same galaxy type between subsamples. They are then compared,
both on the resolved Star Formation Main Sequence (SFMS) plane and in annular
property profiles. Star-forming regions in tidally perturbed galaxies exhibit
flatter SFMS slopes compared to star-forming regions in non-tidally perturbed
galaxies. Despite that the annular profiles show star-forming regions in
tidally perturbed galaxies as being mostly older, their SF properties are never
reduced against those ones proper of non-tidally perturbed galaxies.
Star-forming regions in non-tidally perturbed galaxies are better candidates
for SF suppression (quenching). The lowered SF with increasing stellar mass
density in tidally perturbed galaxies may suggest a lower dependence of SF on
stellar mass. Though the SFMS slopes, either flatter or steeper, are found
independent of stellar mass density, the effect of global stellar mass can not
be ignored when distinguishing among galaxy types. Since a phenomenon or
property other than local/global stellar mass may be taking part in the
modulation of SF, the integrated SF properties are related to the tidal
perturbation parameter. We find weak, but detectable, positive correlations for
perturbed galaxies suggesting that tidal perturbations induced by close
companions increase the gas accretion rates of these objects.
