SDSS-IV MaNGA: The Radial Profile of Enhanced Star Formation in Close Galaxy Pairs

TL;DR

This study analyzes how close galaxy pairs exhibit enhanced central star formation and suppressed outskirts, revealing complex tidal effects that depend on galaxy mass and separation, based on radial sSFR profiles from SDSS-IV MaNGA data.

Contribution

It provides the first detailed analysis of radial sSFR profiles in galaxy pairs, showing mass-independent central enhancement and outskirts suppression, with dependence on mass ratio and separation.

Findings

Central sSFR is enhanced by ~0.3 dex in pairs.

Outskirts sSFR is suppressed by ~0.1 dex.

Enhancement is independent of stellar mass.

Abstract

We compare the radial profiles of the specific star formation rate (sSFR) in a sample of 169 star-forming galaxies in close pairs with those of mass-matched control galaxies in the SDSS-IV MaNGA survey. We find that the sSFR is centrally enhanced (within one effective radius) in interacting galaxies by ~0.3 dex and that there is a weak sSFR suppression in the outskirts of the galaxies of ~0.1 dex. We stack the differences profiles for galaxies in five stellar mass bins between log(M/Mstar) = 9.0-11.5 and find that the sSFR enhancement has no dependence on the stellar mass. The same result is obtained when the comparison galaxies are matched to each paired galaxy in both stellar mass and redshift. In addition, we find that that the sSFR enhancement is elevated in pairs with nearly equal masses and closer projected separations, in agreement with previous work based on single-fiber spectroscopy. We also find that the sSFR offsets in the outskirts of the paired galaxies are dependent on whether the galaxy is the more massive or less massive companion in the pair. The more massive companion experiences zero to a positive sSFR enhancement while the less massive companion experiences sSFR suppression in their outskirts. Our results illustrate the complex tidal effects on star formation in closely paired galaxies.