Enhanced star formation in both disks and ram pressure stripped tails of GASP jellyfish galaxies

TL;DR

This study uses GASP data to show that ram pressure stripping in galaxies can moderately boost star formation in both their disks and tails, challenging previous contradictory predictions.

Contribution

It provides the first statistically significant observational evidence that ram pressure stripping can enhance star formation in galaxy disks and tails.

Findings

Stripping galaxies have higher SFR at given mass compared to controls.

Star formation increases by about 0.2 dex in disks.

Additional star formation occurs in the stripped tails.

Abstract

Exploiting the data from the GAs Stripping Phenomena in galaxies with MUSE (GASP) program, we compare the integrated Star Formation Rate- Mass relation (SFR-M_ast) relation of 42 cluster galaxies undergoing ram pressure stripping ("stripping galaxies") to that of 32 field and cluster undisturbed galaxies. Theoretical predictions have so far led to contradictory conclusions about whether ram pressure can enhance the star formation in the gas disks and tails or not and until now a statistically significant observed sample of stripping galaxies was lacking. We find that stripping galaxies occupy the upper envelope of the control sample SFR-M_ast relation, showing a systematic enhancement of the SFR at any given mass. The star formation enhancement occurs in the disk (0.2 dex), and additional star formation takes place in the tails. Our results suggest that strong ram pressure stripping events can moderately enhance the star formation also in the disk prior to gas removal.