Ram pressure stripping candidates in the coma cluster: evidence for enhanced star formation

ABSTRACT The Coma cluster is the nearest massive ($M \gtrsim 10^{15}\, \mathrm{M_\odot }$) galaxy cluster, making it an excellent laboratory to probe the influence of the cluster environment on galaxy star formation. Here, we present a sample of 41 galaxies with disturbed morphologies consistent with ram pressure stripping. These galaxies are identified visually using high-quality, multiband imaging from the Canada–France–Hawaii telescope covering ${\sim}9\, \mathrm{deg^2}$ of the Coma cluster. These ‘stripping candidates’ are clear outliers in common quantitative morphological measures, such as concentration-asymmetry and Gini-M20, confirming their disturbed nature. Based on the orientations of observed asymmetries, as well as the galaxy positions in projected phase space, these candidates are consistent with galaxies being stripped shortly after infall on to the Coma cluster. Finally, the stripping candidates show enhanced star formation rates, both relative to ‘normal’ star-forming Coma galaxies and isolated galaxies in the field. Ram pressure is likely driving an enhancement in star formation during the stripping phase, prior to quenching. On the whole, ram pressure stripping appears to be ubiquitous across all regions of the Coma cluster.