Morphometry as a probe of the evolution of jellyfish galaxies: evidence of broadening in the surface brightness profiles of ram-pressure stripping candidates in the multicluster system A901/A902

Abstract

We explore the morphometric properties of a group of 73 ram pressure stripping candidates in the A901/A902 multi-cluster system, at z$\sim$0.165, to characterise the morphologies and structural evolution of jellyfish galaxies. By employing a quantitative measurement of morphometric indicators with the algorithm \textsc{morfometryka} on Hubble Space Telescope (F606W) images of the galaxies, we present a novel morphology-based method for determining trail vectors. We study the surface brightness profiles and curvature of the candidates and compare the results obtained with two analysis packages, \textsc{morfometryka} and \textsc{iraf/ellipse} on retrieving information of the irregular structures present in the galaxies. Our morphometric analysis shows that the ram pressure stripping candidates have peculiar concave regions in their surface brightness profiles. Therefore, these profiles are less concentrated (lower Sersic indices) than other star forming galaxies that do not show morphological features of ram pressure stripping. In combination with morphometric trail vectors, this feature could both help identify galaxies undergoing ram-pressure stripping and reveal spatial variations in the star formation rate.