H α 3: an H α imaging survey of HI selected galaxies from ALFALFA IV. Structure of galaxies in the Local and Coma superclusters

• Published in: Astronomy and astrophysics (Berlin) Vol. 553; pp. 1 - 15
• Main Authors: Fossati, M, Gavazzi, G, Savorgnan, G, Fumagalli, M, Boselli, A, Gutierrez, L, Toledo, H Hernandez, Giovanelli, R, Haynes, M P
• Format: Journal Article
• Language: English
• Published: EDP Sciences 01.05.2013
• Subjects: Alfalfa; Astronomy; Astrophysics; Coma; Galactic superclusters; Galaxies; Imaging; Quenching; Sciences of the Universe; Star formation
• ISSN: 0004-6361; 1432-0746; 1432-0756
• DOI: 10.1051/0004-6361/201220915

We present the analysis of the galaxy structural parameters from H alpha 3, an H alpha narrow-band imaging follow-up survey of ~800 galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA) in the Local supercluster, including the Virgo cluster, and in the Coma supercluster. Taking advantage of H alpha 3, which provides the complete census of the recent star-forming, HI-rich galaxies in the local universe, we aim to investigate the structural parameters of the young and the old stellar populations. By comparing the sizes of these stellar components, we investigated the spatial scale on which galaxies are growing at the present cosmological epoch and the role of the environment in quenching the star-formation activity. Irrespective of whether we used the ratio between effective radii or the EW/r parameter, we found that the concentration index is the main parameter that describes the current growth of isolated galaxies but, for a fixed concentration, the stellar mass plays a second-order role. At the present epoch, massive galaxies are growing inside-out, conversely, the dwarfs are growing on the scale of their already assembled mass.