OMEGA – OSIRIS mapping of emission-line galaxies in A901/2 : III. Galaxy properties across projected phase space in A901/2

• Autor(a) principal: Weinzirl, Timothy
• Data de Publicação: 2017
• Outros Autores: Aragón-Salamanca, Alfonso, Gray, Meghan E., Bamford, Steven Peter, Rodríguez del Pino, Bruno, Chies-Santos, Ana Leonor, Böhm, Asmus, Wolf, Christian, Cool, Richard J.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/170580
• topic: Metalicidade; Mapeamentos astronômicos; Nucleo galatico; Deslocamento para o vermelho; Instrumentation: interferometers; Galaxies: clusters: individual: A901/2; Galaxies: distances and redshifts; Galaxies: star formation

We conduct a comprehensive projected phase-space analysis of the A901/2 multicluster system at z ∼ 0.165. Aggregating redshifts from spectroscopy, tunable-filter imaging and prism techniques, we assemble a sample of 856 cluster galaxies reaching 108.5M in stellar mass. We look for variations in cluster galaxy properties between virialized and non-virialized regions of projected phase space (PPS). Our main conclusions point to relatively gentle environmental effects, expressedmainly on galaxy gas reservoirs. (1) Stacking the four subclusters in A901/2, we find galaxies in the virialized region are more massive, redder and have marginally higher S´ersic indices, but their half-light radii and Hubble types are not significantly different. (2) After accounting for trends in stellar mass, there is a remaining change in rest-frame colour across PPS. Primarily, the colour difference is due to the absence in the virialized region of galaxies with rest frame B − V < 0.7 and moderate-to-high (M > 109.85 M ) stellar mass. (3) There is an infalling population of lower mass (M ≤ 109.85 M ), relatively blue (B − V < 0.7) elliptical or spheroidal galaxies that are strikingly absent in the virialized region. (4) The number of bona fide star-forming and active galactic nucleus galaxies in the PPS regions is strongly dictated by stellar mass. However, there remains a reduced fraction of star-forming galaxies in the centres of the clusters at fixed stellar mass, consistent with the star formation–density relation in galaxy clusters. (5) There is no change in specific Hα-derived star formation rates of star-forming galaxies at fixed mass across the cluster environment. This suggests that pre-processing of galaxies during infall plays a prominent role in quenching star formation.