Mon. Not. R. Astron. Soc., 471, 182-200 (2017/October-2)
OMEGA - OSIRIS Mapping of Emission-line Galaxies in A901/2 - III. Galaxy properties across projected phase space in A901/2.
WEINZIRL T., ARAGON-SALAMANCA A., GRAY M.E., BAMFORD S.P., RODRIGUEZ DEL PINO B., CHIES-SANTOS A.L., BOHM A., WOLF C. and COOL R.J.
Abstract (from CDS):
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 108.5 M☉ 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, expressed mainly 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 Sersic 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.
© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
instrumentation: interferometers - galaxies: clusters: individual: A901/2 - galaxies: distances and redshifts - galaxies: star formation - galaxies: star formation
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