From fields to a super-cluster: the role of the environment at z=0.84 with HiZELS - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: At z=0, clusters are primarily populated by red, elliptical and massivegalaxies, while blue, spiral and lower-mass galaxies are common in low-densityenvironments. Understanding how and when these differences were established isof absolute importance for our understanding of galaxy formation and evolution,but results at high-z remain contradictory. By taking advantage of the widestand deepest H-alpha narrow-band survey at z=0.84 over the COSMOS and UKIDSS UDSfields, probing a wide range of densities from poor fields to rich groups andclusters, including a confirmed super-cluster with a striking filamentarystructure, we show that the fraction of star-forming galaxies fallscontinuously from ~40% in fields to approaching 0% in rich groups-clusters. Wealso find that the median SFR increases with environmental density, at least upto group densities - but only for low and medium mass galaxies, and thus suchenhancement is mass-dependent at z~1. The environment also plays a role insetting the faint-end slope alpha of the H-alpha luminosity function. Ourfindings provide a sharper view on galaxy formation and evolution and reconcilepreviously contradictory results at z~1: stellar mass is the primary predictorof star formation activity, but the environment also plays a major role.



Autor: David Sobral Edinburgh, Philip Best Edinburgh, Ian Smail Durham, Jim Geach McGill, HiZELS team

Fuente: https://arxiv.org/







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