NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-04-23 T02:35:23 PDT
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For refcode 2015ApJ...806..101H:
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2015ApJ...806..101H LoCuSS: The Slow Quenching of Star Formation in Cluster Galaxies and the Need for Pre-processing Haines, C. P.; Pereira, M. J.; Smith, G. P.; Egami, E.; Babul, A.; Finoguenov, A.; Ziparo, F.; McGee, S. L.; Rawle, T. D.; Okabe, N.; Moran, S. M. Abstract. We present a study of the spatial distribution and kinematics of star-forming galaxies in 30 massive clusters at 0.15 < z < 0.30, combining wide-field Spitzer 24 micron and GALEX near-ultraviolet imaging with highly complete spectroscopy of cluster members. The fraction (f_SF_) of star-forming cluster galaxies rises steadily with cluster-centric radius, increasing fivefold by 2r_200_, but remains well below field values even at 3r_200_. This suppression of star formation at large radii cannot be reproduced by models in which star formation is quenched in infalling field galaxies only once they pass within r_200_ of the cluster, but is consistent with some of them being first pre-processed within galaxy groups. Despite the increasing f_SF_-radius trend, the surface density of star-forming galaxies actually declines steadily with radius, falling ~15x from the core to 2r_200_. This requires star formation to survive within recently accreted spirals for 2--3 Gyr to build up the apparent over-density of star-forming galaxies within clusters. The velocity dispersion profile of the star-forming galaxy population shows a sharp peak of 1.44 sigma_nu_ at 0.3r_500_, and is 10%--35% higher than that of the inactive cluster members at all cluster-centric radii, while their velocity distribution shows a flat, top-hat profile within r_500_. All of these results are consistent with star-forming cluster galaxies being an infalling population, but one that must also survive ~0.5--2 Gyr beyond passing within r_200_. By comparing the observed distribution of star-forming galaxies in the stacked caustic diagram with predictions from the Millennium simulation, we obtain a best-fit model in which star formation rates decline exponentially on quenching timescales of 1.73 +/- 0.25 Gyr upon accretion into the cluster. Key words: galaxies: active, galaxies: clusters: general, galaxies: evolution, galaxies: stellar content
Retrieve 30 NED objects in this reference.
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