Examinando por Autor "Gilbank, David"

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    The GOGREEN Survey: A deep stellar mass function of cluster galaxies at 1.0 < z < 1.4 and the complex nature of satellite quenching
    (EDP Sciences, 2020-06-01) van der Burg, Remco F. J.; Rudnick, Gregory; Balogh, Michael L.; Muzzin, Adam; Lidman, Chris; Old, Lyndsay J.; Shipley, Heath; Gilbank, David; McGee, Sean; Biviano, Andrea; Cerulo, Pierluigi; Chan, Jeffrey C. C.; Cooper, Michael; De Lucia, Gabriella; Demarco, Ricardo; Forrest, Ben; Gwyn, Stephen; Jablonka, Pascale; Kukstas, Egidijus; Marchesini, Danilo; Nantais, Julie; Noble, Allison; Pintos-Castro, Irene; Poggianti, Bianca; Reeves, Andrew M. M.; Stefanon, Mauro; Vulcani, Benedetta; Webb, Kristi; Wilson, Gillian; Yee, Howard; Zaritsky, Dennis
    We study the stellar mass functions (SMFs) of star-forming and quiescent galaxies in 11 galaxy clusters at 1.0 < z < 1.4 drawn from the Gemini Observations of Galaxies in Rich Early ENvironments (GOGREEN) survey. Based on more than 500 h of Gemini/GMOS spectroscopy and deep multi-band photometry taken with a range of observatories, we probe the SMFs down to a stellar mass limit of 109.7 M (109.5 M for star-forming galaxies). At this early epoch, the fraction of quiescent galaxies is already highly elevated in the clusters compared to the field at the same redshift. The quenched fraction excess (QFE) represents the fraction of galaxies that would be star-forming in the field but are quenched due to their environment. The QFE is strongly mass dependent, and increases from ∼30% at M? = 109.7 M to ∼80% at M? = 1011.0 M . Nonetheless, the shapes of the SMFs of the two individual galaxy types, star-forming and quiescent galaxies, are identical between cluster and field to high statistical precision. Nevertheless, along with the different quiescent fractions, the total galaxy SMF is also environmentally dependent, with a relative deficit of low-mass galaxies in the clusters. These results are in stark contrast with findings in the local Universe, and therefore require a substantially different quenching mode to operate at early times. We discuss these results in light of several popular quenching models.
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    VLT/MAGELLAN SPECTROSCOPY of 29 STRONG LENSING SELECTED GALAXY CLUSTERS
    (Institute of Physics Publishing, 2017-01) Carrasco, Mauricio; Barrientos, L. Felipe; Anguita, Timo; García-Vergara, Cristina; Bayliss, Matthew; Gladders, Michael; Gilbank, David; Yee H.K.C.; West, Michael
    We present an extensive spectroscopic follow-up campaign of 29 strong lensing (SL) selected galaxy clusters discovered primarily in the Second Red-Sequence Cluster Survey (RCS-2). Our spectroscopic analysis yields redshifts for 52 gravitational arcs present in the core of our galaxy clusters, which correspond to 35 distinct background sources that are clearly distorted by the gravitational potential of these clusters. These lensed galaxies span a wide redshift range of 0.8 ≤ z ≤ 2.9, with a median redshift of z s = 1.8 ± 0.1. We also measure reliable redshifts for 1004 cluster members, allowing us to obtain robust velocity dispersion measurements for 23 of these clusters, which we then use to determine their dynamical masses by using a simulation-based σ DM - M 200 scaling relation. The redshift and mass ranges covered by our SL sample are 0.22 ≤ z ≤ 1.01 and , respectively. We analyze and quantify some possible effects that might bias our mass estimates, such as the presence of substructure, the region where cluster members are selected for spectroscopic follow-up, the final number of confirmed members, and line-of-sight effects. We find that 10 clusters of our sample with N mem 20 show signs of dynamical substructure. However, the velocity data of only one system is inconsistent with a uni-modal distribution. We therefore assume that the substructures are only marginal and not of comparable size to the clusters themselves. Consequently, our velocity dispersion and mass estimates can be used as priors for SL mass reconstruction studies and also represent an important step toward a better understanding of the properties of the SL galaxy cluster population. © 2017. The American Astronomical Society. All rights reserved.