Examinando por Autor "Muzzin A."
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Ítem A Large-scale Kinematic Study of Molecular Gas in High-z Cluster Galaxies: Evidence for High Levels of Kinematic Asymmetry(Institute of Physics, 2023-02-01) Cramer W.J.; Noble A.G.; Massingill K.; Cairns J.; Clements D.L.; Cooper M.C.; Demarco R.; Matharu J.; McDonald M.; Muzzin A.; Nantais J.; Rudnick G.We investigate the resolved kinematics of the molecular gas, as traced by the Atacama Large Millimeter/submillimeter Array in CO (2−1), of 25 cluster member galaxies across three different clusters at a redshift of z ∼ 1.6. This is the first large-scale analysis of the molecular gas kinematics of cluster galaxies at this redshift. By separately estimating the rotation curve of the approaching and receding sides of each galaxy via kinematic modeling, we quantify the difference in total circular velocity to characterize the overall kinematic asymmetry of each galaxy. 3/14 of the galaxies in our sample that we are able to model have similar degrees of asymmetry as that observed in galaxies in the field at similar redshift based on observations of mainly ionized gas. However, this leaves 11/14 galaxies in our sample with significantly higher asymmetry, and some of these galaxies have degrees of asymmetry of up to ∼50 times higher than field galaxies observed at similar redshift. Some of these extreme cases also have one-sided tail-like morphology seen in the molecular gas, supporting a scenario of tidal and/or ram pressure interaction. Such stark differences in the kinematic asymmetry in clusters versus the field suggest the evolutionary influence of dense environments, established as being a major driver of galaxy evolution at low redshift, is also active in the high-redshift universe.Ítem ALMA Observations of Gas-rich Galaxies in z ∼ 1.6 Galaxy Clusters: Evidence for Higher Gas Fractions in High-density Environments(Institute of Physics Publishing, 2017-06) Noble A.G.; Donald M.; Muzzin A.; Nantais J.; Rudnick G.; Van Kampen E.; Webb T.M.A.; Wilson G.; Yee H.K.C.; Boone K.; Cooper M.C.; DeGroot A.; Delahaye A.; Demarco R.; Foltz R.; Hayden B.; Lidman C.; Manilla-Robles A.; Perlmutter S.We present ALMA CO (2-1) detections in 11 gas-rich cluster galaxies at z ∼ 1.6, constituting the largest sample of molecular gas measurements in z > 1.5 clusters to date. The observations span three galaxy clusters, derived from the Spitzer Adaptation of the Red-sequence Cluster Survey. We augment the >5σ detections of the CO (2-1) fluxes with multi-band photometry, yielding stellar masses and infrared-derived star formation rates, to place some of the first constraints on molecular gas properties in z ∼ 1.6 cluster environments. We measure sizable gas reservoirs of 0.5-2 × 1011 M in these objects, with high gas fractions (f gas) and long depletion timescales (τ), averaging 62% and 1.4 Gyr, respectively. We compare our cluster galaxies to the scaling relations of the coeval field, in the context of how gas fractions and depletion timescales vary with respect to the star-forming main sequence. We find that our cluster galaxies lie systematically off the field scaling relations at z = 1.6 toward enhanced gas fractions, at a level of ∼4σ, but have consistent depletion timescales. Exploiting CO detections in lower-redshift clusters from the literature, we investigate the evolution of the gas fraction in cluster galaxies, finding it to mimic the strong rise with redshift in the field. We emphasize the utility of detecting abundant gas-rich galaxies in high-redshift clusters, deeming them as crucial laboratories for future statistical studies. © 2017. The American Astronomical Society. All rights reserved.Ítem The Evolution of Environmental Quenching Timescales to z ∼ 1.6: Evidence for Dynamically Driven Quenching of the Cluster Galaxy Population(Institute of Physics Publishing, 2018-10) Foltz R.; Wilson G.; Muzzin A.; Cooper M.C.; Nantais J.; Van Der Burg R.F.J.; Cerulo P.; Chan J.; Fillingham S.P.; Surace J.; Webb T.; Noble A.; McDonald M.; Rudnick G.; Lidman C.; Demarco R.; Hlavacek-Larrondo J.; Yee H.K.C.; Perlmutter S.; Hayden B.Using a sample of four galaxy clusters at 1.35 < z < 1.65 and 10 galaxy clusters at 0.85 < z < 1.35, we measure the environmental quenching timescale, t Q, corresponding to the time required after a galaxy is accreted by a cluster for it to fully cease star formation. Cluster members are selected by a photometric-redshift criterion, and categorized as star-forming, quiescent, or intermediate according to their dust-corrected rest-frame colors and magnitudes. We employ a "delayed-then-rapid" quenching model that relates a simulated cluster mass accretion rate to the observed numbers of each type of galaxy in the cluster to constrain t Q. For galaxies of mass M ∗ 1010.5 M o, we find a quenching timescale of t Q = Gyr in the z ∼ 1.5 cluster sample, and Gyr at z ∼ 1. Using values drawn from the literature, we compare the redshift evolution of t Q to timescales predicted for different physical quenching mechanisms. We find t Q to depend on host halo mass such that quenching occurs over faster timescales in clusters relative to groups, suggesting that properties of the host halo are responsible for quenching high-mass galaxies. Between z = 0 and z = 1.5, we find that t Q evolves faster than the molecular gas depletion timescale and slower than an estimated star formation rate-outflow timescale, but is consistent with the evolution of the dynamical time. This suggests that environmental quenching in these galaxies is driven by the motion of satellites relative to the cluster environment, although due to uncertainties in the atomic gas budget at high redshift, we cannot rule out quenching due to simple gas depletion. © 2018. The American Astronomical Society. All rights reserved..Ítem The GOGREEN survey: Post-infall environmental quenching fails to predict the observed age difference between quiescent field and cluster galaxies at z > 1(Oxford University Press, 2020-11) Webb K.; Balogh M.L.; Leja J.; van der Burg R.F.J.; Rudnick G.; Muzzin A.; Boak K.; Cerulo P.; Gilbank D.; Lidman C.; Old L.J.; Pintos-Castro I.; McGee S.; Shipley H.; Biviano A.; Chan J.C.C.; Cooper M.; de Lucia G.; Demarco R.; Forrest B.; Jablonka P.; Kukstas E.; McCarthy I.G.; McNab K.; Nantais J.; Noble A.; Poggianti B.; Reeves A.M.M.; Vulcani B.; Wilson G.; Yee H.K.C.; Zaritsky D.We study the star formation histories (SFHs) and mass-weighted ages of 331 UVJ-selected quiescent galaxies in 11 galaxy clusters and in the field at 1 < z < 1.5 from the Gemini Observations of Galaxies in Rich Early ENvironments (GOGREEN) survey. We determine the SFHs of individual galaxies by simultaneously fitting rest-frame optical spectroscopy and broadband photometry to stellar population models. We confirm that the SFHs are consistent with more massive galaxies having on average earlier formation times. Comparing galaxies found in massive clusters with those in the field, we find galaxies with M∗ < 1011.3 M in the field have more extended SFHs. From the SFHs we calculate the mass-weighted ages, and compare age distributions of galaxies between the two environments, at fixed mass. We constrain the difference in mass-weighted ages between field and cluster galaxies to 0.31+0.51−0.33 Gyr, in the sense that cluster galaxies are older. We place this result in the context of two simple quenching models and show that neither environmental quenching based on time since infall (without pre-processing) nor a difference in formation times alone can reproduce both the average age difference and relative quenched fractions. This is distinctly different from local clusters, for which the majority of the quenched population is consistent with having been environmentally quenched upon infall. Our results suggest that quenched population in galaxy clusters at z > 1 has been driven by different physical processes than those at play at z = 0. © 2020 The Author(s)Ítem The H α star formation main sequence in cluster and field galaxies at z ∼1.6(Oxford University Press, 2020-12) Nantais J.; Wilson G.; Muzzin A.; Old L.J.; Demarco R.; Cerulo P.; Balogh M.; Rudnick G.; Chan J.; Cooper M.C.; Forrest B.; Hayden B.; Lidman C.; Noble A.; Perlmutter S.; Rhea C.; Surace J.; Van Der Burg R.; Van Kampen E.We calculate H α-based star formation rates and determine the star formation rate-stellar mass relation for members of three Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS) clusters at z ∼1.6 and serendipitously identified field galaxies at similar redshifts to the clusters. We find similar star formation rates in cluster and field galaxies throughout our range of stellar masses. The results are comparable to those seen in other clusters at similar redshifts, and consistent with our previous photometric evidence for little quenching activity in clusters. One possible explanation for our results is that galaxies in our z ∼1.6 clusters have been accreted too recently to show signs of environmental quenching. It is also possible that the clusters are not yet dynamically mature enough to produce important environmental quenching effects shown to be important at low redshift, such as ram-pressure stripping or harassment. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.