Examinando por Autor "Zaritsky D."

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    One Hundred SMUDGes in S-PLUS: Ultra-diffuse Galaxies Flourish in the Field
    (Institute of Physics Publishing, 2020-04) Barbosa C.E.; Zaritsky D.; Donnerstein R.; Zhang H.; Dey A.; De Oliveira, C. Mendes; Sampedro L.; Molino A.; Costa-Duarte M.V.; Coelho P.; Cortesi A.; Herpich F.R.; Hernandez-Jimenez J.A.; Santos-Silva T.; Pereira E.; Werle A.; Overzier R.A.; Cid Fernandes R.; Castelli, A. V. Smith; Ribeiro T.; Schoenell W.; Kanaan A.
    We present the first systematic study of the stellar populations of ultra-diffuse galaxies (UDGs) in the field, integrating the large area search and characterization of UDGs by the SMUDGes survey with the twelve-band optical photometry of the S-PLUS survey. Based on Bayesian modeling of the optical colors of UDGs, we determine the ages, metallicities, and stellar masses of 100 UDGs distributed in an area of ∼330 deg2 in the Stripe 82 region. We find that the stellar masses and metallicities of field UDGs are similar to those observed in clusters and follow the trends previously defined in studies of dwarf and giant galaxies. However, field UDGs have younger luminosity-weighted ages than do UDGs in clusters. We interpret this result to mean that field UDGs have more extended star formation histories, including some that continue to form stars at low levels to the present time. Finally, we examine stellar population scaling relations that show that UDGs are, as a population, similar to other low surface brightness galaxies.
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    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)