We explore the role of environment in the evolution of galaxies over 0.1 < z < 0.7 using the final zCOSMOS-bright data set. Using the red fraction of galaxies as a proxy for the quenched population, we find that the fraction of red galaxies increases with the environmental overdensity δ and with the stellar mass M*, consistent with previous works. As at lower redshift, the red fraction appears to be separable in mass and environment, suggesting the action of two processes: mass εm(M*) and environmental ερ(δ) quenching. The parameters describing these appear to be essentially the same at z ∼ 0.7 as locally. We explore the relation between red fraction, mass and environment also for the central and satellite galaxies separately, paying close attention to the effects of impurities in the central-satellite classification and using carefully constructed samples well matched in stellar mass. There is little evidence for a dependence of the red fraction of centrals on overdensity. Satellites are consistently redder at all overdensities, and the satellite quenching efficiency, εsat(δ, M*), increases with overdensity at 0.1 < z < 0.4. This is less marked at higher redshift, but both are nevertheless consistent with the equivalent local measurements. At a given stellar mass, the fraction of galaxies that are satellites, fsat(δ, M*), also increases with overdensity. The obtained ερ(δ)/fsat(δ, M*) agrees well with εsat(δ, M*), demonstrating that the environmental quenching in the overall population is consistent with being entirely produced by a satellite quenching process at least up to z = 0.7. However, despite the unprecedented size of our high-redshift samples, the associated statistical uncertainties are still significant and our statements should be understood as approximations to physical reality, rather than physically exact formulae. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
ZCOSMOS 20k: Satellite galaxies are the main drivers of environmental effects in the galaxy population at least to z ~ 0.7 / Kovač, K; Lilly, S.J.; Knobel, C.; Bschorr, T.J.; Peng, Y.; Carollo, C.M.; Contini, T.; Kneib, J.-P.; Le Févre, O.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Zamorani, G.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Caputi, K.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Kampczyk, P.; Lamareille, F.; Le Borgne, J.-F.; Le Brun, V.; Maier, C.; Mignoli, M.; Oesch, P.; Pello, R.; Perez Montero, E.; Presotto, V.; Silverman, J.; Tanaka, M.; Tasca, L.; Tresse, L.; Vergani, D.; Zucca, E.; Aussel, H.; Koekemoer, A.M.; Le Floc'h, E.; Moresco, M.; Pozzetti, L.. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - STAMPA. - 438:1(2014), pp. 717-738. [10.1093/mnras/stt2241]
ZCOSMOS 20k: Satellite galaxies are the main drivers of environmental effects in the galaxy population at least to z ~ 0.7
RENZINI, ALVIO;ZAMORANI, GIOVANNI;BARDELLI, SANDRO;BOLZONELLA, MICOL;BONGIORNO, ANGELA;CUCCIATI, OLGA;LAMAREILLE, FABRICE;VERGANI, DANIELA;ZUCCA, ELENA;MORESCO, MICHELE ENNIO MARIA;POZZETTI, LUCIA
2014
Abstract
We explore the role of environment in the evolution of galaxies over 0.1 < z < 0.7 using the final zCOSMOS-bright data set. Using the red fraction of galaxies as a proxy for the quenched population, we find that the fraction of red galaxies increases with the environmental overdensity δ and with the stellar mass M*, consistent with previous works. As at lower redshift, the red fraction appears to be separable in mass and environment, suggesting the action of two processes: mass εm(M*) and environmental ερ(δ) quenching. The parameters describing these appear to be essentially the same at z ∼ 0.7 as locally. We explore the relation between red fraction, mass and environment also for the central and satellite galaxies separately, paying close attention to the effects of impurities in the central-satellite classification and using carefully constructed samples well matched in stellar mass. There is little evidence for a dependence of the red fraction of centrals on overdensity. Satellites are consistently redder at all overdensities, and the satellite quenching efficiency, εsat(δ, M*), increases with overdensity at 0.1 < z < 0.4. This is less marked at higher redshift, but both are nevertheless consistent with the equivalent local measurements. At a given stellar mass, the fraction of galaxies that are satellites, fsat(δ, M*), also increases with overdensity. The obtained ερ(δ)/fsat(δ, M*) agrees well with εsat(δ, M*), demonstrating that the environmental quenching in the overall population is consistent with being entirely produced by a satellite quenching process at least up to z = 0.7. However, despite the unprecedented size of our high-redshift samples, the associated statistical uncertainties are still significant and our statements should be understood as approximations to physical reality, rather than physically exact formulae. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
