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Title: MASS AND ENVIRONMENT AS DRIVERS OF GALAXY EVOLUTION IN SDSS AND zCOSMOS AND THE ORIGIN OF THE SCHECHTER FUNCTION

Abstract

We explore the simple inter-relationships between mass, star formation rate, and environment in the SDSS, zCOSMOS, and other deep surveys. We take a purely empirical approach in identifying those features of galaxy evolution that are demanded by the data and then explore the analytic consequences of these. We show that the differential effects of mass and environment are completely separable to z {approx} 1, leading to the idea of two distinct processes of 'mass quenching' and 'environment quenching'. The effect of environment quenching, at fixed over-density, evidently does not change with epoch to z {approx} 1 in zCOSMOS, suggesting that the environment quenching occurs as large-scale structure develops in the universe, probably through the cessation of star formation in 30%-70% of satellite galaxies. In contrast, mass quenching appears to be a more dynamic process, governed by a quenching rate. We show that the observed constancy of the Schechter M* and {alpha}{sub s} for star-forming galaxies demands that the quenching of galaxies around and above M* must follow a rate that is statistically proportional to their star formation rates (or closely mimic such a dependence). We then postulate that this simple mass-quenching law in fact holds over a much broader rangemore » of stellar mass (2 dex) and cosmic time. We show that the combination of these two quenching processes, plus some additional quenching due to merging naturally produces (1) a quasi-static single Schechter mass function for star-forming galaxies with an exponential cutoff at a value M* that is set uniquely by the constant of proportionality between the star formation and mass quenching rates and (2) a double Schechter function for passive galaxies with two components. The dominant component (at high masses) is produced by mass quenching and has exactly the same M* as the star-forming galaxies but a faint end slope that differs by {Delta}{alpha}{sub s} {approx} 1. The other component is produced by environment effects and has the same M* and {alpha}{sub s} as the star-forming galaxies but an amplitude that is strongly dependent on environment. Subsequent merging of quenched galaxies will modify these predictions somewhat in the denser environments, mildly increasing M* and making {alpha}{sub s} slightly more negative. All of these detailed quantitative inter-relationships between the Schechter parameters of the star-forming and passive galaxies, across a broad range of environments, are indeed seen to high accuracy in the SDSS, lending strong support to our simple empirically based model. We find that the amount of post-quenching 'dry merging' that could have occurred is quite constrained. Our model gives a prediction for the mass function of the population of transitory objects that are in the process of being quenched. Our simple empirical laws for the cessation of star formation in galaxies also naturally produce the 'anti-hierarchical' run of mean age with mass for passive galaxies, as well as the qualitative variation of formation timescale indicated by the relative {alpha}-element abundances.« less

Authors:
; ; ; ; ; ; ;  [1]; ; ;  [2];  [3]; ; ;  [4];  [5];  [6];  [7];  [8];  [9]
  1. Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-strasse 27, 8093 Zurich (Switzerland)
  2. INAF Osservatorio Astronomico di Bologna, Via Ranzani 1, 40127 Bologna (Italy)
  3. INAF Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122, Padova (Italy)
  4. Laboratoire d'Astrophysique de Marseille, 38, rue Frederic Joliot-Curie, 13388 Marseille Cedex 13 (France)
  5. INAF Osservatorio Astronomico di Brera, via Brera 28, 20121 Milano (Italy)
  6. INAF-IASF Milano, Via East Bassini 15, 20133 Milano (Italy)
  7. University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822-1839 (United States)
  8. Department of Astronomy, Caltech, MC 105-24, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
  9. Laboratoire d'Astrophysique de Toulouse/Tarbes, Universite de Toulouse, 14 avenue Edouard Belin, 31400 Toulouse (France)
Publication Date:
OSTI Identifier:
21464868
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 721; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/721/1/193; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGY; ELEMENT ABUNDANCE; GALACTIC EVOLUTION; GALAXIES; MASS; RED SHIFT; SATELLITES; STAR EVOLUTION; STARS; UNIVERSE; ABUNDANCE; EVOLUTION

Citation Formats

Yingjie, Peng, Lilly, Simon J, Kovac, Katarina, Knobel, Christian, Maier, Christian, Carollo, C Marcella, Silverman, John, Kampczyk, Pawel, Bolzonella, Micol, Pozzetti, Lucia, Zamorani, Gianni, Renzini, Alvio, Ilbert, Olivier, Cucciati, Olga, De Ravel, Loic, Iovino, Angela, Tasca, Lidia, Sanders, David, Scoville, Nicholas, and Contini, Thierry. MASS AND ENVIRONMENT AS DRIVERS OF GALAXY EVOLUTION IN SDSS AND zCOSMOS AND THE ORIGIN OF THE SCHECHTER FUNCTION. United States: N. p., 2010. Web. doi:10.1088/0004-637X/721/1/193.
Yingjie, Peng, Lilly, Simon J, Kovac, Katarina, Knobel, Christian, Maier, Christian, Carollo, C Marcella, Silverman, John, Kampczyk, Pawel, Bolzonella, Micol, Pozzetti, Lucia, Zamorani, Gianni, Renzini, Alvio, Ilbert, Olivier, Cucciati, Olga, De Ravel, Loic, Iovino, Angela, Tasca, Lidia, Sanders, David, Scoville, Nicholas, & Contini, Thierry. MASS AND ENVIRONMENT AS DRIVERS OF GALAXY EVOLUTION IN SDSS AND zCOSMOS AND THE ORIGIN OF THE SCHECHTER FUNCTION. United States. https://doi.org/10.1088/0004-637X/721/1/193
Yingjie, Peng, Lilly, Simon J, Kovac, Katarina, Knobel, Christian, Maier, Christian, Carollo, C Marcella, Silverman, John, Kampczyk, Pawel, Bolzonella, Micol, Pozzetti, Lucia, Zamorani, Gianni, Renzini, Alvio, Ilbert, Olivier, Cucciati, Olga, De Ravel, Loic, Iovino, Angela, Tasca, Lidia, Sanders, David, Scoville, Nicholas, and Contini, Thierry. 2010. "MASS AND ENVIRONMENT AS DRIVERS OF GALAXY EVOLUTION IN SDSS AND zCOSMOS AND THE ORIGIN OF THE SCHECHTER FUNCTION". United States. https://doi.org/10.1088/0004-637X/721/1/193.
@article{osti_21464868,
title = {MASS AND ENVIRONMENT AS DRIVERS OF GALAXY EVOLUTION IN SDSS AND zCOSMOS AND THE ORIGIN OF THE SCHECHTER FUNCTION},
author = {Yingjie, Peng and Lilly, Simon J and Kovac, Katarina and Knobel, Christian and Maier, Christian and Carollo, C Marcella and Silverman, John and Kampczyk, Pawel and Bolzonella, Micol and Pozzetti, Lucia and Zamorani, Gianni and Renzini, Alvio and Ilbert, Olivier and Cucciati, Olga and De Ravel, Loic and Iovino, Angela and Tasca, Lidia and Sanders, David and Scoville, Nicholas and Contini, Thierry},
abstractNote = {We explore the simple inter-relationships between mass, star formation rate, and environment in the SDSS, zCOSMOS, and other deep surveys. We take a purely empirical approach in identifying those features of galaxy evolution that are demanded by the data and then explore the analytic consequences of these. We show that the differential effects of mass and environment are completely separable to z {approx} 1, leading to the idea of two distinct processes of 'mass quenching' and 'environment quenching'. The effect of environment quenching, at fixed over-density, evidently does not change with epoch to z {approx} 1 in zCOSMOS, suggesting that the environment quenching occurs as large-scale structure develops in the universe, probably through the cessation of star formation in 30%-70% of satellite galaxies. In contrast, mass quenching appears to be a more dynamic process, governed by a quenching rate. We show that the observed constancy of the Schechter M* and {alpha}{sub s} for star-forming galaxies demands that the quenching of galaxies around and above M* must follow a rate that is statistically proportional to their star formation rates (or closely mimic such a dependence). We then postulate that this simple mass-quenching law in fact holds over a much broader range of stellar mass (2 dex) and cosmic time. We show that the combination of these two quenching processes, plus some additional quenching due to merging naturally produces (1) a quasi-static single Schechter mass function for star-forming galaxies with an exponential cutoff at a value M* that is set uniquely by the constant of proportionality between the star formation and mass quenching rates and (2) a double Schechter function for passive galaxies with two components. The dominant component (at high masses) is produced by mass quenching and has exactly the same M* as the star-forming galaxies but a faint end slope that differs by {Delta}{alpha}{sub s} {approx} 1. The other component is produced by environment effects and has the same M* and {alpha}{sub s} as the star-forming galaxies but an amplitude that is strongly dependent on environment. Subsequent merging of quenched galaxies will modify these predictions somewhat in the denser environments, mildly increasing M* and making {alpha}{sub s} slightly more negative. All of these detailed quantitative inter-relationships between the Schechter parameters of the star-forming and passive galaxies, across a broad range of environments, are indeed seen to high accuracy in the SDSS, lending strong support to our simple empirically based model. We find that the amount of post-quenching 'dry merging' that could have occurred is quite constrained. Our model gives a prediction for the mass function of the population of transitory objects that are in the process of being quenched. Our simple empirical laws for the cessation of star formation in galaxies also naturally produce the 'anti-hierarchical' run of mean age with mass for passive galaxies, as well as the qualitative variation of formation timescale indicated by the relative {alpha}-element abundances.},
doi = {10.1088/0004-637X/721/1/193},
url = {https://www.osti.gov/biblio/21464868}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 721,
place = {United States},
year = {Mon Sep 20 00:00:00 EDT 2010},
month = {Mon Sep 20 00:00:00 EDT 2010}
}