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Two conditions for galaxy quenching: compact centres and massive haloes

Woo, Joanna ; Dekel, Avishai ; Faber, S. M. ; Koo, David C.

In: Monthly Notices of the Royal Astronomical Society, 2015, vol. 448, no. 1, p. 237-251

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    Titel
    • Two conditions for galaxy quenching: compact centres and massive haloes
    Autor
    • Woo, Joanna. Institute for Astrophysics, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich, Switzerland
    • Dekel, Avishai. Center for Astrophysics and Planetary Science, Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
    • Faber, S. M.. University of California Observatoires/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
    • Koo, David C.. University of California Observatoires/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
    Dokumententyp
    • Postprint
    Sprache
    • Englisch
    Veröffentlicht in
    • Monthly Notices of the Royal Astronomical Society, 2015, vol. 448, no. 1, p. 237-251. Oxford University Press
    Andere elektronische Ausgabe
    OAI-PMH-ID
    • oai:doc.rero.ch:297806
    Summary
    We investigate the roles of two classes of quenching mechanisms for central and satellite galaxies in the Sloan Digital Sky Survey (z<0.075): those involving the halo and those involving the formation of a compact centre. For central galaxies with inner compactness Σ1 kpc∼109-9.4 M⊙ kpc−2, the quenched fraction fq is strongly correlated with Σ1 kpc with only weak halo mass Mh dependence. However, at higher and lower Σ1 kpc, specific star formation rate (sSFR) is a strong function of Mh and mostly independent of Σ1 kpc. In other words, Σ1 kpc∼109-9.4 M⊙ kpc−2 divides galaxies into those with high sSFR below and low sSFR above this range. In both the upper and lower regimes, increasing Mh shifts the entire sSFR distribution to lower sSFR without a qualitative change in shape. This is true even at fixed M*, but varying M* at fixed Mh adds no quenching information. Most of the quenched centrals with Mh>1011.8 M⊙ are dense (Σ1 kpc>109 M⊙ kpc−2), suggesting compaction-related quenching maintained by halo-related quenching. However, 21 per cent are diffuse, indicating only halo quenching. For satellite galaxies in the outskirts of haloes, quenching is a strong function of compactness and a weak function of host Mh. In the inner halo, Mh dominates quenching, with ∼90 per cent of the satellites being quenched once Mh>1013 M⊙. This regional effect is greatest for the least massive satellites. As demonstrated via semi-analytic modelling with simple prescriptions for quenching, the observed correlations can be explained if quenching due to central compactness is rapid while quenching due to halo mass is slow