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The 2dF Galaxy Redshift Survey: the local E+A galaxy population

Blake, Chris ; Pracy, Michael B. ; Couch, Warrick J. ; Bekki, Kenji ; Lewis, Ian ; Glazebrook, Karl ; Baldry, Ivan K. ; Baugh, Carlton M. ; Bland-Hawthorn, Joss ; Bridges, Terry ; Cannon, Russell ; Cole, Shaun ; Colless, Matthew ; Collins, Chris ; Dalton, Gavin ; De Propris, Roberto ; Driver, Simon P. ; Efstathiou, George ; Ellis, Richard S. ; Frenk, Carlos S. ; Jackson, Carole ; Lahav, Ofer ; Lumsden, Stuart ; Maddox, Steve ; Madgwick, Darren ; Norberg, Peder ; Peacock, John A. ; Peterson, Bruce A. ; Sutherland, Will ; Taylor, Keith

In: Monthly Notices of the Royal Astronomical Society, 2004, vol. 355, no. 3, p. 713-727

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    Titre
    • The 2dF Galaxy Redshift Survey: the local E+A galaxy population
    Auteur
    • Blake, Chris. School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
    • Pracy, Michael B.. School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
    • Couch, Warrick J.. School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
    • Bekki, Kenji. School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
    • Lewis, Ian. Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH
    • Glazebrook, Karl. Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD 21118-2686, USA
    • Baldry, Ivan K.. Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD 21118-2686, USA
    • Baugh, Carlton M.. Department of Physics, University of Durham, South Road, Durham DH1 3LE
    • Bland-Hawthorn, Joss. Anglo-Australian Observatory, PO Box 296, Epping, NSW 2111, Australia
    • Bridges, Terry. Anglo-Australian Observatory, PO Box 296, Epping, NSW 2111, Australia
    • Cannon, Russell. Anglo-Australian Observatory, PO Box 296, Epping, NSW 2111, Australia
    • Cole, Shaun. Department of Physics, University of Durham, South Road, Durham DH1 3LE
    • Colless, Matthew. Research School of Astronomy & Astrophysics, The Australian National University, Weston Creek, ACT 2611, Australia
    • Collins, Chris. Astrophysics Research Institute, Liverpool John Moores University, 12 Quays House, Birkenhead L14 1LD
    • Dalton, Gavin. Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH
    • De Propris, Roberto. Research School of Astronomy & Astrophysics, The Australian National University, Weston Creek, ACT 2611, Australia
    • Driver, Simon P.. Research School of Astronomy & Astrophysics, The Australian National University, Weston Creek, ACT 2611, Australia
    • Efstathiou, George. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA
    • Ellis, Richard S.. Department of Astronomy, California Institute of Technology, Pasadena, CA 91025, USA
    • Frenk, Carlos S.. Department of Physics, University of Durham, South Road, Durham DH1 3LE
    • Jackson, Carole. CSIRO Australia Telescope National Facility, PO Box 76, Epping, NSW 1710, Australia
    • Lahav, Ofer. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA
    • Lumsden, Stuart. Department of Physics, University of Leeds, Woodhouse Lane, Leeds LS2 9JT
    • Maddox, Steve. School of Physics & Astronomy, University of Nottingham, Nottingham NG7 2RD
    • Madgwick, Darren. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
    • Norberg, Peder. ETHZ Institut für Astronomie, HPF G3.1, ETH Honggerberg, CH-8093 Zurich, Switzerland
    • Peacock, John A.. Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ
    • Peterson, Bruce A.. Research School of Astronomy & Astrophysics, The Australian National University, Weston Creek, ACT 2611, Australia
    • Sutherland, Will. Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ
    • Taylor, Keith. Department of Astronomy, California Institute of Technology, Pasadena, CA 91025, USA
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Monthly Notices of the Royal Astronomical Society, 2004, vol. 355, no. 3, p. 713-727. Blackwell Science Ltd
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:291120
    Summary
    We select a sample of low-redshift (z∼ 0.1) E+A galaxies from the 2dF Galaxy Redshift Survey (2dFGRS). The spectra of these objects are defined by strong hydrogen Balmer absorption lines (Hδ, Hγ, Hβ) combined with a lack of [O ii] 3727-Å emission, together implying a recently truncated burst of star formation. The E+A spectrum is thus a signpost to galaxies in the process of evolution. We quantify the local environments, clustering properties and luminosity function of the E+A galaxies. We find that the environments are consistent with the ensemble of 2dFGRS galaxies: low-redshift E+A systems are located predominantly in the field, existing as isolated objects or in poor groups. However, the luminosity distribution of galaxies selected using three Balmer absorption lines Hδγβ appears more typical of ellipticals. Indeed, morphologically these galaxies are preferentially spheroidal (E/S0) systems. In a small but significant number we find evidence for recent major mergers, such as tidal tails. We infer that major mergers are one important formation mechanism for E+A galaxies, as suggested by previous studies. At low redshift the merger probability is high in the field and low in clusters, thus these recently formed spheroidal systems do not follow the usual morphology-density relation for ellipticals. Regarding the selection of E+A galaxies: we find that basing the Balmer-line criterion solely on Hδ absorption leads to a significant subpopulation of disc systems with detectable Hα emission. In these objects the [O ii] emission is presumably either obscured by dust or present with a low signal-to-noise ratio, whilst the (Hγ, Hβ) absorption features are subject to emission-filling