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The role of secular evolution in the black hole growth of narrow-line Seyfert 1 galaxies

Authors

  • G. Orban de Xivry,

    Corresponding author
    1. Max Planck Institut für extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching, Germany
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  • R. Davies,

    1. Max Planck Institut für extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching, Germany
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  • M. Schartmann,

    1. Max Planck Institut für extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching, Germany
    2. Universitäts-Sternwarte München, Scheinerstrasse 1, D-81679 München, Germany
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  • S. Komossa,

    1. Max Planck Institut für extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching, Germany
    2. Technische Universität München, Fakultät für Physik, James-Franck-Strasse, D-85748 Garching, Germany
    3. Excellence Cluster Universe, TUM, Boltzmannstrasse 2, D-85748 Garching, Germany
    4. Max Planck Institut für Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching, Germany
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  • A. Marconi,

    1. Dipartimento di Fisica e Astronomia, Universitá degli Studi di Firenze, Largo E. Fermi 2, 50125 Firenze, Italy
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  • E. Hicks,

    1. Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA
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  • H. Engel,

    1. Max Planck Institut für extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching, Germany
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  • L. Tacconi

    1. Max Planck Institut für extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching, Germany
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E-mail: xivry@mpe.mpg.de

ABSTRACT

Narrow-line Seyfert 1 (NLS1) galaxies show extreme properties with respect to the other Seyfert galaxies. Indeed, they are thought to be accreting at Eddington rates and to possess low-mass black holes. Therefore, they may represent a key class of objects for understanding the co-evolution of black holes and their host galaxies. We propose that NLS1s represent a class of active galactic nucleus in which the black hole growth is, and has always been, dominated by secular evolution. First, by looking at the NLS1 host galaxy properties in the literature, we show that the evolution of NLS1s is presently driven by secular processes, much more so than for broad-line Seyfert 1s (BLS1s). Secondly, we study the bulges of NLS1 and BLS1 galaxies. Our results demonstrate that NLS1 host bulges are pseudo-bulges and are statistically different from BLS1 bulges. This difference points to the particular importance of secular processes in the past evolution of their hosts. We build on this result to understand the implications on their evolution and the duration of their duty cycle. We show that NLS1s are not necessarily in a special phase of black hole growth and that several Gyr are required for their black hole masses to become similar to BLS1s. Finally, in the light of our results, we discuss the location of NLS1 galaxies on the MBH–σ plane and speculate about the connection between the NLS1 galaxy properties and their black hole spin.

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