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Title: AGN in dwarf galaxies: frequency, triggering processes and the plausibility of AGN feedback

Abstract

Abstract While active galactic nuclei (AGN) are considered to be key drivers of the evolution of massive galaxies, their potentially significant role in the dwarf-galaxy regime (M* < 109 M⊙) remains largely unexplored. We combine optical and infrared data, from the Hyper Suprime-Cam (HSC) and the Wide-field Infrared Explorer, respectively, to explore the properties of ∼800 AGN in dwarfs at low redshift (z < 0.3). Infrared-selected AGN fractions are ∼10–30 per cent in dwarfs, which, for reasonable duty cycles, indicates a high black hole (BH)-occupation fraction. Visual inspection of the deep HSC images indicates that the merger fraction in dwarf AGN (∼6 per cent) shows no excess compared to a control sample of non-AGN, suggesting that the AGN-triggering processes are secular in nature. Energetic arguments indicate that, in both dwarfs and massive galaxies, bolometric AGN luminosities (LAGN) are significantly greater than supernova luminosities (LSN). LAGN/LSN is, in fact, higher in dwarfs, with predictions from simulations suggesting that this ratio only increases with redshift. Together with the potentially high BH-occupation fraction, this suggests that if AGN feedback is an important driver of massive-galaxy evolution, the same is likely to be true in the dwarf regime, contrary to our classical thinking.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]
  1. Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
  2. Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH, UK
  3. Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH, UK, Institut d’Astrophysique de Paris (UMR 7095: CNRS and UPMC-Sorbonne Universites), 98 bis bd Arago, F-75014 Paris, France, Laboratoire AIM-Paris-Saclay, CEA/DSM/IRFU, CNRS, University Paris VII, F-91191 Gif-sur-Yvette, France, Department of Physics and Astronomy, The Johns Hopkins University Homewood Campus, Baltimore, MD 21218, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1557364
Resource Type:
Published Article
Journal Name:
Monthly Notices of the Royal Astronomical Society: Letters
Additional Journal Information:
Journal Name: Monthly Notices of the Royal Astronomical Society: Letters Journal Volume: 489 Journal Issue: 1; Journal ID: ISSN 1745-3925
Publisher:
Oxford University Press
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Kaviraj, Sugata, Martin, Garreth, and Silk, Joseph. AGN in dwarf galaxies: frequency, triggering processes and the plausibility of AGN feedback. United Kingdom: N. p., 2019. Web. doi:10.1093/mnrasl/slz102.
Kaviraj, Sugata, Martin, Garreth, & Silk, Joseph. AGN in dwarf galaxies: frequency, triggering processes and the plausibility of AGN feedback. United Kingdom. doi:10.1093/mnrasl/slz102.
Kaviraj, Sugata, Martin, Garreth, and Silk, Joseph. Wed . "AGN in dwarf galaxies: frequency, triggering processes and the plausibility of AGN feedback". United Kingdom. doi:10.1093/mnrasl/slz102.
@article{osti_1557364,
title = {AGN in dwarf galaxies: frequency, triggering processes and the plausibility of AGN feedback},
author = {Kaviraj, Sugata and Martin, Garreth and Silk, Joseph},
abstractNote = {Abstract While active galactic nuclei (AGN) are considered to be key drivers of the evolution of massive galaxies, their potentially significant role in the dwarf-galaxy regime (M* < 109 M⊙) remains largely unexplored. We combine optical and infrared data, from the Hyper Suprime-Cam (HSC) and the Wide-field Infrared Explorer, respectively, to explore the properties of ∼800 AGN in dwarfs at low redshift (z < 0.3). Infrared-selected AGN fractions are ∼10–30 per cent in dwarfs, which, for reasonable duty cycles, indicates a high black hole (BH)-occupation fraction. Visual inspection of the deep HSC images indicates that the merger fraction in dwarf AGN (∼6 per cent) shows no excess compared to a control sample of non-AGN, suggesting that the AGN-triggering processes are secular in nature. Energetic arguments indicate that, in both dwarfs and massive galaxies, bolometric AGN luminosities (LAGN) are significantly greater than supernova luminosities (LSN). LAGN/LSN is, in fact, higher in dwarfs, with predictions from simulations suggesting that this ratio only increases with redshift. Together with the potentially high BH-occupation fraction, this suggests that if AGN feedback is an important driver of massive-galaxy evolution, the same is likely to be true in the dwarf regime, contrary to our classical thinking.},
doi = {10.1093/mnrasl/slz102},
journal = {Monthly Notices of the Royal Astronomical Society: Letters},
number = 1,
volume = 489,
place = {United Kingdom},
year = {2019},
month = {6}
}

Journal Article:
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