The host galaxies and classification of active galactic nuclei

By Lisa J. Kewley, B. Groves, G. Kauffmann, Tim Heckman U. Hawaii, M. F. Astrophysik, J. University. 2006

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We present an analysis of the host properties of 85224 emission-line galaxies selected from the Sloan Digital Sky Survey. We show that Seyferts and LINERs form clearly separated branches on the standard optical diagnostic diagrams. We derive a new empirical classification scheme which cleanly separates star-forming galaxies, composite AGN-H ii galaxies, Seyferts and LINERs and we study the host galaxy properties of these different classes of objects. LINERs are older, more massive, less dusty and more concentrated, and they and have higher velocity dispersions and lower [OIII] luminosities than Seyfert galaxies. Seyferts and LINERs are most strongly distinguished by their [OIII] luminosities. We then consider the quantity L[OIII]/σ 4 , which is an indicator of the black hole accretion rate relative to the Eddington rate. Remarkably, we find that at fixed L[OIII]/σ 4 , all differences between Seyfert and LINER host properties disappear. LINERs and Seyferts form a continuous sequence, with LINERs dominant at low L/LEDD and Seyferts dominant at high L/LEDD . These results suggest that the majority of LINERs are AGN and that the Seyfert/LINER dichotomy is analogous to the high/low-state transition for X-ray binary systems. We apply theoretical photo-ionization models and show that pure LINERs require a harder ionizing radiation field with lower ionization parameter than Seyfert galaxies, consistent with the low and high X-ray binary states.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/87929df561524051f18e252cc8112c6c3db8ddb9

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Citations in the corpus

High luminosity, slow ejecta and persistent carbon lines: SN 2009dc challenges thermonuclear explosion scenarios (2010, positive): “Though weak emission lines are detected, their flux ratios indicate ionization by an active galactic nucleus according to the BPT (Baldwin, Phillips & Terlevich 1981) diagram boundaries defined by Kewley et al. (2006).”
A comprehensive classification of galaxies in the SDSS: How to tell true from fake AGN? (2010, methodology): “Similarly, the division atWHα = 6 Å represents an optimal transposition of the Kewley et al.(2006) division between Seyferts and LINERs on the basis of 7 emission lines.”
Eliminating error in the chemical abundance scale for extragalactic H ii regions (2012, methodology): “…similar to those produced by Dopita et al. (2000), and subsequently used by Kewley & Dopita (2002), but the chemical abundances have been specifically modified so as to provide a better fit to the Sloan Digital Sky Survey (SDSS) observed sequence of extragalactic H ii regions (Kewley et al. 2006).”
METALLICITY GRADIENTS AND GAS FLOWS IN GALAXY PAIRS (2010, methodology): “Our pairs were selected to (a) span a range of positions on the luminositymetallicity relation in Kewley et al. (2006a), (b) contain at least one galaxy with suitable orientation for metallicity gradient analysis, and (c) to span a range of galaxy properties that may influence metallicity gradients…”
CONFIRMATION OF A STAR FORMATION BIAS IN TYPE Ia SUPERNOVA DISTANCES AND ITS EFFECT ON THE MEASUREMENT OF THE HUBBLE CONSTANT (2014, background): “The SDSS spectrum of the core reveals evidence for LINER activity, with stellar-absorption-corrected Hα emission significantly weaker than [N ii] λ6583 Å or [S ii] λ6717, 6731 Å (Baldwin et al. 1981; Veilleux & Osterbrock 1987; Kewley et al. 2006).”
The properties of the star-forming interstellar medium at z = 0.84-2.23 from HiZELS : mapping the internal dynamics and metallicity gradients in high-redshift disc galaxies. (2012, background): “We caution that the [N II]/Hα ratio is sensitive to shock excitation, the ionization state of the gas, and the hard ionization radiation field from an AGN (Kewley & Dopita 2002; Kewley et al. 2006; Rich et al. 2010).”
Galaxy Zoo: a sample of blue early-type galaxies at low redshift (2009, methodology): “We use the main emission lines ([OIII]λ5007, Hβ, Hα, [NII] λ6583, [SII] λ6583, [OI] λ6583) measured from such processed spectra on diagnostic diagrams (Kauffmann et al. 2003; Miller et al. 2003; Kewley et al. 2001, 2006).”
DWARF GALAXIES WITH OPTICAL SIGNATURES OF ACTIVE MASSIVE BLACK HOLES (2013, background): “In this diagram, line-emitting galaxies separate into a V -shape (e.g., Kewley et al. 2006; Groves et al. 2006).”
OPTICAL SPECTROSCOPY AND NEBULAR OXYGEN ABUNDANCES OF THE SPITZER/SINGS GALAXIES (2010, methodology): “…we classify the SINGS galaxies into three broad categories: AGNs, star-forming (SF) galaxies, and composite systems, or SF/AGN, as defined below; further separating the AGN into Seyferts (Seyfert 1943) and LINERs (Heckman 1980; Kewley et al. 2006; Ho 2008) is beyond the scope of this paper.”
BAT AGN Spectroscopic Survey. I. Spectral Measurements, Derived Quantities, and AGN Demographics (2017, methodology): “Emission Line Classification We use the emission line diagnostics of Veilleux & Osterbrock (1987), revised by Kewley et al. (2006).”
Galaxy pairs in the Sloan Digital Sky Survey – VIII. The observational properties of post-merger galaxies (2013, methodology): “We can then apply the LINER diagnostic of Kewley et al. (2006), allowing us to construct a sample of Seyfert-dominated spectra.”
GALAXY-WIDE SHOCKS IN LATE-MERGER STAGE LUMINOUS INFRARED GALAXIES (2011, methodology): “Contribution from a Seyfert AGN pushes points into the upper region of the diagrams while more LINER-like emission lies to the right hand side of the diagrams, as shown by the dividing line in the [SII] and [OI] diagnostics, as established in Kewley et al. (2006).”
PRIMUS: THE DEPENDENCE OF AGN ACCRETION ON HOST STELLAR MASS AND COLOR (2011, background): “…surveys to identify AGNs from their optical line-emission, in particular the Sloan Digital Sky Survey (SDSS; e.g., Kauffmann et al. 2003a; Heckman et al. 2004; Kauffmann et al. 2004; Hao et al. 2005; Kewley et al. 2006; Schawinski et al. 2007, although see also Georgakakis & Nandra 2011).”
SDSS-IV MaNGA : the impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements (2016, methodology): “On the classical BPT diagram (Baldwin et al. 1981; Veilleux & Osterbrock 1987; Kewley et al. 2001, 2006; Kauffmann et al. 2003), the location of an H ii region is mainly determined by its metallicity and ionization parameter (e.g., Kewley et al. 2002; Dopita et al. 2013).”
Energetic galaxy-wide outflows in high-redshift ultraluminous infrared galaxies hosting AGN activity (2012, background): “5; Table 4) has a high [OIII ]/Hβ >4.0 line ratio, which along with the high [NII ]/Hα=0.8±0.1 line ratio (Alaghband-Zadeh et al. 2012) suggests AGN activity (e.g., Kewley et al. 2006).”
What drives the growth of black holes (2011, background): “…in the local Universe, with ≈ 5–10% of nearby galaxies found to clearly host optical AGN activity (i.e., identified as Seyfert galaxies from their optical emission-line properties; e.g., Veilleux & Osterbrock 1987; Kewley et al. 2001, 2006; Maiolino & Rieke 1995; Ho et al. 1997a; Hao et al. 2005.”
Galaxy Zoo Green Peas: discovery of a class of compact extremely star-forming galaxies (2009, methodology): “We use a classical emission line diagnostic originally devis d by Baldwin, Phillips & Terlevich 1981 (hereafter BPT) and modified by others (Osterbrock & Pogge 1985; Veilleux & Osterbrock 1987; Kewley et al. 2001, 2006; Kauffmann et al. 2003) to classify the narrow line objects.”
Minor Galaxy Interactions: Star Formation Rates and Galaxy Properties (2007, neutral): “7Y9), according to the definitions in Kewley et al. (2006).”