TY - JOUR
T1 - BAT AGN Spectroscopic Survey - III. An observed link between AGN Eddington ratio and narrow-emission-line ratios
AU - Oh, Kyuseok
AU - Schawinski, Kevin
AU - Koss, Michael
AU - Trakhtenbrot, Benny
AU - Lamperti, Isabella
AU - Ricci, Claudio
AU - Mushotzky, Richard
AU - Veilleux, Sylvain
AU - Berney, Simon
AU - Michael Crenshaw, D.
AU - Gehrels, Neil
AU - Harrison, Fiona
AU - Masetti, Nicola
AU - Soto, Kurt T.
AU - Stern, Daniel
AU - Treister, Ezequiel
AU - Ueda, Yoshihiro
N1 - Publisher Copyright:
© 2016 The Authors.
PY - 2017/1/11
Y1 - 2017/1/11
N2 - We investigate the observed relationship between black hole mass (MBH), bolometric luminosity (Lbol) and Eddington ratio (λEdd) with optical emission-line ratios ([N II] λ6583/Hα, [S II] λλ6716, 6731/Hα, [OI] λ6300/Hα, [OIII] λ5007/Hβ, [Ne III] λ3869/Hβ and He II λ4686/Hβ) of hard X-ray-selected active galactic nuclei (AGN) from the BAT AGN Spectroscopic Survey. We show that the [N II] λ6583/Hα ratio exhibits a significant correlation with λEdd (RPear = -0.44, p-value = 3 × 10-13, σ = 0.28 dex), and the correlation is not solely driven by MBH or Lbol. The observed correlation between [N II] λ6583/Hα ratio and MBH is stronger than the correlation with Lbol, but both are weaker than the λEdd correlation. This implies that the large-scale narrow lines of AGN host galaxies carry information about the accretion state of the AGN central engine. We propose that [N II] λ6583/Hα is a useful indicator of Eddington ratio with 0.6 dex of rms scatter, and that it can be used to measure λEdd and thus MBH from the measured Lbol, even for high-redshift obscured AGN.We briefly discuss possible physical mechanisms behind this correlation, such as the mass-metallicity relation, X-ray heating, and radiatively driven outflows.
AB - We investigate the observed relationship between black hole mass (MBH), bolometric luminosity (Lbol) and Eddington ratio (λEdd) with optical emission-line ratios ([N II] λ6583/Hα, [S II] λλ6716, 6731/Hα, [OI] λ6300/Hα, [OIII] λ5007/Hβ, [Ne III] λ3869/Hβ and He II λ4686/Hβ) of hard X-ray-selected active galactic nuclei (AGN) from the BAT AGN Spectroscopic Survey. We show that the [N II] λ6583/Hα ratio exhibits a significant correlation with λEdd (RPear = -0.44, p-value = 3 × 10-13, σ = 0.28 dex), and the correlation is not solely driven by MBH or Lbol. The observed correlation between [N II] λ6583/Hα ratio and MBH is stronger than the correlation with Lbol, but both are weaker than the λEdd correlation. This implies that the large-scale narrow lines of AGN host galaxies carry information about the accretion state of the AGN central engine. We propose that [N II] λ6583/Hα is a useful indicator of Eddington ratio with 0.6 dex of rms scatter, and that it can be used to measure λEdd and thus MBH from the measured Lbol, even for high-redshift obscured AGN.We briefly discuss possible physical mechanisms behind this correlation, such as the mass-metallicity relation, X-ray heating, and radiatively driven outflows.
KW - Black hole physics
KW - Galaxies: active
KW - Galaxies: nuclei
KW - Quasars: general
UR - http://www.scopus.com/inward/record.url?scp=85014644513&partnerID=8YFLogxK
U2 - 10.1093/mnras/stw2467
DO - 10.1093/mnras/stw2467
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AN - SCOPUS:85014644513
SN - 0035-8711
VL - 464
SP - 1466
EP - 1473
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -