[O iii] 5007 Å Emission Line Width as a Surrogate for σ _∗ in Type 1 AGNs?

Abstract

Abstract We present a study of the relation between the [O iii ] 5007 Å emission line width ( σ [O III ] ) and stellar velocity dispersion ( σ * ), utilizing a sample of 740 type 1 active galactic nuclei (AGNs) with high-quality spectra at redshift z &lt; 1.0. We find the broad correlation between the core component of the [O iii ] emission line width ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mo stretchy="false">[</mml:mo> <mml:mi mathvariant="normal">O</mml:mi> <mml:mi mathsize="small" mathvariant="normal">III</mml:mi> <mml:mo>,</mml:mo> <mml:mi>core</mml:mi> <mml:mo stretchy="false">]</mml:mo> </mml:mrow> </mml:msub> </mml:math> ) and σ * with a scatter of 0.11 dex for the low redshift ( z &lt; 0.1) sample; for redshift (0.3 &lt; z &lt; 1.0) AGNs, the scatter is larger, being 0.16 dex. We also find that the Eddington ratio ( L bol / L Edd ) may play an important role in the discrepancies between <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mo stretchy="false">[</mml:mo> <mml:mi mathvariant="normal">O</mml:mi> <mml:mi mathsize="small" mathvariant="normal">III</mml:mi> <mml:mo>,</mml:mo> <mml:mi>core</mml:mi> <mml:mo stretchy="false">]</mml:mo> </mml:mrow> </mml:msub> </mml:math> and σ * . As the L bol / L Edd increases, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mo stretchy="false">[</mml:mo> <mml:mi mathvariant="normal">O</mml:mi> <mml:mi mathsize="small" mathvariant="normal">III</mml:mi> <mml:mo>,</mml:mo> <mml:mi>core</mml:mi> <mml:mo stretchy="false">]</mml:mo> </mml:mrow> </mml:msub> </mml:math> tends to be larger than σ * . By classifying our local sample with different minor-to-major axis ratios, we find that σ * is larger than <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mo stretchy="false">[</mml:mo> <mml:mi mathvariant="normal">O</mml:mi> <mml:mi mathsize="small" mathvariant="normal">III</mml:mi> <mml:mo>,</mml:mo> <mml:mi>core</mml:mi> <mml:mo stretchy="false">]</mml:mo> </mml:mrow> </mml:msub> </mml:math> for those edge-on spiral galaxies. In addition, we also find that the effects of outflow strength properties such as maximum outflow velocity ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>V</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>max</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) and the broader component of the [O iii ] emission line width and line shift ( σ [O III ,out] and V [O III ,out] ) may play a major role in the discrepancies between <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mo stretchy="false">[</mml:mo> <mml:mi mathvariant="normal">O</mml:mi> <mml:mi mathsize="small" mathvariant="normal">III</mml:mi> <mml:mo>,</mml:mo> <mml:mi>core</mml:mi> <mml:mo stretchy="false">]</mml:mo> </mml:mrow> </mml:msub> </mml:math> and σ * . The discrepancies between <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mo stretchy="false">[</mml:mo> <mml:mi mathvariant="normal">O</mml:mi> <mml:mi mathsize="small" mathvariant="normal">III</mml:mi> <mml:mo>,</mml:mo> <mml:mi>core</mml:mi> <mml:mo stretchy="false">]</mml:mo> </mml:mrow> </mml:msub> </mml:math> and σ * are larger when <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>V</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>max</mml:mi> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjacb770ieqn8.gif" xlin

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