Methods to determine water vapour sorption on mass standards

A Picard, H Fang
2004 Metrologia  
The location of warm dust producing the mid-infrared (MIR) emission in type 1 active galactic nuclei (AGNs) is complex and not yet fully known. We explore this problem by studying how the MIR covering factor (CF MIR = L MIR /L bol ) correlates with the fundamental parameters of AGN accretion process (such as L bol , black hole mass M BH , and Eddington ratio L/L Edd ) and the properties of narrow emission lines (as represented by [O iii] λ5007), using large data sets derived from the Sloan
more » ... from the Sloan Digital Sky Spectroscopic Survey (SDSS) and the Wide Infrared Sky Survey (WISE). First, we find that the luminosity of the [O iii] wing component (L wing ) correlates more tightly with the continuum luminosity (λL λ (5100)) than the luminosity of the line core component (L core ) does, which is in line with our previous conclusion that the wing component, generally blueshifted, originates from the polar outflows in the inner narrow-line region (NLR). We then find that the MIR CF shows the strongest correlation with L wing /L bol rather than with L core /L bol or the above fundamental AGN parameters, and the correlation becomes stronger as the infrared wavelength increases. We also confirm the anti-correlations of CF MIR with L bol and M BH , and the lack of dependence of CF MIR on the Eddington ratio. These results suggest that a large fraction of the warm dust producing MIR emission in AGNs is likely embedded in polar outflows in the NLR instead of in the torus.
doi:10.1088/0026-1394/41/4/016 fatcat:ar3kkyhgmre7zko3owxpufaxi4