2012/11/04 by Daniel Weedman, Lusine Sargsyan, Vianney Lebouteiller +2 · 2 citations
Physics and Astronomy · #Active galactic nucleus #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Infrared #Infrared telescope #Luminosity #Luminous infrared galaxy #Photometry (optics) #Quasar #Sky #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/761/2/184
accepted for publication in The Astrophysical Journal
arxiv created 2012/11/04 · openalex publication_date 2012/12/06 · arxiv updated 2015/06/12 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
Mid-infrared spectroscopic measurements from the Infrared Spectrometer (IRS) on Spitzer are given for 125 hard X-ray active galactic nuclei (AGNs; 14–195 keV) from the Swift Burst Alert Telescope (BAT) sample and for 32 AGNs with black hole masses (BHMs) from reverberation mapping. The 9.7 μm silicate feature in emission or absorption defines an infrared AGN classification describing whether AGNs are observed through dust clouds, indicating that 55% of the BAT AGNs are observed through dust. The mid-infrared dust continuum luminosity is shown to be an excellent indicator of intrinsic AGN luminosity, scaling closely with the hard X-ray luminosity, log ν L ν (7.8 μm)/ L (X) = −0.31 ± 0.35, and independent of classification determined from silicate emission or absorption. Dust luminosity scales closely with BHM, log ν L ν (7.8 μm) = (37.2 ± 0.5) + 0.87 log BHM for luminosity in erg s −1 and BHM in M ☉ . The 100 most luminous type 1 quasars as measured in ν L ν (7.8 μm) are found by comparing Sloan Digital Sky Survey (SDSS) optically discovered quasars with photometry at 22 μm from the Wide-Field Infrared Survey Explorer ( WISE ), scaled to rest frame 7.8 μm using an empirical template determined from IRS spectra. The most luminous SDSS/ WISE quasars have the same maximum infrared luminosities for all 1.5 < z < 5, reaching total infrared luminosity L IR = 10 14.4 L ☉ . Comparing with dust-obscured galaxies from Spitzer and WISE surveys, we find no evidence of hyperluminous obscured quasars whose maximum infrared luminosities exceed the maximum infrared luminosities of optically discovered quasars. Bolometric luminosities L bol estimated from rest-frame optical or ultraviolet luminosities are compared to L IR . For the local AGN, the median log L IR / L bol = −0.35, consistent with a covering factor of 45% for the absorbing dust clouds. For the SDSS/ WISE quasars, the median log L IR / L bol = 0.1, with extremes indicating that ultraviolet-derived L bol can be seriously underestimated even for type 1 quasars.