The Contribution from Scattered Light to Quasar Galaxy Hosts

Abstract

We present models representing the scattering of quasar radiation off free electrons and dust grains in geometries that approximate the structure of quasar host galaxies. We show that, for reasonable assumptions, scattering alone can easily produce ratios of nuclear (point source) to extended fluxes comparable to those determined in studies of quasar hosts. This result suggests that scattered quasar light, as well as stellar emission from the host galaxy, contributes significantly to the detected extended flux, leading to uncertainty in the inferred properties of quasar host. A significant contribution from scattered quasar light will lead to overestimates of the luminosity and hence mass of the host galaxy, and may also distort its morphology. Scattering of quasar light within the host galaxy may provide alternative explanations for the apparent peak in host luminosity at z = 2-3; possibly the overall average higher luminosity of radio-loud host galaxies relative to those of radio-quiet quasars (RQQs), and the apparent preference of high-luminosity RQQs for spheroidal rather than disk galaxies.

accepted for publication in Astrophysical Journal Letters

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Cited by in corpus (9)

• The Growth of Black Holes: Insights From Obscured Active Galaxies
• Limits on Spacetime Foam
• Intermediate-Age Stellar Populations in Classical QSO Host Galaxies
• Giant scattering cones in obscured quasars
• Evidence of different star formation histories for high- and low-luminosity radio galaxies
• A Glimpse at Quasar Host Galaxy Far-UV Emission, Using DLAs as Natural Coronagraphs
• UV-Luminous, Star-Forming Hosts of z~2 Reddened Quasars in the Dark Energy Survey
• A catalog of optical to X-ray spectral energy distributions of z~2 quasars observed with Swift. I: First results
• Hubble Space Telescope Near Infrared Snapshot Survey of 3CR radio source counterparts III: Radio galaxies and quasars in context