UV brightness of each of the quasar host galaxies. This significantly increases the sample of high-redshift quasar hosts with deep UV upper limits determined by this method, extending on the previous work of @Mechtley2012 which studied only one quasar. The subtraction of the quasar PSF using the software also allows for an unobscured view of the quasar environment on kpc-scales, uncovering nearby galaxies which may be interacting with the host and triggering this rapid black hole growth.

Throughout this paper we adopt a $\Lambda{}$CDM cosmology with $H_{0}=67$ km s Mpc, $\Omega{}_{M} = 0.3$, and $\Omega{}_{\Lambda{}} = 0.7$ [@Planck2014]. All magnitudes are on the AB system [@oke_1983] and have been corrected for Galactic extinction using the reddening map of @schlegel_1998 as recalibrated by @Schlafly2011.

Quasar Sample
=============

In this work we study five UV-faint FIR-luminous quasars and one dust-free quasar, all at $z\simeq6$. The dust-free quasar was observed in a second epoch of the original pilot program, alongside SDSS J1148+5251 [ID 12332, PI: R. Windhorst; see @Mechtley2012], but is previously unpublished. The five UV-faint FIR-luminous quasars were observed in 2013 as part of HST program 12974 (PI: M. Mechtley), which built on the original program. The observations and modeling technique (§ 