The most-luminous heavily-obscured quasars have a high merger fraction:
  morphological study of WISE-selected hot dust-obscured galaxies
  Previous studies have shown that WISE-selected hyperluminous, hot
dust-obscured galaxies (Hot DOGs) are powered by highly dust-obscured, possibly
Compton-thick AGNs. High obscuration provides us a good chance to study the
host morphology of the most luminous AGNs directly. We analyze the host
morphology of 18 Hot DOGs at $z\sim3$ using Hubble Space Telescope/WFC3
imaging. We find that Hot DOGs have a high merger fraction ($62\pm 14 \%$). By
fitting the surface brightness profiles, we find that the distribution of
S\'ersic indices in our Hot DOG sample peaks around 2, which suggests that most
of Hot DOGs have transforming morphologies. We also derive the AGN bolometric
luminosity ($\sim10^{14}L_\odot$) of our Hot DOG sample by using IR SEDs
decomposition. The derived merger fraction and AGN bolometric luminosity
relation is well consistent with the variability-based model prediction (Hickox
et al. 2014). Both the high merger fraction in IR-luminous AGN sample and
relatively low merger fraction in UV/optical-selected, unobscured AGN sample
can be expected in the merger-driven evolutionary model. Finally, we conclude
that Hot DOGs are merger-driven and may represent a transit phase during the
evolution of massive galaxies, transforming from the dusty starburst dominated
phase to the unobscured QSO phase.
