The hidden quasar nucleus of a WISE-selected, hyperluminous,
  dust-obscured galaxy at z ~ 2.3
  We present the first X-ray spectrum of a Hot dust-obscured galaxy (DOG),
namely W1835+4355 at z ~ 2.3. Hot DOGs represent a very rare population of
hyperluminous (>= 10^47 erg/s), dust-enshrouded objects at z > 2 recently
discovered in the WISE All Sky Survey. The 40 ks XMM-Newton spectrum reveals a
continuum as flat (Gamma ~ 0.8) as typically seen in heavily obscured AGN.
This, along with the presence of strong Fe Kalpha emission, clearly suggests a
reflection-dominated spectrum due to Compton-thick absorption. In this
scenario, the observed luminosity of L(2-10 keV) ~ 2 x 10^44 erg/s is a
fraction (<10%) of the intrinsic one, which is estimated to be >~ 5 x 10^45
erg/s by using several proxies. The Herschel data allow us to constrain the SED
up to the sub-mm band, providing a reliable estimate of the quasar contribution
(~ 75%) to the IR luminosity as well as the amount of star formation (~ 2100
Msun/yr). Our results thus provide additional pieces of evidence that associate
Hot DOGs with an exceptionally dusty phase during which luminous quasars and
massive galaxies co-evolve and a very efficient and powerful AGN-driven
feedback mechanism is predicted by models.
