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-1), 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 (Γ~0.8) as typically seen in heavily obscured AGN. This, along with the presence of strong Fe Kα emission, clearly suggests a reflection-dominated spectrum due to Compton-thick absorption. In this scenario, the observed luminosity of L2-10 ∼ 2 × 10^44 erg s-1 is a fraction (<10%) of the intrinsic one, which is estimated to be ≳ 5 × 10^45 erg s-1 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 M⊙ yr-1). 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.

The hidden quasar nucleus of a WISE-selected, hyperluminous, dust-obscured galaxy at z~2.3

VIGNALI, CRISTIAN;LANZUISI, GIORGIO;
2015

Abstract

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-1), 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 (Γ~0.8) as typically seen in heavily obscured AGN. This, along with the presence of strong Fe Kα emission, clearly suggests a reflection-dominated spectrum due to Compton-thick absorption. In this scenario, the observed luminosity of L2-10 ∼ 2 × 10^44 erg s-1 is a fraction (<10%) of the intrinsic one, which is estimated to be ≳ 5 × 10^45 erg s-1 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 M⊙ yr-1). 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.
2015
Piconcelli E.; Vignali C.; Bianchi S.; Zappacosta L.; Fritz J.; Lanzuisi G.; Miniutti G.; Bongiorno A.; Feruglio C.; Fiore F.; Maiolino R.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/503374
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