The hyperluminous Compton-thick z similar to 2 quasar nucleus of the hot DOG W1835+4355 observed by NuSTAR

L. Zappacosta, E. Piconcelli, F. Duras, C. Vignali, R. Valiante, S. Bianchi, A. Bongiorno, F. Fiore, C. Feruglio, G. Lanzuisi, R. Maiolino, S. Mathur, G. Miniutti, C. Ricci. 2018. The hyperluminous Compton-thick z similar to 2 quasar nucleus of the hot DOG W1835+4355 observed by NuSTAR. Astronomy and Astrophysics 618, DOI: 10.1051/0004-6361/201732557

We present a 155 ksNuSTAR observation of the z similar to 2 hot dust-obscured galaxy (hot DOG) W1835+4355. We extracted spectra from the two NuSTAR detectors and analyzed them jointly with the archival XMM-Newton PN and MOS spectra. We performed a spectroscopic analysis based on both phenomenological and physically motivated models employing toroidal and spherical geometry for the obscurer. In all the modelings, the source exhibits a Compton-thick column density NH greater than or similar to 10(24) cm(-2), a 2-10 keV luminosity L2-10 approximate to 2 x 10(45) erg s(-1), and a prominent soft excess (similar to 5-10% of the primary radiative output), which translates into a luminosity similar to 10(44) erg s(-1). We modeled the spectral energy distribution from 1.6 to 850 mu m using a clumpy two-phase dusty torus model plus a modified blackbody to account for emission powered by star formation in the far-infrared. We employed several geometrical configurations consistent with those applied in the X-ray analysis. In all cases we obtained a bolometric luminosity L-bol approximate to 3-5 x 10(47) erg s(-1), which confirms the hyperluminous nature of this active galactic nucleus. Finally, we estimate a prodigious star formation rate of similar to 3000 M-circle dot yr(-1), which is consistent with the rates inferred for z approximate to 2-4 hyperluminous type I quasars. The heavily obscured nature, together with L-bol, the ratio of X-ray to mid-infrared luminosity, the rest-frame optical morphology, and the host star formation rate are indicative of its evolutionary stage. We can interpret this as a late-stage merger event in the transitional, dust-enshrouded, evolutionary phase eventually leading to an optically bright AGN.

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