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.