X-ray analysis of SDSS J165202.60+172852.4, an obscured quasar with outflows at peak galaxy formation epoch

Abstract

We report on deep XMM-Newton and NuSTAR observations of the high redshift, z = 2.94, extremely red quasar (ERQ), SDSS J165202.60+172852.4, with known galactic ionized outflows detected via spatially resolved [O III] emission lines. X-ray observations allow us to directly probe the accretion disc luminosity and the geometry and scale of the circumnuclear obscuration. We fit the spectra from the XMM-Newton/EPIC and NuSTAR detectors with a physically motivated torus model and constrain the source to exhibit a near Compton-thick column density of N_H = (1.02$^{+0.76}_{-0.41}$) × 10²⁴ cm^-2, a near edge-on geometry with the line-of-sight inclination angle of θ_i = 85°, and a scattering fraction of f_sc ~ 3 per cent. The absorption-corrected, intrinsic 2-10 keV X-ray luminosity of L_2-10= (1.4$^{+1}_{-1}$) × 10⁴⁵ erg s^-1 reveals a powerful quasar that is not intrinsically X-ray weak, consistent with observed trends in other ERQs. We also estimate the physical properties of the obscuration, although highly uncertain: the warm ionized scattering density of n_e ~ 7.5 × (10²-10³) cm^-3 and the obscuration mass of $M_{\rm obsc} \sim 1.7\times (10^4\!-\!10^6)\,{\rm M}_{\odot}$. As previously suggested with shallower X-ray observations, optical and infrared selection of ERQ has proved effective in finding obscured quasars with powerful outflow signatures. Our observations provide an in-depth view into the X-ray properties of ERQs and support the conclusions of severely photon-limited studies of obscured quasar populations at high redshifts.