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

TL;DR

This study uses deep X-ray observations to analyze an obscured high-redshift quasar, revealing its near Compton-thick obscuration, powerful intrinsic luminosity, and outflow properties, thereby enhancing understanding of ERQ characteristics during peak galaxy formation.

Contribution

First detailed X-ray spectral analysis of an ERQ at high redshift, constraining its obscuration geometry, column density, and intrinsic luminosity, advancing knowledge of obscured quasar populations.

Findings

Quasar exhibits near Compton-thick column density of ~10^24 cm^-2.

Intrinsic 2-10 keV luminosity indicates a powerful, not X-ray weak, quasar.

Supports optical/infrared selection effectiveness for finding obscured quasars.

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 [OIII] emission lines. X-ray observations allow us to directly probe the accretion disk 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 $N_H=(1.02^{+0.76}_{-0.41})\times10^{24}\textrm{ cm}^{-2}$, a near edge-on geometry with the line-of-sight inclination angle of $\theta_i=85^{\circ}$, and a scattering fraction of $f_{sc}\sim 3$ %. The absorption-corrected, intrinsic 2-10 keV X-ray luminosity of $L_{\textrm{2-10}}=(1.4^{+1}_{-1}) \times10^{45} \textrm{ erg s}^{-1}$ 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 $n_e \sim 7.5\times(10^2-10^3)\textrm{ cm}^{-3}$ and the obscuration mass of $M_{obsc} \sim 1.7\times(10^4-10^6) M_{\odot}$. 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.