Speaker
Description
We report on a detailed study of a luminous, heavily obscured ($N_{\rm H}\sim2\times 10^{23}$ cm$^{-2}$), radio-loud quasar SRGAJ230631.0+155633, discovered by the SRG/ART-XC telescope, which is located at $z=0.4389$ and is a type 2 AGN. We combine radio-to-X-ray data, including near-simultaneous ART-XC and Swift/XRT observations conducted in June 2023. During these follow-up observations, the source was found in a significantly fainter but still very luminous state ($L_{\rm X}=1.0^{+0.8}_{-0.3}\times 10^{45}$erg s$^{-1}$, absorption corrected, 2–10keV) compared to its discovery ($L_{\rm X}=6^{+6}_{-3}\times10^{45}$ erg s$^{-1}$), indicating intrinsic variability on a rest-frame time scale of $\sim 1$ year. The radio data reveal a giant FRII radio galaxy. From multi-wavelength photometry and the black hole--bulge relation we infer a bolometric luminosity of $\sim 6\times10^{46}$ erg s$^{-1}$ and a black hole mass of $\sim1.4\times10^{9}\,M_{\odot}$, implying accretion at $\sim30$% of the Eddington limit. SRGAJ230631.0+155633 proves to be one of the most luminous obscured quasars out to $z=0.5$.
The talk will also briefly highlight several new AGN being studied by the SRG/ART-XC team.