Oral Presentation

eROSITA view of WISE-selected AGN at z ≤ 4

Author(s): Yoshiki Toba (Kyoto U.) Teng Liu (MPE), Tanya Urrutia (AIP), Mara Salvato (MPE), Junyao Li (USTC), Yoshihiro Ueda (Kyoto U.), Marcella Brusa (U. of Bologna), Naomichi Yutani (Kagoshima U.), Keiichi Wada (Kagoshima U.), and HSC-eROSITA AGN collaboration

Presenter: Yoshiki Toba (Kyoto University)

We present the physical properties of mid-IR (MIR) galaxies/AGN at z ≤ 4 in the 140 deg^2 field observed by SRG/eROSITA using the PV phase program (eFEDS). By cross-matching the WISE 22 µm (W4)-detected sample and the eFEDS X-ray point-source catalog, we find that 692 extragalactic objects are detected by eROSITA. We have compiled a multi-wavelength dataset extending from X-ray to far-IR wavelengths. We have also performed (i) an X-ray spectral analysis, (ii) SED fitting using X-CIGALE, (iii) 2D image-decomposition analysis using Subaru Hyper Suprime-Cam (HSC) images, and (iv) optical spectral fitting with QSFit to investigate the AGN and host-galaxy properties. For 7,088 WISE 22 µm objects that are undetected by eROSITA, we have performed an X-ray stacking analysis to examine the typical physical properties of these X-ray faint and/or probably obscured objects. We find that (i) 82% of the eFEDS-W4 sources are classified as X-ray AGN with log LX ≥ 42 erg/s, (ii) 67% and 24% of the objects have log (LIR/Lsun) ≥ 12 and 13, respectively, (iii) the relationship between LX and the 6 µm luminosity is consistent with that reported in previous works, and (iv) the relationship between the Eddington ratio and NH for the eFEDS–W4 sample and a comparison with a model prediction from a galaxy-merger simulation indicates that approximately 5% of the eFEDS–W4 sources in our sample are likely to be in an AGN-feedback phase, in which strong radiation pressure from the AGN blows out the surrounding material from the nuclear region (Toba et al. 2022, Astronomy and Astrophysics, in press.).