2025ApJ...978..164Y

The outshining light from active galactic nuclei (AGNs) poses significant challenges in studying the properties of AGN host galaxies. To address this issue, we propose a novel approach that combines image decomposition and spectral energy distribution (SED) decomposition to constrain the properties of AGN host galaxies. Image decomposition allows us to disentangle optical flux into AGN and stellar components, thereby providing additional constraints on the SED models to derive a more refined stellar mass. To test the viability of this approach, we obtained a sample of 24 X-ray-selected type I AGNs with redshifts ranging from 0.73 to 2.47. We estimated the stellar masses for our sample and found that our results are generally consistent with earlier estimates based on different methods. Through examining the posterior distribution of stellar masses, we find that our method could derive better-constrained results compared to previous SED decomposition methods. With the derived stellar masses, we further studied the M_BH-M_⋆ relation of our sample, finding a higher intrinsic scatter in the correlation for our entire sample compared to the local quiescent correlation, which could be caused by a few “black hole monsters” in our sample. We propose that, based on our method, future works could extend to larger samples of high-redshift AGN host galaxies, thereby enhancing our understanding of their properties.