The properties of supermassive black holes and their host galaxies for type 1 and 2 AGN in the eFEDS and COSMOS fields

Abstract

In this study, our primary objective is to compare the properties of SMBH and their host galaxies between type 1 and type 2 AGN. In our analysis, we use X-ray detected sources in two fields, namely the eFEDS and the COSMOS-Legacy. To classify the X-ray sources, we perform SED fitting analysis, using the CIGALE code. Ensuring the robustness of our analysis is paramount, and to achieve this, we impose stringent selection criteria. Thus, only sources with extensive photometric data across the optical, near- and mid-infrared part of the spectrum and reliable host galaxy properties and classifications were included. The final sample consists of 3,312 AGN, of which 3\,049 are classified as type 1 and 263 as type 2. The sources span a redshift range of $\rm 0.5<z<3.5$ and encompass a wide range of L$_X$, falling within $\rm 42<log,[L_{X,2-10keV}(ergs^{-1})]<46$. Our results show that type 2 AGN exhibit a tendency to inhabit more massive galaxies, by $0.2-0.3$\,dex, compared to type 1 sources. Type 2 AGN also display, on average, lower specific black hole accretion rates, a proxy of the Eddington ratio, compared to type 1 AGN. These differences persist across all redshifts and L$_X$ considered within our dataset. Moreover, our analysis uncovers, that type 2 sources tend to have lower star-formation rates compared to 1 AGN, at $\rm z<1$. This picture reverses at $\rm z>2$ and $\rm log,[L_{X,2-10keV}(ergs^{-1})]>44$. Similar patterns emerge when we categorize AGN based on their X-ray obscuration levels ($N_H$). However, in this case, the observed differences are pronounced only for low-to-intermediate L$_X$ AGN and are also sensitive to the $\rm N_H$ threshold applied for the AGN classification. These comprehensive findings enhance our understanding of the intricate relationships governing AGN types and their host galaxy properties across diverse cosmic epochs and luminosity regimes.