Comparative analysis of the SFR of AGN and non-AGN galaxies, as a function of stellar mass, AGN power, cosmic time and obscuration

Abstract

This study involves a comparative analysis of the SFRs of AGN and non-AGN galaxies and of the SFRs of type 1 and 2 AGN. To carry out this investigation, we assembled a dataset consisting of 2\,677 X-ray AGN detected by the XMM-Newton observatory and a control sample of 64\,556 galaxies devoid of AGN. We generated SEDs for these objects using photometric data from the DES, VHS, and AllWISE surveys, and we harnessed the CIGALE code to extract measurements for the (host) galaxy properties. Our dataset encompasses sources spanning a range from $\rm 9.5<\log\,[M_*(M_\odot)]<12.0$, $\rm 42<\log\,[L_{X,2-10keV}(ergs^{-1})]<45.5$, and $\rm 0.3<z<2.5$. To compare SFRs, we calculated the SFR$_{norm}$ parameter. Our analysis revealed that AGN tend to exhibit elevated SFRs compared to non-AGN galaxies, particularly beyond a certain threshold in L$_X$. Notably, this threshold increases as we move towards more massive galaxies. Additionally, for AGN systems with the same L$_X$, the magnitude of the SFR$_{norm}$ decreases as we consider more massive galaxies. This suggests that in galaxies with AGN, the increase in SFR as a function of M$_*$ is not as prominent as in galaxies without AGN. This interpretation finds support in the shallower slope we identify in the X-ray star-forming MS in contrast to the galaxy MS. Employing CIGALE's measurements, we classified AGN into type 1 and type 2. In our investigation, we focused on a subset of 652 type 1 AGN and 293 type 2 AGN with $\rm 10.5<\log,[M_(M_\odot)]<11.5$. Based on our results, type 1 AGN display higher SFRs than type 2 AGN, at redshifts below $\rm z<1$. However, at higher redshifts, the SFRs of the two AGN populations tend to be similar. At redshifts $\rm z<1$, type 1 AGN show augmented SFRs in comparison to non-AGN galaxies. In contrast, type 2 AGN exhibit lower SFRs when compared to galaxies that do not host an AGN.