Low-luminosity AGN and X-Ray Binary Populations in COSMOS Star-forming Galaxies

Francesca M. Fornasini, Francesca Civano, Giuseppina Fabbiano, Martin Elvis, Stefano Marchesi, Takamitsu Miyaji, Andreas Zezas
2018 Astrophysical Journal  
We present an X-ray stacking analysis of ∼75,000 star-forming galaxies between 0.11.3 exhibit a significant X-ray excess indicating nuclear emission. The AGN emission is strongly correlated with stellar mass but does not exhibit an additional correlation with SFR. The hardness ratios of the high-redshift stacks indicate that the AGN are substantially obscured (N_H∼10^23 cm^-2). These obscured AGN are not identified by IRAC color selection and have L_X∼10^41-10^43 erg s^-1, consistent with
more » ... ion at an Eddington rate of ∼10^-3 onto 10^7-10^8 M_ black holes. Combining our results with other X-ray studies suggests that AGN obscuration depends on stellar mass and an additional variable, possibly the Eddington rate.
doi:10.3847/1538-4357/aada4e fatcat:nt5qgyomhnalvciolzmlpmosoy