English

The relation between AGN type and host galaxy properties

Astrophysics of Galaxies 2021-02-24 v1 Cosmology and Nongalactic Astrophysics

Abstract

We use 3,213 Active Galactic Nuclei (AGNs) from the XMM\it{XMM}-XXL northern field to investigate the relation of AGN type with host galaxy properties. Applying a Bayesian method, we derive the hardness ratios (HRs) and through these the hydrogen column density (NH\rm N_H) for each source. We consider as absorbed sources (type-2) those with NH>1021.5cm2\rm N_H > 10^{21.5}\, \rm{cm^{-2}}. We examine the star formation rate (SFR) as well the stellar mass (M_*) distributions for both absorbed and unabsorbed sources. Our work indicates that there is no significant link between the AGN type and these host galaxy properties. Next, we investigate whether the AGN power, as represented by its X-ray luminosity, LX\rm L_X, correlates with any deviation of the host galaxy's place from the so-called Main Sequence of galaxies, and we examine this separately for the obscured and the unobscured AGN populations. To take into account the effect of M_* and redshift on SFR, we use the normalised SFR (SFRnorm_{norm}). We find that the correlation between LX\rm L_X and SFRnorm_{norm}, follows approximately the same trend for both absorbed and unabsorbed sources, a result that favours the standard AGN unification models. Finally, we explore the connection between the obscuration, NH\rm N_H, and the SFR. We find that there is no relation between these, suggesting that the obscuration is not related to the large scale SFR in the galaxy.

Keywords

Cite

@article{arxiv.2101.00724,
  title  = {The relation between AGN type and host galaxy properties},
  author = {V. A. Masoura and G. Mountrichas and I. Georgantopoulos and M. Plionis},
  journal= {arXiv preprint arXiv:2101.00724},
  year   = {2021}
}

Comments

A&A accepted, 11 pages, 12 Figures

R2 v1 2026-06-23T21:43:53.795Z