On the relation of host properties and environment of AGN galaxies across the standard optical diagnostic diagram

Abstract

We study the host properties and environment of active galactic nuclei (AGNs) galaxies, taken from SDSS-DR12, across the $\text{[O III]}/\text{H}\beta$ vs $\text{[N II]}/\text{H}\alpha$ diagnostic diagram. We select AGN subsamples defined as parallel and perpendicular to the star-forming locus on the BPT diagram based on the Kauffmann et al. and Schawinski et al. criteria. For parallel subsamples we find that AGN host properties exhibit a morphological evolution as they become more distant to the star-forming sequence. The local density environment shows a more evident morphology-density relationship for subsamples mainly formed by Composite and Spiral galaxies than those containing LINERs and Seyferts, where the AGN emission is the dominant source. We also analyse the properties of the five closest AGN neighbours observing no significant differences in the environment, although the AGN host properties of every subsample have noticeable variations. The AGNs belonging to perpendicular subsamples show clear differences on their host properties from left top to right bottom on the diagram. However, the analysis of the local density environment do not reflect strong dependency with the host AGN properties. This result is reinforced by the characteristics of the AGN neighbouring galaxies. These findings suggest that mixed AGN/star-forming galaxies present environmental features more similar to that of non-active galaxies. However, as AGNs at the centre of the more evolved galaxies become the dominant source, the environment tends to provide suitable conditions for the central black hole feeding with an increasing content of gas and likelihood of a higher merger rate.

References in corpus (15)

• The Host Galaxies and Classification of Active Galactic Nuclei
• UV Star Formation Rates in the Local Universe
• Galaxy Zoo 1 : Data Release of Morphological Classifications for nearly 900,000 galaxies
• Galaxy Zoo: the dependence of morphology and colour on environment
• AGN Emission Line Diagnostics and the Mass-Metallicity Relation up to Redshift z~2: the Impact of Selection Effects and Evolution
• AGNs and galaxy interactions
• The AGN fraction - velocity dispersion relation in clusters of galaxies
• From blue star-forming to red passive: galaxies in transition in different environments
• Properties of galaxies in SDSS Quasar environments at z < 0.2
• Exploring galaxy colour in different environments of the cosmic web with SDSS
• Groups of galaxies: relationship between environment and galaxy properties
• The X-ray View of Merger-Induced AGN Activity at Low Redshift
• Role of environment on nuclear activity
• Occurrence of LINER galaxies within the galaxy group environment
• AGN and Star-Formation Properties of Inside-out Assembled Galaxy Candidates at z<0.1

Cited by in corpus (1)

• AGN with massive black holes have closer galactic neighbors: k-Nearest-Neighbor statistics of an unbiased sample of AGN at z~0.03