PROPERTIES OF IR-SELECTED ACTIVE GALACTIC NUCLEI

BORNANCINI CARLOS G.; OIO GABRIEL; ALONSO MARÍA VICTORIA; GARCÍA LAMBAS DIEGO

ASTRONOMY & ASTROPHYSICS. SUPPLEMENT SERIES (PRINT)

EDP Sciences

Lugar: Paris; Año: 2022 vol. 664

0365-0138

Context. Active galactic nuclei (AGNs) of galaxies play an important role in the life and evolution of galaxies through the impact theyexert on certain properties and on the evolutionary path of galaxies. It is well known that infrared (IR) emission is useful for selectinggalaxies with AGNs, although it has been observed that there is contamination by star-forming galaxies.Aims. We investigate the properties of galaxies that host AGNs that are identified at mid- (MIR) and near-IR wavelengths. The sampleof AGNs selected at IR wavelengths was confirmed using optical spectroscopy and X-ray photometry. We study the near-UV, optical,near-IR and MIR properties, as well as the [O iii ] λ5007 luminosity, black hole mass, and morphology properties of optical and IRcolour-selected AGNs.Methods. We selected AGN candidates using two MIR colour selection techniques: a power-law emission method, and a combina-tion of MIR and near-IR selection techniques. We confirmed the AGN selection with two line diagnostic diagrams that use the ratio[O iii ]/Hβ and the emission line width σ [O iii ] (kinematics–excitation diagram, KEx) and the host galaxy stellar mass (mass–excitationdiagram, MEx), as well as X-ray photometry.Results. According to the diagnostic diagrams, the methods with the greatest success in selecting AGNs are those that use a combi-nation of a mid- and near-IR selection technique and a power-law emission. The method that uses a combination of MIR and near-IRobservations selects a large number of AGNs and is reasonably efficient in the success rate (61%) and total number of AGNs recov-ered. We also find that the KEx method presents contamination of star-forming galaxies within the AGN selection box. Accordingto morphological studies based on the Sérsic index, AGN samples have higher percentages of galaxy morphologies with bulge+diskcomponents than galaxies without AGNs