Properties of IR selected Active Galactic Nuclei
  Context. Active galactic nuclei (AGN) of galaxies play an important role in
the life and evolution of galaxies due to the impact they exert on certain
properties and the evolutionary path of galaxies. It is well known that
infrared (IR) emission is useful for selecting galaxies with AGNs, although it
has been observed that there is contamination by star-forming galaxies. Aims.
In this work we investigate galaxy properties hosting AGNs identified at mid
and near-IR wavelengths. The sample of AGNs selected at IR wavelengths was
confirmed using optical spectroscopy and X-ray photometry. We study the
near-UV, optical, near and mid-IR (MIR) properties, as well as [O III]
{\lambda}5007 luminosity, black hole mass and morphology properties of optical
and IR colour selected AGNs. Methods. We selected AGN candidates using two
mid-IR colour selection techniques, a power-law emission method and a
combination of mid and near-IR selection techniques. We confirm the AGN
selection with two line diagnostic diagrams that use the ratio [O III]/H\b{eta}
and the emission line width {\sigma} [O III] (kinematics-excitation diagram,
KEx) and the host galaxy stellar mass (mass-excitation diagram, 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 combination of
a mid and near-IR selection technique and a power-law emission. The method that
use a combination of mid and near-IR observation selects a large number of
AGNs, and is reasonably efficient in both the success rate (61%) and total
number of AGN recovered. We also find that the KEx method presents
contamination of SF galaxies within the AGN selection box. According to
morphological studies based on the S\'ersic index, AGN samples have higher
percentages of galaxy morphologies with bulge+disk components compared to
galaxies without AGNs.
