Chemical Abundance of the LINER galaxy UGC 4805 with SDSS-IV MaNGA
  Chemical abundance determinations in Low-Ionization Nuclear Line Regions
(LINERs) are especially complex and uncertain because the nature of the
ionizing source of this kind of object is unknown. In this work, we study the
oxygen abundance in relation to the hydrogen abundance (O/H) of the gas phase
of the UGC4805 LINER nucleus. Optical spectroscopic data from the Mapping
Nearby Galaxies (MaNGA) survey was employed to derive the O/H abundance of the
UGC4805 nucleus based on the extrapolation of the disk abundance gradient, on
calibrations between O/H abundance and strong emission-lines for Active
Galactic Nuclei (AGNs) as well as on photoionization models built with the
Cloudy code, assuming gas accretion into a black hole (AGN) and post-Asymptotic
Giant Branch (p-AGB) stars with different effective temperatures. We found that
abundance gradient extrapolations, AGN calibrations, AGN and p-AGB
photoionization models produce similar O/H values for the UGC4805 nucleus and
similar ionization parameter values.
  The study demonstrated that the methods used to estimate the O/H abundance
using nuclear emission-line ratios produce reliable results, which are in
agreement with the O/H values obtained from the independent method of galactic
metallicity gradient extrapolation. Finally, the results from the WHAN diagram
combined with the fact that the high excitation level of the gas has to be
maintained at kpc scales, we suggest that the main ionizing source of the
UGC4805 nucleus probably has a stellar origin rather than an AGN.
