Exploring the differences of integrated and spatially resolved analysis
  using integral field unit data: The case of Abell 14
  We present a new approach to study planetary nebulae using integral field
spectroscopy. VLT@VIMOS datacube of the planetary nebula Abell 14 is analysed
in three different ways by extracting: (i) the integrated spectrum, (ii)
1-dimensional simulated long slit spectra for different position angles and
(iii) spaxel-by-spaxel spectra. These data are used to built emission-line
diagnostic diagrams and explore the ionization structure and excitation
mechanisms combining data from 1- and 3- dimensional photoionization models.
The integrated and 1D simulated spectra are suitable for developing diagnostic
diagrams, while the spaxel spectra can lead to misinterpretation of the
observations. We find that the emission-line ratios of Abell 14 are consistent
with UV photo-ionized emission, however there are some pieces of evidence of an
additional thermal mechanism. The chemical abundances confirm its previous
classification as a Type I planetary nebula, without spatial variation. We
find, though, variation in the ionization correction factors (ICFs) as a
function of the slit position angle. The star at the geometric centre of Abell
14 has an A5 spectral type with an effective temperature of Teff = 7909$\pm$135
K and surface gravity log(g) = 1.4$\pm$0.1 cm s$^{-2}$. Hence, this star cannot
be responsible for the ionization state of the nebula. Gaia parallaxes of this
star yield distances between 3.6 and 4.5 kpc in good agreement with the
distance derived from a 3-dimensional photoionization modelling of Abell 14,
indicating the presence of a binary system at the centre of the planetary
nebula.
