NGC 7097: the AGN and its mirror, revealed by PCA Tomography
  Three-dimensional (3D) spectroscopy techniques are becoming more and more
popular, producing an increasing number of large data cubes. The challenge of
extracting information from these cubes requires the development of new
techniques for data processing and analysis. We apply the recently developed
technique of Principal Component Analysis (PCA) Tomography to a data cube from
the center of the elliptical galaxy NGC 7097 and show that this technique is
effective in decomposing the data into physically interpretable information. We
find that the first five principal components of our data are associated with
distinct physical characteristics. In particular, we detect a LINER with a weak
broad component in the Balmer lines. Two images of the LINER are present in our
data, one seen through a disk of gas and dust, and the other after scattering
by free electrons and/or dust particles in the ionization cone. Furthermore, we
extract the spectrum of the LINER, decontaminated from stellar and extended
nebular emission, using only the technique of PCA Tomography. We anticipate
that the scattered image has polarized light, due to its scattered nature.
