Seimei KOOLS-IFU Mapping of the Gas and Dust Distributions in Galactic
  Planetary Nebulae: the Case of IC2165
  We investigated the physical and chemical properties of the gas and dust
components in a carbon-rich planetary nebula (PN) IC2165 using two-dimensional
(2-D) emission-line maps with superior resolution. The extinction map is
generated in a self-consistent and assumption-free manner. The circumstellar
gas-to-dust mass ratio (GDR) map ranges radially from 1210 in the central
nebula filled with hot gas plasma to 120 near the ionisation front. The
determined GDR is comparable to ~400, which is commonly adopted for carbon-rich
asymptotic giant branch (AGB) stars, and ~100 for ISM. Except for the inner
regions, the GDR in IC2165 is nearly the same as in such AGB stars, indicating
that most dust grains withstand the harsh radiation field without being
destroyed. The gas and dust mass distributions concentrated in the equatorial
plane may be related to the nonisotropic mass loss during the AGB phase and
nebula shaping. The spatial distributions of electron densities/temperatures
and ionic/elemental abundances were investigated herein. We determined 13
elemental abundances using PSF-matched spatially integrated multiwavelength
spectra extracted from the same aperture. Their values are consistent with
values predicted by a theoretical model for stars of initially 1.75 Msun and Z
= 0.003. Finally, we constructed the photoionisation model using our distance
measurement to be consistent with all derived quantities, including the GDR and
gas and dust masses and post-AGB evolution. Thus, we demonstrate the capability
of Seimei/KOOLS-IFU and how the spatial variation of the gas and dust
components in PNe derived from IFU observations can help understand the
evolution of the circumstellar/interstellar medium.
