We have observed the central region of the nearby starburst galaxy NGC 253
with the Kyoto Tridimensional Spectrograph II (Kyoto3DII) Fabry-Perot mode
in order to investigate the properties of its galactic wind.
Since this galaxy has a large inclination, it is easy to observe its
galactic wind.
We produced the Ha, [N II]6583, and [S II]6716,6731 images, as well as
those line ratio maps.
The [N II]/Ha ratio in the galactic wind region is larger than those in
H II regions in the galactic disk.
The [N II]/Ha ratio in the southeastern filament, a part of the galactic
wind, is the largest and reaches about 1.5.
These large [N II]/Ha ratios are explained by shock ionization/excitation.
Using the [N II]/Ha ratio map, we spatially separate the galactic wind
region from the starburst region.
The kinetic energy of the galactic wind can be sufficiently supplied by
supernovae in a starburst region in the galactic center.
The shape of the galactic wind and the line ratio maps are non-axisymmetric
about the galactic minor axis, which is also seen in M82.
In the [N II]6583/[S II]6716,6731 map, the positions with large ratios
coincide with the positions of star clusters found in the Hubble Space
Telescope (HST) observation.
This means that intense star formation causes strong nitrogen enrichment in
these regions. Our unique combination of Ha, [N II], and [S II] line ratio
maps has demonstrated its effectiveness for clearly distinguishing between
shocked gas regions and starburst regions, determining the extent of
galactic wind as well as its mass and kinetic energy, and discovering
regions with enhanced nitrogen abundance.