Mashchenko S. Ya. Three-dimensional models of the galactic
supershells. Candidate of Sciences (Physics and Mathematics) in 01.03.02
-- Astrophysics and Radioastronomy, a manuscript. Main Astronomical
Observatory of the National Academy of Sciences of Ukraine, Kyiv, 1996.
Five papers on simulating the three-dimensional expanding HI supershells
and comparing the results obtained with observational data are defended.
Numerical 3D hydrodynamic scheme based on thin layer approximation to
simulate the superbubble evolution has been adopted for different
galactic environments. From the results of simulations it has been shown
that Milky Way supershells can form massive molecular clouds at the late
stages of evolution. Such clouds can be formed only in the superbubbles
with galactocentric radii 
kpc and if the distance of parental
OB-association to the plane of Galaxy is 
pc. Thus, the supershells
can be an efficient mechanism for transferring the interstellar atomic
hydrogen to molecular form.
New method to remove the uncertainty in the galactic angular momentum
determination has been obtained. It is based on comparison of elongation
directions of the observed holes in HI distribution with the results of 3D
supershell evolution simulations. It has been confirmed that the M31 galaxy
spin is directed to observer, and has been shown that the HoII galaxy spin
is directed outwards.
A procedure allowing to project the results of 3D supershell simulations on
the plane of view in different velocity channels has been introduced. It
takes into account a widening of the 21 cm spectral line due to chaotic
motions in the ISM, and radiotelescope beam smoothing. For a few
supershells in the M31 and HoII model galaxies the criteria usually used
for compiling the HI deficit regions lists have been analyzed. It has been
shown that three of these criteria -- presence of hole in at least three
successive velocity channels, stationarity of the hole center and good
contrast of the hole to its surroundings in all the relevant channel maps
-- describe very well supershells located near the galactic line of nodes,
and much worse -- the ones being far away from this line.