Non linear phenomena in response models of barred-spiral disk galaxies

Doctoral Dissertation uoadl:1309171 360 Read counter

Τομέας Αστροφυσικής, Αστρονομίας και Μηχανικής
Library of the School of Science
Deposit date:
Τσιγαρίδη Ευαγγελία
Dissertation committee:
Παναγιώτης Πάτσης Δ/ντης Ερευνών (επιβλέπων), Αντώνης Πινότσης Αναπλ. Καθηγητής , Δημήτρης Φραντζεσκάκης Καθηγητής
Original Title:
Μη γραμμικά φαινόμενα σε μοντέλα απόκρισης δισκοειδών γαλαξιών
Translated title:
Non linear phenomena in response models of barred-spiral disk galaxies
We studied dynamical mechanisms that form a barred-spiral morphology by means
of response models and by investigation of the orbits that support the observed
features. Firstly, we investigated the dynamics of a barred-spiral model which
consist of an inner barred-spiral structure, surrounded by an oval-shaped disc
and a fainter set of arms at larger radii. The bar and the spiral arms inside
corotation are structured to a large extent by regular orbits, while the spiral
arms beyond corotation
are built by chaotic orbits. The vast majority of those chaotic orbits include
in their morphology the
imprints of ``4:1-resonance-like'' orbits. In the case of a barred-spiral model
when the system is
rotating slowly the bar is structured mainly by sticky orbits from regions
around the stability islands
of the central family. This leads to the appearance of X-features in the bars
on the galactic plane.
Finally, we examined the relation between stellar and gaseous flows in the
spiral arm regions of
barred-spiral potentials.Clumps of local overdensity are formed in the inner
gaseous arms as the gas
shocks in the spiral arms regions, while clumps beyond corotation are formed as
the flows along the
two arms meet close to the Lagrangian points.
Chaos, Barred-spiral galaxies, Dynamical mechanisms, Gas, Orbits
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