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Monday 20 April 2015 (12:00)

A major effect of Cosmic Rays on the ISM discovered: implications for tracing H2 gas in the Universe.

Padelis Papadopoulos
ESO visitor scientist, Ernest Rutherford Fellow (University of Cardiff), Assistant Professor, University of Thessaloniki


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Tsigaridi, L. and Patsis, P.A., 2015, MNRAS (in press), Morphologies introduced by bistability in barred-spiral galactic potentials

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Sticky Orbits and Boxy Structures in Galaxies

A significant role for the morphology of 3D bars play the chaotic orbits that are found to be sticky to the rotational tori (Vrahatis et al. 1997) around the stable periodic orbits belonging to the families x1v1 and x1v1' (Skokos et al. 2002). These families are introduced in the system at the vertical 2:1 resonance and are considered as the backbone of the boxy/peanut (b/p) bulges observed in edge-on disk galaxies. The sticky chaotic orbits support simultaneously the b/p morphology in edge-on views and boxy features in face-on views. The figure at the top (a) summarizes the contribution of all significant orbits in a 3D Ferrers bar model that participate in enhancing b/p bilges at a characteristic energy (Patsis & Katsanikas 2014a). It gives the (z,pz) projection of the 4D phase space of x1 orbits perturbed in the pz direction, at Ej=-0.41. We indicate with black and grey "*" symbols the location of the x1v1 and x1v1' periodic orbits respectively. Red and green "x" symbols indicate the two branches of x1v2 (Skokos et al. 2002). The "▲" at (z,pz=(0.1,0.42) marks the location of the orbits of the x1mul2 family that also contribute to the reinforcement of a b/p morphology of the galactic bulge.

A characteristic examples of a sticky chaotic orbit that support simultaneously boxy edge-on and face-on morphologies are given in (b).

These sticky chaotic orbits exist in a certain range of energies. The face-on views of two more peanut-supporting orbits are given in (c) and (d) (Patsis & Katsanikas 2014b).


Patsis P.A., Katsanikas M., 2014a, MNRAS 445, 3525 (arxiv)
Patsis P.A., Katsanikas M., 2014b, MNRAS 445, 3546 (arxiv)
Skokos Ch., Patsis P.A., Athanassoula E., 2002, MNRAS 333, 847
Vrahatis M., Isliker H., Bountis T.C., 1997, IJBC 7, 2707

For a detailed study of the phase space in 3D rotating Hamiltonian systems see:
Katsanikas M., Patsis P.A., Contopoulos G., 2013, IJBC 23, 1330005
Katsanikas M., Patsis P.A., Contopoulos G., 2011, IJBC 21, 2321
Katsanikas M., Patsis P.A., 2011, IJBC 21, 467


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