Research Center for Astronomy



Tuesday 27 January 2015 (12:00)

MegaMorph: developing advanced galaxy decomposition software for multi-wavelength surveys

Marina Vika
National Observatory of Athens / IAASARS


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Featured Picture

The Speed of Arnold Diffusion

The phenomenon of Arnold diffusion is important in a number of applications in solar system dynamics and plasma physics. The above figure, published in Efthymiopoulos and Harsoula, Physica D, 2013 (in press), shows a visualization of Arnold diffusion in a set of variables arising after a so-called optimal normal form construction using a special computer-algebraic program. According to theory, at a crossing domain of multiple resonances, the normal form construction allows to express the equations of motion as a Hamiltonian system of two degrees of freedom. This is perturbed, however, by a third degree of freedom appearing in the so-called `remainder' of the normal form. After a very slow drift in this third dimension (corresponding, in the figure, to the long edge of the framed parallelepiped), the orbits by-pass the barriers (invariant tori) of the 2D dynamics, and thus transit from one resonance to another. The timescale for this phenomenon is millions, or billions of characteristic periods of the orbits (see Efthymiopoulos and Harsoula 2013 for details).

View previous Pictures of the Month here...

Astronomy Scholarship opportunities from the Academy of Athens

One (1) Postdoc Research Fellow in the field of "Non-linear phenomena in Galactic Disks".

Announcement in Greek (PDF File)

One (1) Fellow for the program "Dissemination of Scientific Results"

Announcement in Greek (PDF File)

For more information please contact:

Dr. Panos A. Patsis & Mrs Georgia Aggelopoulou (tel. 210-6597169 and 210 6597648 respectively)

RCAAM Activities Report for 2013 (in Greek and English)

Read and download the file here...


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