Publications (8)
Galactic bar: normal mode of the stellar disk or superposition of transient spirals?
Evgeny Polyachenko
Several mechanisms of bar formation in stellar galactic disks are considered, including Toomre swing amplification and normal mode approach. On example of the well-known model of K…
Multiarm spirals on the periphery of disc galaxies
Lubov Spiegel, Evgeny Polyachenko
Spiral patterns in some disc galaxies have two arms in the centre, and three or more arms on the periphery. The same result is also obtained in numerical simulations of stellar and…
Geometric Entropy and Retrieval Phase Transitions in Continuous Thermal Dense Associative Memory
Tatiana Petrova, Evgeny Polyachenko, Radu State
We study the thermodynamic memory capacity of modern Hopfield networks (Dense Associative Memory models) with continuous states under geometric constraints, extending classical ana…
Swing amplification and global modes reciprocity in models with cusps
Evgeny Polyachenko
Using 3D N-body simulations we analyse an onset of the bar in cuspy models, and argue that role of swing amplification is twofold. Amplified shot noise due to disc discreteness ham…
Star-by-star dynamical evolution of the physical pair of the Collinder 135 and UBC 7 open clusters
Maryna Ishchenko, Dana A. Kovaleva, Peter Berczik +8
In a previous paper using Gaia DR2 data, we demonstrated that the two closely situated open clusters Collinder 135 and UBC 7 might have formed together about 50 Myr ago. In this wo…
Collinder 135 and UBC 7: A Physical Pair of Open Clusters
Dana Kovaleva, Marina Ishchenko, Ekaterina Postnikova +7
Given the closeness of the two open clusters Cr 135 and UBC 7 on the sky, we investigate the possibility of the two clusters to be physically related. We aim to recover the present…
Bisymmetric normal modes in soft-centred and realistic galactic discs
Evgeny Polyachenko, Andreas Just
We test methods for the determination of unstable modes in stellar discs: a point collocation scheme in the action sub-space, a scheme based on expansion of the density and potenti…
On the bar formation mechanism in galaxies with cuspy bulges
Evgeny Polyachenko, Peter Berczik, Andreas Just
We show by numerical simulations that a purely stellar dynamical model composed of an exponential disc, a cuspy bulge, and an NFW halo with parameters relevant to the Milky Way Gal…