S. A. Khoperskov

Global gravitationally organized spiral waves and the structure of NGC 5247

Using observational data, we build numerical N-body, hydrodynamical and combined equilibrium models for the spiral galaxy NGC 5247. The models turn out to be unstable as regards spiral structure formation. We simulate scenarios of spiral structure formation for different sets of equilibrium rotation curves, radial velocity-dispersion profiles and disc thicknesses and demonstrate that in all cases the simulated spiral pattern agrees qualitatively with the observed morphology of NGC 5247. We also demonstrate that an admixture of a gaseous component with a mass of about a few per cent of the total mass of the disc increases the lifetime of a spiral pattern by approximately 30 per cent. The simulated spiral pattern in this case lasts for about 3 Gyr from the beginning of the growth of perturbations.

Giant molecular cloud scaling relations: the role of the cloud definition

We investigate physical properties of molecular clouds in disc galaxies with different morphology: a galaxy without prominent structure, a spiral barred galaxy and a galaxy with flocculent structure. Our N -body/hydrodynamical simulations take into account non-equilibrium H2 and CO chemical kinetics, self-gravity, star formation and feedback processes. For the simulated galaxies the scaling relations of giant molecular clouds or so called Larson’s relations are studied for two types of a cloud definition (or extraction methods): the first one is based on total column density position-position (PP) datasets and the second one is indicated by the CO (1-0) line emission used position-position-velocity (PPV) data. We find that the cloud populations obtained by using both cloud extraction methods generally have similar physical parameters. Except that for the CO data the mass spectrum of clouds has a tail with low-massive objects M ∼ 10 − 10 M . Varying column density threshold the power-law indices in the scaling relations are significantly changed. In contrast, the relations are invariant to CO brightness temperature threshold. Finally, we find that the mass spectra of clouds for the PPV data are almost insensitive to the galactic morphology, whereas the spectra for the PP data demonstrate significant variations.

Numerical code for multi-component galaxies: from N-body to chemistry and magnetic fields

We present a numerical code for multi-component simulation of the galactic evolution. Our code includes the following parts:

The disc origin of the Milky Way bulge: Dissecting the chemo-morphological relations using N-body simulations and APOGEE

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Phylogeny of the Milky Way’s inner disk and bulge populations: Implications for gas accretion, (the lack of) inside-out thick disk formation, and quenching

-body is used to evolve dark matter, stellar dynamics and dust grains, gas dynamics is based on TVD-MUSCL scheme with the extra modules for thermal processes, star formation, magnetic fields, chemical kinetics and multi-species advection. We describe our code in brief, but we give more details for the magneto-gas dynamics. We present several tests for our code and show that our code have passed the tests with a reasonable accuracy. Our code is parallelized using the MPI library. We apply our code to study the large scale dynamics of galactic discs.

Synthetic HI observations of spiral structure in the outer disk in galaxies

There is a long-standing debate on the origin of the metal-poor stellar populations of the Milky Way (MW) bulge, with the two leading scenarios being that these populations are either i) part of a classical metal-poor spheroid or ii) the same population as the chemically defined thick disc seen at the Solar neighbourhood. Here we test whether the latter scenario can reproduce the observed chemical properties of the MW bulge. To do so we compare an N-body simulation of a composite (thin+thick) stellar disc -- which evolves secularly to form a bar and a boxy/peanut (b/p) bulge -- to data from APOGEE DR13. This model, in which the thick disc is massive and centrally concentrated, can reproduce the morphology of the metal-rich and metal-poor stellar populations in the bulge, as well as the mean metallicity and [

Disk heating and bending instability in galaxies with counterrotation

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Giant molecular clouds in M33: are they susceptible to dynamical friction?

/Fe] maps as obtained from the APOGEE data. It also reproduces the trends, in both longitude and latitude, of the bulge metallicity distribution function (MDF). Additionally, we show that the model predicts small but measurable azimuthal metallicity variations in the inner disc due to the differential mapping of the thin and thick disc in the bar. We therefore see that the chemo-morphological relations of stellar populations in the MW bulge are naturally reproduced by mapping the thin and thick discs of the inner MW into a b/p.

Global enhancement and structure formation of the magnetic field in spiral galaxies

We show that the bulge and the disk of the Milky Way (MW) at R

Mergers, tidal interactions, and mass exchange in a population of disc globular clusters

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