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The Mass Fallback Rate of the Debris in Relativistic Stellar Tidal Disruption Events
Taj Jankovič, Andreja Gomboc, 2023, original scientific article

Keywords: Hydrodynamics, Black holes
Published in RUNG: 23.03.2023; Views: 221; Downloads: 7
.pdf Full text (1,98 MB)

The mass fallback rate of the debris in relativistic stellar tidal disruption events
Taj Jankovič, 2022, published scientific conference contribution abstract

Abstract: Highly energetic stellar tidal disruption events (TDEs) provide a way to study black hole characteristics and their environment. We simulate TDEs in a general relativistic and Newtonian description of a supermassive black hole's gravity. Stars, which are placed on parabolic orbits with different impact parameters, are constructed with the stellar evolution code MESA and therefore have realistic stellar density profiles. We focus our analysis on the mass fallback rate of the debris, which can trace the observed light curve of TDEs. I will present the dependence of the mass fallback rate of the debris on the impact parameter, stellar mass and age as well as the black hole's spin and the choice of the gravity's description.
Keywords: black hole physics, hydrodynamics, relativistic processes
Published in RUNG: 21.10.2022; Views: 477; Downloads: 2
URL Link to full text
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Bound debris in stellar TDEs
Taj Jankovič, A. Gomboc, Aurora Clerici, 2020

Keywords: tidal disruption, black hole, astronomy, astrophyiscs, hydrodynamics
Published in RUNG: 29.07.2021; Views: 1469; Downloads: 0
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A study of stellar debris dynamics during a tidal disruption event
Aurora Clerici, 2020, doctoral dissertation

Abstract: The number of observed tidal disruption events is increasing rapidly with the advent of new surveys. Thus, it is becoming increasingly important to improve TDE models using different stellar and orbital parameters. We study the dynamical behaviour of tidal disruption events produced by a massive black hole like Sgr A* by changing different initial orbital parameters, taking into account the observed orbits of S stars. Investigating different types of orbits and penetration factors is important since their variations lead to different timescales of the tidal disruption event debris dynamics, making mechanisms such as self-crossing and pancaking act strongly or weakly, thus affecting the circularisation and accretion disk formation. We have performed smoothed particle hydrodynamics simulations. Each simulation consists in modelling the star with $10^5$ particles, and the density profile is described by a polytrope with $\gamma$ = 5/3. The massive black hole is modelled with a generalised post-Newtonian potential, which takes into account relativistic effects of the Schwarzschild space-time. Our analyses find that mass return rate distributions of solar-like stars and S-like stars with same eccentricity have similar durations, but S-like stars have higher mass return rate, as expected due to their larger mass. Regarding debris circularisation, we identify four types of evolution, related to the mechanisms and processes involved during circularisation: in type 1 the debris does not circularise efficiently, hence a disk is not formed or is formed after relatively long time; in type 2 the debris slowly circularises and eventually forms a disk with no debris falling back; in type 3 the debris relatively quickly circularises and forms a disk while there is still debris falling back; finally, in type 4 the debris quickly and efficiently circularises, mainly through self-crossings and shocks, and forms a disk with no debris falling back. Finally, we find that the standard relation of circularisation radius $r_{\rm circ} = 2r_{\rm t}$ holds only for $\beta = 1$ and eccentricities close to parabolic.
Keywords: 07.05.Tp Computer modeling and simulation, 95.30.Lz Hydrodynamics, 98.35.Jk Galactic center, bar, circumnuclear matter, and bulge, 98.62.Js Galactic nuclei (including black holes), circumnuclear matter, and bulges, 98.62.Mw Infall, accretion, and accretion disks
Published in RUNG: 29.09.2020; Views: 2696; Downloads: 71
.pdf Full text (37,55 MB)

PHYSICS II - Exercises : Part 1: Hydrostatics and Hydrodynamics
Jurij Urbančič, other educational material

Abstract: The following script is the first part of selected exercises and examples from the topics of Hydrostatics and Hydrodynamics. They were collected during the academic year 2019/20 when I was holding Physics II tutorials for the study program Physics and Astrophysics I. level within the School of Science at the University of Nova Gorica. The source material I used is given in the Bibliography at the end. Hopefully, these exercise fill help in providing a more in-depth understanding of physical phenomena discussed during the lectures.
Keywords: Hydrostatics, Hydrodynamics, Physics 2
Published in RUNG: 07.05.2020; Views: 2310; Downloads: 0
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