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Aleksandr Mylläri

Publications and source records attributed to Aleksandr Mylläri.

2 recordsLinked to original sources

The influence of spin in black hole triplets

Spin can influence the dynamics of the already chaotic black hole triplet system. We follow this problem in two sets of simulations: first, the Agekian-Anosova region (or region D), and second, using Pythagorean triangles. We use ARCcode, an N-body code that performs numerical integration of orbits. This code includes post-Newtonian corrections, which we include up to the 2.5th order. In set one of our simulations, we fix the masses of the black holes at 10$^{6}$ M$_{\odot}$. Then we run the simulations first without any spin added and after by initialising spin on one of the black holes. We find that after including spin into the system, 12.9% of the simulations changed outcomes. Either the systems went from having all black holes merging to having a black hole escaping the system, or vice versa. In the second set of simulations, we expanded into Pythagorean triangles as initial positions of black holes, stemming from Burrau's three-body problem. We varied the masses of the black holes from 10$^{0}$ M$_{\odot}$ to 10$^{12}$ M$_{\odot}$. Black holes in these systems were given spin in normalised units ranging from 0 to 0.95. We find that intermediate mass black holes in the range of 10$^{4}$ M$_{\odot}$-10$^{5}$ M$_{\odot}$, were influenced the most by spin, particularly in their lifetimes. We also find that simulations, initialised as 2D, become 3D.

astro-ph.GA↗

Relativistic Effects on Triple Black Holes: Burrau's Problem Revisited

We explore, using numerical simulations, the influence of mass and distance on the evolution of triple black hole systems. Following in the direction of Burrau's famous 3,4,5 problem, black holes are initially placed at the vertices of Pythagorean triangles. Numerical integration of orbits was conducted using relativistic corrections (post-Newtonian) up to the 2.5$^{th}$ order with ARCcode. As a descriptor of the evolution of the systems, the lifetimes, the number of two-body encounters and the number of mergers were all analysed. We found that as the mass unit of the black holes increased there was strong positive correlation with the fraction of mergers (0.9868), strong negative correlation with the average number of two-body encounters (-0.9016) and the average lifetimes of the triple systems decayed exponentially (determination coefficient of 0.9986). Around the mass unit range of 10$^{5.5}$M$_{\odot}$-10$^{5.6}$M$_{\odot}$, there was a transition from escape dominated dynamics to merger dominated dynamics. However, in the mass unit range of 10$^6$ M$_{\odot}$ $-$ 10$^{9}$M$_{\odot}$ with 1 pc distance unit, we find that 25\% of cases resulted in the escape of a supermassive black hole (SMBH) which may be a cause for wandering SMBH's found in some galaxies/galactic merger remnants.

astro-ph.GA↗