198 research outputs found
Star Clusters and Super Massive Black Holes: High Velocity Stars Production
One possible origin of high velocity stars in the Galaxy is that they are the
product of the interaction of binary systems and supermassive black holes. We
investigate a new production channel of high velocity stars as due to the close
interaction between a star cluster and supermassive black holes in galactic
centres. The high velocity acquired by some stars of the cluster comes from
combined effect of extraction of their gravitational binding energy and from
the slingshot due to the interaction with the black holes. Stars could reach a
velocity sufficient to travel in the halo and even overcome the galactic
potential well, while some of them are just stripped from the cluster and start
orbiting around the galactic centre.Comment: 2 pages, 1 figure. Presented at the MODEST 16/Cosmic Lab conference
in Bologna, Italy, April 18-22 2016. To be pusblshed in Mem. S.A.It.
Conference Serie
High performance computing for classic gravitational N-body systems
The role of gravity is crucial in astrophysics. It determines the evolution
of any system, over an enormous range of time and space scales. Astronomical
stellar systems as composed by N interacting bodies represent examples of
self-gravitating systems, usually treatable with the aid of newtonian gravity
but for particular cases. In this note I will briefly discuss some of the open
problems in the dynamical study of classic self-gravitating N-body systems,
over the astronomical range of N. I will also point out how modern research in
this field compulsorily requires a heavy use of large scale computations, due
to the contemporary requirement of high precision and high computational speed.Comment: Invited talk presented at the CSFI 2008 Conference (Rimini, Italy,
may 27-may 31 2008); 4 pages including one table. Latex: requires
\documentclass{cimento}. In press in the Conference Proceedings published as
a copy of Il Nuovo Cimento journa
The MEGaN project I. Missing formation of massive nuclear clusters and tidal disruption events by star clusters - massive black hole interactions
We investigated the evolution of a massive galactic nucleus hosting a
super-massive black hole (SMBH) with mass surrounded by a population of 42 heavy star clusters (GCs).
Using direct -body modelling, we show here that the assembly of an NSC
through GCs orbital decay and merger is efficiently inhibited by the tidal
forces exerted from the SMBH. The GCs mass loss induced by tidal forces causes
a significant modification of their mass function, leading to a population of
low-mass () clusters. Nonetheless, the GCs debris accumulated around the
SMBH give rise to well-defined kinematical and morphological properties,
leading to the formation of a disk-like structure. Interestingly, the disk is
similar to the one observed in the M31 galaxy nucleus, which has properties
similar to our numerical model. The simulation produced a huge amount of data,
which we used to investigate whether the GC debris deposited around the SMBH
can enhance the rate of tidal disruption events (TDEs) in our galaxy inner
density distribution. Our results suggest that the GCs disruption shapes the
SMBH neighbourhoods leading to a TDE rate of yr,
a value slightly larger than what expected in previous theoretical modelling of
galaxies with similar density profiles and central SMBHs. The simulation
presented here is the first of its kind, representing a massive galactic
nucleus and its star cluster population on scales pc.Comment: 15 pages, 10 figures, 4 tables. Accepted for publication in MNRA
High-velocity stars from the interaction of a globular cluster and a massive black hole binary
High-velocity stars are usually thought to be the dynamical product of the interaction of binary systems with supermassive black holes. In this paper, we investigate a particular mechanism of production of high-velocity stars as due to the close interaction between a massive and orbitally decayed globular cluster and a supermassive black hole binary. The high velocity acquired by some stars of the cluster comes from combined effect of extraction of their gravitational binding energy and from the slingshot due to the interaction with the black hole binary. After the close interaction, stars could reach a velocity sufficient to travel in the halo and even overcome the galactic potential well, while some of them are just stripped from the globular cluster and start orbiting around the galactic centre
- …