A numerical study of Galactic Centre stars

2020 ◽  
Vol 501 (2) ◽  
pp. 2418-2423
Author(s):  
Oscar Salcido ◽  
Carlos Calcaneo-Roldan
Keyword(s):  
Black Hole ◽  
Numerical Study ◽  
Semimajor Axis ◽  
Galactic Centre ◽  
Central Black Hole ◽  
Central Object ◽  
Galactic Potential ◽  
The Galaxy ◽  
Inner Parts ◽  
Strong Agreement

ABSTRACT We present a simulation of the orbits of Galactic Centre stars, also known as ‘S-stars’, with the purpose of describing the motion of those bodies for which complete orbits are known with greater accuracy. The aim is to have a better understanding of the inner parts of the Galactic potential. The simulation assumes that the spacetime around the central black hole of the Galaxy may be modelled by the Schwarzschild metric, while stellar interactions are approximated classically. We model the central object as a black hole with mass 4.31 × 106 M⊙, fix the Galactic Centre distance at R = 8.33 kpc and include 37 orbiting stars, all of which have masses of 10 M⊙, except for S2, which has a mass of 20 M⊙. Our method allows us to predict the semimajor axis, a; eccentricity, ϵ; and period, T for these stars and predict their periastron shift, δΘ. In particular for S2, the most scrutinized star, we find δΘ = 11.9342 arcmin, in strong agreement with the observed value.

scholarly journals Hypervelocity stars from star clusters hosting intermediate-mass black holes

2019 ◽  
Vol 489 (4) ◽  
pp. 4543-4556 ◽  
Author(s):  
Giacomo Fragione ◽  
Alessia Gualandris
Keyword(s):  
Black Hole ◽  
High Velocity ◽  
Globular Clusters ◽  
Galactic Centre ◽  
Galactic Latitude ◽  
Dark Halo ◽  
Intermediate Mass ◽  
Galactocentric Distance ◽  
Galactic Potential ◽  
The Galaxy

ABSTRACT Hypervelocity stars (HVSs) represent a unique population of stars in the Galaxy reflecting properties of the whole Galactic potential. Determining their origin is of fundamental importance to constrain the shape and mass of the dark halo. The leading scenario for the ejection of HVSs is an encounter with the supermassive black hole in the Galactic centre. However, new proper motions from the Gaia mission indicate that only the fastest HVSs can be traced back to the Galactic centre and the remaining stars originate in the disc or halo. In this paper, we study HVSs generated by encounters of stellar binaries with an intermediate-mass black hole (IMBH) in the core of a star cluster. For the first time, we model the effect of the cluster orbit in the Galactic potential on the observable properties of the ejected population. HVSs generated by this mechanism do not travel on radial orbits consistent with a Galactic centre origin, but rather point back to their parent cluster, thus providing observational evidence for the presence of an IMBH. We also model the ejection of high-velocity stars from the Galactic population of globular clusters, assuming that they all contain an IMBH, including the effects of the cluster’s orbit and propagation of the star in the Galactic potential up to detection. We find that high-velocity stars ejected by IMBHs have distinctive distributions in velocity, Galactocentric distance and Galactic latitude, which can be used to distinguish them from runaway stars and stars ejected from the Galactic Centre.

scholarly journals A Nonparametric Estimate of the Mass of the Central Black Hole in the Galaxy

2001 ◽  
Vol 122 (1) ◽  
pp. 232-241 ◽  
Author(s):  
Dalia Chakrabarty ◽  
Prasenjit Saha
Keyword(s):  
Black Hole ◽  
Nonparametric Estimate ◽  
Central Black Hole ◽  
The Galaxy

scholarly journals Interaction of stars hosting planets with Sgr A* black hole

2019 ◽  
Vol 14 (S351) ◽  
pp. 76-79 ◽  
Author(s):  
Nazanin Davari ◽  
Roberto Capuzzo-Dolcetta ◽  
Rainer Spurzem
Keyword(s):  
Black Hole ◽  
Planetary Systems ◽  
Galactic Centre ◽  
Central Black Hole ◽  
Preliminary Results ◽  
Close Interaction ◽  
Sgr A ◽  
Ongoing Project

AbstractWe present some preliminary results of our ongoing project about planetary systems around S-stars in the vicinity of Sgr A* black hole. Since S-stars might have migrated in the Galactic Centre (GC) from elsewhere, they probably still keep their planetary systems throughout their voyage. In this work, we study the destiny of their putative planetary systems after close interaction with the central black hole of our galaxy.

scholarly journals 10.2. High proper motions in the vicinity of Sgr A∗: unambiguous evidence for a massive central black hole

1998 ◽  
Vol 184 ◽  
pp. 433-434
Author(s):  
A. M. Ghez ◽  
B. L. Klein ◽  
C. McCabe ◽  
M. Morris ◽  
E. E. Becklin
Keyword(s):  
Black Hole ◽  
Milky Way ◽  
Galactic Center ◽  
Robust Method ◽  
Proper Motions ◽  
Central Black Hole ◽  
Milky Way Galaxy ◽  
The Galaxy ◽  
Sgr A

Although the notion that the Milky Way galaxy contains a supermassive central black hole has been around for more than two decades, it has been difficult to prove that one exists. The challenge is to assess the distribution of matter in the few central parsecs of the Galaxy. Assuming that gravity is the dominant force, the motion of the stars and gas in the vicinity of the putative black hole offers a robust method for accomplishing this task, by revealing the mass interior to the radius of the objects studied. Thus objects located closest to the Galactic Center provide the strongest constraints on the black hole hypothesis.

scholarly journals Evidence for jet driven outflows: the case of 3C293

2014 ◽  
Vol 10 (S313) ◽  
pp. 289-293
Author(s):  
E. K. Mahony ◽  
J. B. R. Oonk ◽  
R. Morganti ◽  
T. A. Oosterloo ◽  
B. H. C. Emonts ◽  
...  
Keyword(s):  
Black Hole ◽  
Galaxy Evolution ◽  
Direct Evidence ◽  
Host Galaxy ◽  
Central Black Hole ◽  
Radio Jets ◽  
Neutral Gas ◽  
The Galaxy ◽  
Mass Outflow ◽  
Gas Quenching

AbstractThe tight correlations observed between galaxies and their SMBH provides compelling evidence that the evolution of the galaxy and its central black hole are strongly linked. This is generally attributed to feedback mechanisms which, according to simulations, often take the form of outflows of gas, quenching star formation in the host galaxy and halting accretion onto the central black hole. While there are a number of plausible ways that outflows could be produced, recent results have shown that in some cases radio jets could be responsible for driving fast outflows of gas. One such example is seen in the nearby radio galaxy 3C293. In this talk I will present results from JVLA radio observations where we detect fast outflows (~1200 km/s) of neutral gas which are being driven by the radio-jet approximately 0.5 kpc from the central core, providing direct evidence for jet-ISM interaction. This is accompanied with recent IFU observations showing that ionised gas outflows are also being driven by the radio jet. Pinpointing the location of these outflows enables us to derive crucial parameters, such as the mass outflow rates and kinetic energy involved, which we can compare to predictions from galaxy evolution simulations.

scholarly journals The secular evolution of discrete quasi-Keplerian systems

2018 ◽  
Vol 609 ◽  
pp. A38 ◽  
Author(s):  
J.-B. Fouvry ◽  
C. Pichon ◽  
P.-H. Chavanis
Keyword(s):  
Black Hole ◽  
Landau Equation ◽  
Collective Effects ◽  
Galactic Centre ◽  
Central Black Hole ◽  
Massive Black Hole ◽  
Secular Evolution ◽  
Gauss Method ◽  
And Diffusion ◽  
Keplerian Systems

A discrete self-gravitating quasi-Keplerian razor-thin axisymmetric stellar disc orbiting a massive black hole sees its orbital structure diffuse on secular timescales as a result of a self-induced resonant relaxation. In the absence of collective effects, such a process is described by the recently derived inhomogeneous multi-mass degenerate Landau equation. Relying on Gauss’ method, we computed the associated drift and diffusion coefficients to characterise the properties of the resonant relaxation of razor-thin discs. For a disc-like configuration in our Galactic centre, we showed how this secular diffusion induces an adiabatic distortion of orbits and estimate the typical timescale of resonant relaxation. When considering a disc composed of multiple masses similarly distributed, we have illustrated how the population of lighter stars will gain eccentricity, driving it closer to the central black hole, provided the distribution function increases with angular momentum. The kinetic equation recovers as well the quenching of the resonant diffusion of a test star in the vicinity of the black hole (the “Schwarzschild barrier”) as a result of the divergence of the relativistic precessions. The dual stochastic Langevin formulation yields consistent results and offers a versatile framework in which to incorporate other stochastic processes.

scholarly journals Visible Shapes of Black Holes M87* and SgrA*

Universe ◽  
2020 ◽  
Vol 6 (9) ◽  
pp. 154
Author(s):  
Vyacheslav I. Dokuchaev ◽  
Natalia O. Nazarova
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Milky Way ◽  
Dark Spot ◽  
Disk Model ◽  
Milky Way Galaxy ◽  
Supermassive Black Hole ◽  
The Galaxy ◽  
Visible Images ◽  
Inner Parts

We review the physical origins for possible visible images of the supermassive black hole M87* in the galaxy M87 and SgrA* in the Milky Way Galaxy. The classical dark black hole shadow of the maximal size is visible in the case of luminous background behind the black hole at the distance exceeding the so-called photon spheres. The notably smaller dark shadow (dark silhouette) of the black hole event horizon is visible if the black hole is highlighted by the inner parts of the luminous accreting matter inside the photon spheres. The first image of the supermassive black hole M87*, obtained by the Event Horizon Telescope collaboration, shows the lensed dark image of the southern hemisphere of the black hole event horizon globe, highlighted by accreting matter, while the classical black hole shadow is invisible at all. A size of the dark spot on the Event Horizon Telescope (EHT) image agrees with a corresponding size of the dark event horizon silhouette in a thin accretion disk model in the case of either the high or moderate value of the black hole spin, a≳0.75.

scholarly journals 11.1. Black holes and galaxy centers

1998 ◽  
Vol 184 ◽  
pp. 451-458 ◽  
Author(s):  
Douglas Richstone
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Central Black Hole ◽  
The Core ◽  
Supermassive Black Hole ◽  
Normal Galaxy ◽  
The Galaxy ◽  
Major Review

The study of supermassive galactic black holes (BH) has moved beyond discovery to maturity. The are now ∼ 15 reliable detections. The mass of a central black hole apparently correlates with the mass of the hot component of its galactic host. It may be that every normal galaxy has a supermassive black hole carrying about 10−3 of its bulge mass, with important consequences for the structure and evolution of the core of the galaxy. The most recent major review is by Kormendy & Richstone (1995, KR).

Survival Probability for a Hypervelocity Star in Close Neighborhood of a Supermassive Black Hole

2015 ◽  
Vol 24 (1) ◽  
pp. 1-8 ◽  
Author(s):  
G. Dryomova ◽  
V. Dryomov ◽  
A. Tutukov
Keyword(s):  
Numerical Simulation ◽  
Black Hole ◽  
Body Problem ◽  
Close Binary System ◽  
Close Binary ◽  
Ejection Velocity ◽  
Three Body Problem ◽  
Central Black Hole ◽  
The Galaxy ◽  
Three Body

AbstractWe present the results of numerical simulation on the probability of formation of a Hypervelocity Star (HVS) in the scenario of dynamic capture of a close binary system by the central black hole in the Galaxy and on the probability of its survival in the strong tidal field in the vicinity of the black hole. The results have been obtained for a series of pericentric distances. We applied a two-level numerical simulation implemented at first in the framework of the three-body problem used for evaluation of the HVS ejection velocity and then as an

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