scholarly journals Tidal disruption events on to stellar black holes in triples

2019 ◽  
Vol 489 (1) ◽  
pp. 727-737 ◽  
Author(s):  
Giacomo Fragione ◽  
Nathan W C Leigh ◽  
Rosalba Perna ◽  
Bence Kocsis
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Force ◽  
Main Sequence ◽  
Initial Conditions ◽  
Main Sequence Stars ◽  
Tidal Disruption ◽  
Mean Velocity ◽  
Massive Black Holes ◽  
The Mean

ABSTRACT Stars passing too close to a black hole can produce tidal disruption events (TDEs), when the tidal force across the star exceeds the gravitational force that binds it. TDEs have usually been discussed in relation to massive black holes that reside in the centres of galaxies or lurk in star clusters. We investigate the possibility that triple stars hosting a stellar black hole (SBH) may be sources of TDEs. We start from a triple system made up of three main-sequence stars and model the supernova (SN) kick event that led to the production of an inner binary comprised of an SBH. We evolve these triples with a high-precision N-body code and study their TDEs as a result of Kozai–Lidov oscillations. We explore a variety of distributions of natal kicks imparted during the SN event, various maximum initial separations for the triples, and different distributions of eccentricities. We show that the main parameter that governs the properties of the SBH–MS binaries that produce a TDE in triples is the mean velocity of the natal kick distribution. Smaller σ’s lead to larger inner and outer semimajor axes of the systems that undergo a TDE, smaller SBH masses, and longer time-scales. We find that the fraction of systems that produce a TDE is roughly independent of the initial conditions, while estimate a TDE rate of $2.1\times 10^{-4}{\!-\!}4.7 \, \mathrm{yr}^{-1}$, depending on the prescriptions for the SBH natal kicks. This rate is almost comparable to the expected TDE rate for massive black holes.

scholarly journals Tidal disruption events from massive black hole binaries: predictions for ongoing and future surveys

2019 ◽  
Vol 488 (3) ◽  
pp. 4042-4060 ◽  
Author(s):  
Stephen Thorp ◽  
Eli Chadwick ◽  
Alberto Sesana
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Low Frequency ◽  
Mass Range ◽  
Tidal Disruption ◽  
Massive Black Hole ◽  
Massive Black Holes ◽  
X Ray ◽  
Black Hole Binaries ◽  
Survey Instruments

ABSTRACT We compute the expected cosmic rates of tidal disruption events (TDEs) induced by individual massive black holes (MBHs) and by MBH binaries (MBHBs) – with a specific focus on the latter class – to explore the potential of TDEs to probe the cosmic population of sub-pc MBHBs. Rates are computed by combining MBH and MBHB population models derived from large cosmological simulations with estimates of the induced TDE rates for each class of objects. We construct empirical TDE spectra that fit a large number of observations in the optical, UV, and X-ray and consider their observability by current and future survey instruments. Consistent with results in the literature, and depending on the detailed assumption of the model, we find that LSST and Gaia in optical and eROSITA in X-ray will observe a total of 3000–6000, 80–180, and 600–900 TDEs per year, respectively. Depending on the survey, 1 to several per cent of these are prompted by MBHBs. In particular, both LSST and eROSITA are expected to see 150–450 MBHB-induced TDEs in their respective mission lifetimes, including 5–100 repeated flares. The latter provide an observational sample of binary candidates with relatively low contamination and have the potential of unveiling the sub-pc population of MBHBs in the mass range $10^5\lt M\lt 10^7\, \mathrm{M}_\odot$, thus informing future low-frequency gravitational wave observatories.

scholarly journals Tidal disruption events from different kinds of astrophysical objects: a preliminary analysis

2016 ◽  
Vol 12 (S324) ◽  
pp. 132-133
Author(s):  
Aurora Clerici ◽  
Andreja Gomboc
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Preliminary Analysis ◽  
Tidal Disruption ◽  
Massive Black Hole ◽  
Massive Black Holes ◽  
Astrophysical Objects

AbstractTidal disruption events are a powerful tool to study quiescent massive black holes residing in the centre of galaxies. Occasionally, astrophysical objects such as stars, planets and smaller bodies are captured and tidally disrupted by the massive black hole, giving rise to a luminous flare. A detailed study of disruption parameters and the emitted radiation can give important insights on the black hole and its surroundings.

scholarly journals Formation and Evolution of Massive Black Holes in Star Clusters

2005 ◽  
Vol 13 ◽  
pp. 350-353
Author(s):  
Holger Baumgardt ◽  
Junichiro Makino ◽  
Simon Portegies Zwart
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Initial Conditions ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Young Star ◽  
Cluster Center ◽  
Massive Black Hole ◽  
Massive Black Holes ◽  
Equilibrium Profile

AbstractWe present results of N-body simulations on the formation of massive black holes by run-away merging in young star clusters and the later dynamical evolution of star clusters containing massive black holes. We determine the initial conditions necessary for run-away merging to form a massive black hole and study the equilibrium profile that is established in the cluster center as a result of the interaction of stars with the central black hole. Our results show that star clusters which contain black holes have projected luminosity profiles that can be fitted by standard King models. The presence of massive black holes in (post-)core collapse clusters is therefore ruled out by our simulations.

scholarly journals The thermodynamics of collapsars

2016 ◽  
Author(s):  
Trevor W. Marshall
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Stars ◽  
Main Sequence ◽  
Main Sequence Stars ◽  
Field Equations ◽  
Gravitational Radius ◽  
Final Density ◽  
Shell Models ◽  
Independent Case

This article argues that there is a consistent description of gravitationally collapsed bodies, including neutron stars above the Tolman-Oppenheimer-Volkoff mass and also supermassive galactic centres, according to which collapse stops before the object reaches its gravitational radius, the density reaching a maximum close to the surface and then decreasing towards the centre. Models for such shell-like objects have been constructed using classic formulations found in the 1939 articles of Oppenheimer-Volkoff and Oppenheimer-Snyder. It was possible to modify the conclusions of the first article by changing the authors’ boundary conditions at r = 0. In the second case we find that the authors’ solution of the field equations needs no changes, but that the choice of their article’s title led many of their successors to believe that it supports the black-hole hypothesis. However, it is easily demonstrated that their final density distribution accords with the shell models found in our articles. Because black holes, according to many formulations, "have no hair", their thermodynamics is rather simple. The kind of collapsar which our models describe are more like main-sequence stars; they have spatiotemporal distributions of pressure, density and temperature, that is they have hair. In this article we shall concentrate on the dynamics of the Oppenheimer-Snyder collapsar; both pressure and temperature are everywhere zero, so there can be no thermodynamics. Only in the time independent case of Oppenheimer-Volkoff type models is it currently feasible to consider some thermodynamic implications; here some valuable new insights are obtained through the incorporation of the Oppenheimer-Snyder dynamics.

scholarly journals Discovering intermediate massive black holes through tidally disrupted stars

2019 ◽  
Vol 28 (14) ◽  
pp. 1944015
Author(s):  
Martina Toscani ◽  
Giuseppe Lodato ◽  
Elena Maria Rossi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Laser Interferometer ◽  
Point Of View ◽  
Frequency Range ◽  
Tidal Disruption ◽  
Massive Black Holes ◽  
Binding Force ◽  
Laser Interferometer Space Antenna ◽  
Self Gravity

Stars are spheres of gas held together by self-gravity. When flying by a black hole, however, the star self-binding force can be overwhelmed by the black hole tides and the star can be torn apart. This is a physically rich and fascinating event which will be described by first introducing the concept of black hole from a mathematical point of view. We will then dive into the physics of the tidal disruption and proceed describing the accompanying electromagnetic flare and gravitational wave burst in the frequency range of the Laser Interferometer Space Antenna. This empowers such events to discover the elusive black holes with mass intermediate between the solar and the million/billion solar masses.

scholarly journals A loud quasi-periodic oscillation after a star is disrupted by a massive black hole

Science ◽  
2019 ◽  
Vol 363 (6426) ◽  
pp. 531-534 ◽  
Author(s):  
Dheeraj R. Pasham ◽  
Ronald A. Remillard ◽  
P. Chris Fragile ◽  
Alessia Franchini ◽  
Nicholas C. Stone ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Periodic Oscillation ◽  
Host Galaxy ◽  
X Rays ◽  
Tidal Disruption ◽  
Massive Black Hole ◽  
Quasi Periodic Oscillation ◽  
Massive Black Holes ◽  
Tidal Forces

The tidal forces close to massive black holes can rip apart stars that come too close to them. As the resulting stellar debris spirals toward the black hole, the debris heats up and emits x-rays. We report observations of a stable 131-second x-ray quasi-periodic oscillation from the tidal disruption event ASASSN-14li. Assuming the black hole mass indicated by host galaxy scaling relations, these observations imply that the periodicity originates from close to the event horizon and that the black hole is rapidly spinning. Our findings demonstrate that tidal disruption events can generate quasi-periodic oscillations that encode information about the physical properties of their black holes.

scholarly journals Gravitational waves from bodies orbiting the Galactic center black hole and their detectability by LISA

2019 ◽  
Vol 627 ◽  
pp. A92 ◽  
Author(s):  
E. Gourgoulhon ◽  
A. Le Tiec ◽  
F. H. Vincent ◽  
N. Warburton
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Main Sequence ◽  
Signal To Noise Ratio ◽  
Brown Dwarfs ◽  
Compact Objects ◽  
Main Sequence Stars ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Sgr A

Aims. We present the first fully relativistic study of gravitational radiation from bodies in circular equatorial orbits around the massive black hole at the Galactic center, Sgr A* and we assess the detectability of various kinds of objects by the gravitational wave detector LISA. Methods. Our computations are based on the theory of perturbations of the Kerr spacetime and take into account the Roche limit induced by tidal forces in the Kerr metric. The signal-to-noise ratio in the LISA detector, as well as the time spent in LISA band, are evaluated. We have implemented all the computational tools in an open-source SageMath package, within the Black Hole Perturbation Toolkit framework. Results. We find that white dwarfs, neutrons stars, stellar black holes, primordial black holes of mass larger than 10−4 M⊙, main-sequence stars of mass lower than ∼2.5 M⊙, and brown dwarfs orbiting Sgr A* are all detectable in one year of LISA data with a signal-to-noise ratio above 10 for at least 105 years in the slow inspiral towards either the innermost stable circular orbit (compact objects) or the Roche limit (main-sequence stars and brown dwarfs). The longest times in-band, of the order of 106 years, are achieved for primordial black holes of mass ∼10−3 M⊙ down to 10−5 M⊙, depending on the spin of Sgr A*, as well as for brown dwarfs, just followed by white dwarfs and low mass main-sequence stars. The long time in-band of these objects makes Sgr A* a valuable target for LISA. We also consider bodies on close circular orbits around the massive black hole in the nucleus of the nearby galaxy M 32 and find that, among them, compact objects and brown dwarfs stay for 103–104 years in LISA band with a one-year signal-to-noise ratio above ten.

scholarly journals The gravitational wave background signal from tidal disruption events

2020 ◽  
Vol 498 (1) ◽  
pp. 507-516 ◽  
Author(s):  
Martina Toscani ◽  
Elena M Rossi ◽  
Giuseppe Lodato
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Globular Clusters ◽  
White Dwarfs ◽  
Main Sequence ◽  
Big Bang ◽  
The Other ◽  
Main Sequence Stars ◽  
Background Signal ◽  
Tidal Disruption

ABSTRACT In this paper, we derive the gravitational wave stochastic background from tidal disruption events (TDEs). We focus on both the signal emitted by main-sequence stars disrupted by supermassive black holes (SMBHs) in galaxy nuclei and on that from disruptions of white dwarfs by intermediate-mass black holes (IMBHs) located in globular clusters. We show that the characteristic strain hc’s dependence on frequency is shaped by the pericenter distribution of events within the tidal radius and under standard assumptions hc∝f−1/2. This is because, the TDE signal is a burst of gravitational waves at the orbital frequency of the closest approach. In addition, we compare the background characteristic strains with the sensitivity curves of the upcoming generation of space-based gravitational wave interferometers: the Laser Interferometer Space Antenna (LISA), TianQin, ALIA, the DECI-hertz inteferometer Gravitational wave Observatory (DECIGO), and the Big Bang Observer (BBO). We find that the background produced by main-sequence stars might be just detected by BBO in its lowest frequency coverage, but it is too weak for all the other instruments. On the other hand, the background signal from TDEs with white dwarfs will be within reach of ALIA, and especially of DECIGO and BBO, while it is below the LISA and TianQin sensitive curves. This background signal detection will not only provide evidence for the existence of IMBHs up to redshift z ∼ 3, but it will also inform us on the number of globular clusters per galaxy and on the occupation fraction of IMBHs in these environments.

scholarly journals Tidal Disruption Events and stellar-mass black holes in OGLE and Gaia surveys

2016 ◽  
Vol 12 (S324) ◽  
pp. 127-131
Author(s):  
Łukasz Wyrzykowski ◽  
A. Hamanowicz ◽  
K. A. Rybicki
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Mass Distribution ◽  
Milky Way ◽  
Black Hole Mass ◽  
Tidal Disruption ◽  
Massive Black Holes ◽  
Mass Growth ◽  
Highly Active ◽  
Different Levels

AbstractTidal Disruption Events (TDE) allow to probe the super massive black holes (SMBH) in the cores of galaxies and could be a source of black hole mass growth. We present the search for candidates for TDEs conducted within OGLE and Gaia surveys. Our preliminary results indicate that TDEs can occur in cores of galaxies exhibiting different levels of activity, from quiescent, through weak-AGNs to highly active QSOs. We also present how Gaia can help study the mass distribution of Milky Way single black holes via microlensing.

scholarly journals The Process of Stellar Tidal Disruption by Supermassive Black Holes

2021 ◽  
Vol 217 (3) ◽  
Author(s):  
E. M. Rossi ◽  
N. C. Stone ◽  
J. A. P. Law-Smith ◽  
M. Macleod ◽  
G. Lodato ◽  
...  
Keyword(s):  
Black Holes ◽  
Initial Conditions ◽  
Numerical Models ◽  
Binary Star ◽  
Tidal Disruption ◽  
Massive Black Hole ◽  
Accretion Flows ◽  
Simple Order ◽  
Order Of Magnitude ◽  
A Chain

AbstractTidal disruption events (TDEs) are among the brightest transients in the optical, ultraviolet, and X-ray sky. These flares are set into motion when a star is torn apart by the tidal field of a massive black hole, triggering a chain of events which is – so far – incompletely understood. However, the disruption process has been studied extensively for almost half a century, and unlike the later stages of a TDE, our understanding of the disruption itself is reasonably well converged. In this Chapter, we review both analytical and numerical models for stellar tidal disruption. Starting with relatively simple, order-of-magnitude physics, we review models of increasing sophistication, the semi-analytic “affine formalism,” hydrodynamic simulations of the disruption of polytropic stars, and the most recent hydrodynamic results concerning the disruption of realistic stellar models. Our review surveys the immediate aftermath of disruption in both typical and more unusual TDEs, exploring how the fate of the tidal debris changes if one considers non-main sequence stars, deeply penetrating tidal encounters, binary star systems, and sub-parabolic orbits. The stellar tidal disruption process provides the initial conditions needed to model the formation of accretion flows around quiescent massive black holes, and in some cases may also lead to directly observable emission, for example via shock breakout, gravitational waves or runaway nuclear fusion in deeply plunging TDEs.

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