A Hidden Friend for the Galactic Center Black Hole, Sgr A*

Naoz, Smadar; Will, Clifford M.; Ramírez-Ruiz, E.; Hees, A.; Ghez, A. M.; Do, Tuan

doi:10.3847/2041-8213/ab5e3b

Cited by 58 publications

(49 citation statements)

References 89 publications

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“…On the other hand, at the center of our galaxy there is a supermassive BH of mass ∼ 4 × 10 6 M with known companions [40,41]. For the closest known star, S2, with a pericenter distance of ∼ 1400M BH we find ∼ 2×10 −15 , or a critical coupling M µ ∼ 9 × 10 −3 (we assume M c ∼ 20M but the result above is only mildly dependent on the unknown mass of S2).…”

Section: Application To Astrophysical Systemsmentioning

confidence: 63%

Tidal effects and disruption in superradiant clouds: A numerical investigation

2020

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The existence of light, fundamental bosonic fields is an attractive possibility that can be tested via black hole observations. We study the effect of a tidal field -caused by a companion star or black hole -on the evolution of superradiant scalar-field states around spinning black holes. For small tidal fields, the superradiant "cloud" puffs up by transitioning to excited states and acquires a new spatial distribution through transitions to higher multipoles, establishing new equilibrium configurations. For large tidal fields the scalar condensates are disrupted; we determine numerically the critical tidal moments for this to happen and find good agreement with Newtonian estimates. We show that the impact of tides can be relevant for known black-hole systems such as the one at the center of our galaxy or the Cygnus X-1 system. The companion of Cygnus X-1, for example, will disrupt possible scalar structures around the BH for gravitational couplings as large as M µ ∼ 2 × 10 −3 .

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Section: Application To Astrophysical Systemsmentioning

confidence: 63%

Tidal effects and disruption in superradiant clouds: A numerical investigation

2020

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“…A recent work discusses the presence of SMBH binary in our galactic center including the possibility of GW detection [75].…”

Section: Classification and Constraints On Parametersmentioning

confidence: 99%

Gravitational waves from hierarchical triple systems with Kozai-Lidov oscillation

et al. 2020

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We study gravitational waves from a hierarchical three-body system up to first-order post-Newtonian approximation. Under certain conditions, the existence of a nearby third body can cause periodic exchange between eccentricity of an inner binary and relative inclination, known as Kozai-Lidov oscillations. We analyze features of the waveform from the inner binary system undergoing such oscillations. We find that variation caused due to the tertiary companion can be observed in the gravitational waveforms and energy spectra, which should be compared with those from isolated binaries and coplanar three-body system. The detections from future space-based interferometers will make possible the investigation of gravitational wave spectrum in mHz range and may fetch signals by sources addressed.

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“…The bottom area is excluded because the gravitational wave inspiral time scale T GW would be <10 Myr. Naoz et al (2020) exclude the green shaded area by demanding that the S2 orbit be stable, taking into account resonant effects from the IMBH. Beyond the ranges given in the original work, the constraints get weaker (fading colour).…”

Section: Appendix D: Astrophysical Implicationsmentioning

confidence: 99%

Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole

Abuter

Amorim

Bauböck

et al. 2020

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426

204

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The star S2 orbiting the compact radio source Sgr A* is a precision probe of the gravitational field around the closest massive black hole (candidate). Over the last 2.7 decades we have monitored the star’s radial velocity and motion on the sky, mainly with the SINFONI and NACO adaptive optics (AO) instruments on the ESO VLT, and since 2017, with the four-telescope interferometric beam combiner instrument GRAVITY. In this Letter we report the first detection of the General Relativity (GR) Schwarzschild Precession (SP) in S2’s orbit. Owing to its highly elliptical orbit (e = 0.88), S2’s SP is mainly a kink between the pre-and post-pericentre directions of motion ≈±1 year around pericentre passage, relative to the corresponding Kepler orbit. The superb 2017−2019 astrometry of GRAVITY defines the pericentre passage and outgoing direction. The incoming direction is anchored by 118 NACO-AO measurements of S2’s position in the infrared reference frame, with an additional 75 direct measurements of the S2-Sgr A* separation during bright states (“flares”) of Sgr A*. Our 14-parameter model fits for the distance, central mass, the position and motion of the reference frame of the AO astrometry relative to the mass, the six parameters of the orbit, as well as a dimensionless parameter fSP for the SP (fSP = 0 for Newton and 1 for GR). From data up to the end of 2019 we robustly detect the SP of S2, δϕ ≈ 12′ per orbital period. From posterior fitting and MCMC Bayesian analysis with different weighting schemes and bootstrapping we find fSP = 1.10 ± 0.19. The S2 data are fully consistent with GR. Any extended mass inside S2’s orbit cannot exceed ≈0.1% of the central mass. Any compact third mass inside the central arcsecond must be less than about 1000 M⊙.

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A Hidden Friend for the Galactic Center Black Hole, Sgr A*

Cited by 58 publications

References 89 publications

Tidal effects and disruption in superradiant clouds: A numerical investigation

Tidal effects and disruption in superradiant clouds: A numerical investigation

Gravitational waves from hierarchical triple systems with Kozai-Lidov oscillation

Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole

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