Solutions of the Einstein Equations for a Black Hole Surrounded by a Galactic Halo

Konoplya, R. A.; Zhidenko, A.

doi:10.3847/1538-4357/ac76bc

Cited by 58 publications

(14 citation statements)

References 34 publications

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“…Multiple models exist for the spacetime metric around a static and spherically symmetric black hole with a DM halo based on the Newtonian approximation, including the Navarro-Frenk-White (NFW) profile (Navarro et al 1996;Navarro et al 1997) and Burkert-Salucci profile (Burkert 1995;Salucci & Burkert 2000). See also Xu et al (2018), Jusufi et al (2019Jusufi et al ( , 2020, Xu et al (2020), and Konoplya & Zhidenko (2022).…”

Section: Introductionmentioning

confidence: 99%

Spacetime Metrics and Ringdown Waveforms for Galactic Black Holes Surrounded by a Dark Matter Spike

Daghigh

Kunstatter

2022

ApJ

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Theoretical models suggest the existence of a dark matter spike surrounding the supermassive black holes at the core of galaxies. The spike density is thought to obey a power law that starts at a few times the black hole horizon radius and extends to a distance, R sp, of the order of a kiloparsec. We use the Tolman–Oppenheimer–Volkoff equations to construct the spacetime metric representing a black hole surrounded by such a dark matter spike. We consider the dark matter to be a perfect fluid, but make no other assumption about its nature. The assumed power-law density provides in principle three parameters with which to work: the power-law exponent γ sp, the external radius R sp, and the spike density ρ DM sp at R sp. These in turn determine the total mass of the spike. We focus on Sagittarius A* and M87 for which some theoretical and observational bounds exist on the spike parameters. Using these bounds in conjunction with the metric obtained from the Tolman–Oppenheimer–Volkoff equations, we investigate the possibility of detecting the dark matter spikes surrounding these black holes via the gravitational waves emitted at the ringdown phase of black hole perturbations. Our results suggest that if the spike to black hole mass ratio is roughly constant, greater mass black holes require relatively smaller spike densities to yield potentially observable signals. We find that is unlikely for the spike in M87 to be detected via the ringdown waveform with currently available techniques unless its mass is roughly an order of magnitude larger than existing observational estimates. However, given that the signal increases with black hole mass, dark matter spikes might be observable for more massive galactic black holes in the not too distant future.

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Section: Introductionmentioning

confidence: 99%

Spacetime Metrics and Ringdown Waveforms for Galactic Black Holes Surrounded by a Dark Matter Spike

Daghigh

Kunstatter

2022

ApJ

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“…One may consider, say, determining the halo-core relation under the influence of the nuclear bulge [22,122] and see how will it affect the black hole geometry; (3) Recently, there are other methods considered by various authors concerning the effect of the dark matter halo on a black hole at the galactic center. [145][146][147] It would be interesting to perform a comparison between methods, generating a black hole solution with the soliton profile, and analyze its black hole properties.…”

Section: Discussionmentioning

confidence: 99%

Black Hole in Quantum Wave Dark Matter

Pantig

Овгун

2022

Fortschritte der Physik

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In this work, we explored the effect of the fuzzy dark matter (FDM) (or wave dark matter) halo on a supermassive black hole (SMBH). Such a dark matter introduces a soliton core density profile, and we treat it ideally as a spherical distribution that surrounds the SMBH located at its center. In this direction, we obtained a new metric due to the union of the black hole and dark matter spacetime geometries. We applied the solution to the two known SMBH ‐ Sgr. A* and M87* and used the empirical data for the shadow diameter by EHT to constrain the soliton core radius rnormalc$r_\text{c}$ given some values of the boson mass mnormalb$m_\text{b}$. Then, we examine the behavior of the shadow radius based on such constraints and relative to a static observer. We found that different shadow sizes are perceived at regions robsrc$r_\text{obs}>r_\text{c}$, and the deviation is greater for values mb<10−22$m_\text{b}<10^{-22}$ eV. Concerning the shadow behavior, we have also analyzed the effect of the soliton profile on the thin‐accretion disk. Soliton dark matter effects manifest through the varying luminosity near the event horizon. We also analyzed the weak deflection angle and the produced Einstein rings due to soliton effects. We found considerable deviation, better than the shadow size deviation, for the light source near the SMBH with impact parameters comparable to the soliton core. Our results suggest the possible experimental detection of soliton dark matter effects using an SMBH at the galactic centers.

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“…In this study, we ought to analyze such a metric under the influence of plasma and dark matter. With the shadow cast, it can also determine imprints of spacetime, and several studies were also conducted about using the black hole for dark matter detection [50,51,[59][60][61][62][63][64][65][66][67][68].…”

Section: Introductionmentioning

confidence: 99%

Weak Deflection Angle, Hawking Radiation and Greybody Bound of Reissner–Nordström Black Hole Corrected by Bounce Parameter

et al. 2023

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In this study, we probe the weak lensing by a Reissner–Nordström black hole corrected by bounce parameter in plasma and dark matter mediums. For this, the optical geometry and the Gibbons–Werner approach are utilized to obtain the bending angle in the weak field limitations. We examine that the impact of these mediums increases the black hole’s bending angle. In addition, we graphically study the deflection angle of light with respect to the impact parameter and examine that the bounce parameter directly affects the angle. Further, we compute the Hawking radiation via a topological method involving two invariants and verify our obtained result with the standard method of calculating the Hawking temperature. In addition, we compute the greybody factor’s bound of the black hole. Moreover, we analyze the bound graphically and observe that the bound shows convergent behavior. We also study that our attained results reduce the results of the Reissner–Nordström and Schwarzschild black holes by reducing the parameters. Finally, we probe how the bounce parameter affected the shadow radius and compared it to the shadow produced if the black hole is immersed in plasma. It is revealed that the rate at which the shadow radius changes with respect to r easily tends to zero under the effect of the bounce parameter, while the plasma merely increases the shadow radius.

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Solutions of the Einstein Equations for a Black Hole Surrounded by a Galactic Halo

Cited by 58 publications

References 34 publications

Spacetime Metrics and Ringdown Waveforms for Galactic Black Holes Surrounded by a Dark Matter Spike

Spacetime Metrics and Ringdown Waveforms for Galactic Black Holes Surrounded by a Dark Matter Spike

Black Hole in Quantum Wave Dark Matter

Weak Deflection Angle, Hawking Radiation and Greybody Bound of Reissner–Nordström Black Hole Corrected by Bounce Parameter

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