Visible shapes of black holes M87* and SgrA*

Dokuchaev, V. I.; Nazarova, N. O.

doi:10.48550/arxiv.2007.14121

Cited by 5 publications

(6 citation statements)

References 75 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While the literature on the study of shadow cast is quite exhaustive before and after the release of the black hole image by the EHT, it leaves no doubt about the importance of studying the black hole shadow since it reveals imprints of the spacetime being considered, and the effects of any type of astrophysical environments . It led to various methods being developed to explore such effects [60][61][62][63][64][65][66][67][68]. This study aims to constrain the screening factor γ using the EHT data and explore how the shadow cast/radius behaves.…”

Section: Introductionmentioning

confidence: 99%

Shadow, lensing, quasinormal modes, greybody bounds and neutrino propagation by dyonic ModMax black holes

et al. 2022

View full text Add to dashboard Cite

Motivated by recent work on the Modified Maxwell (ModMax) black holes [Phys Lett B 10.1016/j.physletb.2020.136011], which are invariant in duality rotations and conformal transformations founded in [Phys Rev D 10.1103/PhysRevD.102.121703], we probe its effects on the shadow cast, weak field gravitational lensing, and neutrino propagation in its vicinity. Using the EHT data for the shadow diameter of Sgr. A* and M87*, and LIGO/VIRGO experiments for the dyonic ModMax black hole perturbations, we find constraints for ModMax parameters such as $$Q_\text {m}$$ Q m and the screening factor $$\gamma $$ γ . We also analyze how the shadow radius behaves as perceived by a static observer and one that is comoving with the cosmic expansion. The effect of the ModMax parameters is constant for a static observer, and we found That it varies when the observer is comoving with cosmic expansion. We also analyzed its effect on the weak deflection angle by exploiting the Gauss–Bonnet theorem and its application to Einstein ring formation. We also consider the finite distance effect and massive particle deflection. Our results indicate that the far approximation of massive particle gives the largest deflection angle and amplifies the effect of $$Q_\text {m}$$ Q m and $$\gamma $$ γ . Then we also calculate the quasinormal modes and greybody bounds which encode unique characteristic features of the dyonic ModMax black hole. With the advent of improving space technology, we reported that it is possible to detect the deviation caused through the shadow cast, Einstein rings, quasinormal modes, and neutrino oscillations.

show abstract

Section: Introductionmentioning

confidence: 99%

Shadow, lensing, quasinormal modes, greybody bounds and neutrino propagation by dyonic ModMax black holes

et al. 2022

View full text Add to dashboard Cite

show abstract

“…One notes that E, L and Ω do not depend on the scalar charge Σ, i.e., they coincide with those from the traditional Kerr black hole solution. Equation (7) for the ISCO takes the form:…”

Section: Circular Orbit a Kl Geometrymentioning

confidence: 99%

“…Images of black holes are actually obtained in the microwave range, but since we are dealing with geometric optics, optical terminology is quite appropriate. The optical view of a remote ultra-compact object illuminated by external sources can be very different depending on the geometric position of the source relative to the line of observation, the angle of inclination to the angular velocity of the object's rotation, the lighting scheme (backlight, radiation from accretion disks, and so on) [7] , the presence of plasma [5], dark matter [8][9][10] and many other factors. A common feature is the presence of a dark spot, corresponding to the absorption of photons by the object and usually associated with the event horizon.…”

Section: Introductionmentioning

confidence: 99%

Photon surfaces, shadows and accretion disks in gravity with minimally coupled scalar field

Bogush,

Gal'tsov,

Gyulchev

et al. 2022

Preprint

View full text Add to dashboard Cite

In this article, we conduct a sequential study of possible observable images of black hole simulators described by two recently obtained rotating geometries in Einstein gravity, minimally coupled to a scalar field. One of them, "Kerr-like" (KL), can be seen as a legitimate alternative to the rotating Fisher-Janis-Newman-Winicour (FJNW) solution, and the other (TSL) is a scalar generalization of the Tomimatsu-Sato solution. Unlike the previous version of the rotating FJNW, these solutions do indeed satisfy the system's equations of motion. Our study includes both analytical and numerical calculations of equatorial circular orbits, photon regions, gravitational shadows, and radiation from thin accretion disks for various values of the object's angular momentum and scalar charge. The TSL solution was found to simulate Kerr for all valid parameter values with high accuracy. The maximum difference between the deviations of shadows from a circle for the Kerr and TSL cases does not exceed 1% and fits into the experimental observational data M87 * . However, near-extreme objects show two times smaller peak values of the observed outflow luminosity of the accretion disk than for the Kerr black hole. The KL solution cannot be ruled out by the experimental data for small values of the scalar charge either. As the scalar charge increases, the optical properties change dramatically. The shadow can become multiply connected, strongly oblate, and the photon region does not hide the singularity, so it should be classified as a strong singularity.

show abstract

“…The recent publication of an image of a black hole at the center of our Galaxy [1] and Galaxy M87 [2] stimulates further interest in shadows and relativistic images of black holes as a tool for searching for new physics in the Cosmos. The shadows of black holes and images of accretion disks around them are now released in the radio and optical ranges and they are associated with the properties of null geodesics in strong gravitational fields [3][4][5][6][7][8][9][10]. The most important role in the mathematical understanding of shadows is played by the concept of characteristic photon surfaces [11][12][13][14][15][16][17][18][19][20][21] -timelike hypersurfaces, where bounded photon trajectories are lined up.…”

Section: Introductionmentioning

confidence: 99%

The geometry of massive particle surfaces

Kobialko¹,

Bogush²,

Gal’tsov³

2022

Preprint

View full text Add to dashboard Cite

We propose a generalization of Claudel, Virbhadra, and Ellis photon surfaces to the case of massive charged particles, considering a timelike hypersurface such that any worldline of a particle with mass m, electric charge q and fixed total energy E, initially touching it, will remain in this hypersurface forever. This definition does not directly appeal to the equations of motion, but instead make use of partially umbilic nature of the surface geometry. Such an approach should be especially useful in the case of non-integrable equations of motion. It may be applied in the theory of non-thin accretion discs, and also may serve a new tool for some general problems, such as uniqueness theorems, Penrose inequalities and hidden symmetries. The condition for the stability of the worldlines is derived, which reduces to differentiation along the flow of surfaces of a certain energy. We consider a number of examples of electrovacuum and dilaton solutions, find conditions for marginally stable orbits, regions of stable or unstable spherical orbits, stable and unstable photon surfaces, and solutions satisfying the no-force condition.

show abstract

Visible shapes of black holes M87* and SgrA*

Cited by 5 publications

References 75 publications

Shadow, lensing, quasinormal modes, greybody bounds and neutrino propagation by dyonic ModMax black holes

Shadow, lensing, quasinormal modes, greybody bounds and neutrino propagation by dyonic ModMax black holes

Photon surfaces, shadows and accretion disks in gravity with minimally coupled scalar field

The geometry of massive particle surfaces

Contact Info

Product

Resources

About