EHT Constraint on the Ultralight Scalar Hair of the M87 Supermassive Black Hole

Cunha, Pedro V. P.; Herdeiro, Carlos; Radu, Eugen

doi:10.3390/universe5120220

Cited by 123 publications

(76 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One can ask if the Hamilton-Jacobi equation for the Hamiltonian (44) is separable in a generic spacetime obtained through the MNJA. In order to answer this question, we start applying the Hamilton-Jacobi equation (35) to the Hamiltonian (44), using that the Jacobi action is given by Eq. (38).…”

Section: Hamilton-jacobi Equation In Rotating Spacetime Obtained mentioning

confidence: 99%

Spinning black holes with a separable Hamilton–Jacobi equation from a modified Newman–Janis algorithm

et al. 2020

View full text Add to dashboard Cite

Obtaining solutions of the Einstein field equations describing spinning compact bodies is typically challenging. The Newman–Janis algorithm provides a procedure to obtain rotating spacetimes from a static, spherically symmetric, seed metric. It is not guaranteed, however, that the resulting rotating spacetime solves the same field equations as the seed. Moreover, the former may not be circular, and thus expressible in Boyer–Lindquist-like coordinates. Amongst the variations of the original procedure, a modified Newman–Janis algorithm (MNJA) has been proposed that, by construction, originates a circular, spinning spacetime, expressible in Boyer–Lindquist-like coordinates. As a down side, the procedure introduces an ambiguity, that requires extra assumptions on the matter content of the model. In this paper we observe that the rotating spacetimes obtained through the MNJA always admit separability of the Hamilton–Jacobi equation for the case of null geodesics, in which case, moreover, the aforementioned ambiguity has no impact, since it amounts to an overall metric conformal factor. We also show that the Hamilton–Jacobi equation for light rays propagating in a plasma admits separability if the plasma frequency obeys a certain constraint. As an illustration, we compute the shadow and lensing of some spinning black holes obtained by the MNJA.

show abstract

Section: Hamilton-jacobi Equation In Rotating Spacetime Obtained mentioning

confidence: 99%

Spinning black holes with a separable Hamilton–Jacobi equation from a modified Newman–Janis algorithm

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Thus, with high precision observation in the future, it is possible to select out the theory describing correctly gravity in nature through detecting black hole shadows. Moreover, black hole shadows have also been treated as a potential tool to study the possibility of constraining black hole parameters and extra dimension size [28,29], and to probe some fundamental physics issues including dark matter [30][31][32][33][34] and the equivalence principle [35]. The main purpose of this paper is to study the shadow of a rotating non-stealth black hole in quadratic DHOST theories and to see what new features exist in the shadow for this disformed black hole.…”

Section: Introductionmentioning

confidence: 99%

Shadow of a disformal Kerr black hole in quadratic degenerate higher-order scalar–tensor theories

2020

View full text Add to dashboard Cite

We have studied the shadow of a disformal Kerr black hole with an extra deformation parameter, which belongs to non-stealth rotating solutions in quadratic degenerate higher-order scalar–tensor (DHOST) theory. Our result show that the size of the shadow increases with the deformation parameter for the black hole with arbitrary spin parameter. However, the effect of the deformation parameter on the shadow shape depends heavily on the spin parameter of black hole and the sign of the deformation parameter. The change of the shadow shape becomes more distinct for the black hole with the more quickly rotation and the more negative deformation parameter. Especially, for the near-extreme black hole with negative deformation parameter, there exist a “pedicel”-like structure appeared in the shadow, which increases with the absolute value of deformation parameter. The eyebrow-like shadow and the self-similar fractal structures also appear in the shadow for the disformal Kerr black hole in DHOST theory. These features in the black hole shadow originating from the scalar field could help us to understand the non-stealth disformal Kerr black hole and quadratic DHOST theory.

show abstract

“…While a direct spin measurement is still not available, M87 has been suggested to have a large spin [81,82]. A putative measurement χ M87 ≳ 0.2 would constrain the mass range m b ∼ 10 −20 − 10 −21 eV [83][84][85]. If the largest known supermassive BHs with M ≃ 2 × 10 10 M ⊙ [86,87] were confirmed to have nonzero spin [88], we could get even more stringent bounds.…”

mentioning

confidence: 98%

Black Hole Superradiant Instability from Ultralight Spin-2 Fields

2020

View full text Add to dashboard Cite

Ultralight bosonic fields are compelling dark-matter candidates and arise in a variety of beyond standard model scenarios. These fields can tap energy and angular momentum from spinning black holes through superradiant instabilities, during which a macroscopic bosonic condensate develops around the black hole. Striking features of this phenomenon include gaps in the spin-mass distribution of astrophysical black holes and a continuous gravitational-wave (GW) signal emitted by the condensate. So far these processes have been studied in great detail for scalar fields and, more recently, for vector fields. Here we take an important step forward in the black hole superradiance program by computing, analytically, the instability timescale, direct GW emission, and stochastic background, in the case of massive tensor (i.e., spin-2) fields. Our analysis is valid for any black hole spin and for small boson masses. The instability of massive spin-2 fields shares some properties with the scalar and vector cases, but its phenomenology is much richer, for example, there exist multiple modes with comparable instability timescales, and the dominant GW signal is hexadecapolar rather than quadrupolar. Electromagnetic and GW observations of spinning black holes in the mass range M ∈ ð1; 10 10 Þ M ⊙ can constrain the mass of a putative spin-2 field in the range 10 −22 ≲ m b c 2 =eV ≲ 10 −10. For 10 −17 ≲ m b c 2 =eV ≲ 10 −15 , the space mission LISA could detect the continuous GW signal for sources at redshift z ¼ 20, or even larger.

show abstract

EHT Constraint on the Ultralight Scalar Hair of the M87 Supermassive Black Hole

Cited by 123 publications

References 59 publications

Spinning black holes with a separable Hamilton–Jacobi equation from a modified Newman–Janis algorithm

Spinning black holes with a separable Hamilton–Jacobi equation from a modified Newman–Janis algorithm

Shadow of a disformal Kerr black hole in quadratic degenerate higher-order scalar–tensor theories

Black Hole Superradiant Instability from Ultralight Spin-2 Fields

Contact Info

Product

Resources

About