Event Horizon Telescope observations as probes for quantum structure of astrophysical black holes

Giddings, Steven B.; Psaltis, Dimitrios

doi:10.1103/physrevd.97.084035

Cited by 80 publications

(78 citation statements)

References 62 publications

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“…The images used in our analysis in Section 7 measure the shape of the emitting region. In future work a similar analysis can be done using images from models that violate the no-hair theorem, where the photon ring/shadow shape can be highly prolate, oblate, or even amorphous (Broderick et al 2014;Giddings & Psaltis 2018).…”

Section: Implications For the Kerr Nature Of The Black Holementioning

confidence: 99%

First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

Akiyama

Alberdi

Alef

et al. 2019

ApJL

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We present measurements of the properties of the central radio source in M87 using Event Horizon Telescope data obtained during the 2017 campaign. We develop and fit geometric crescent models (asymmetric rings with interior brightness depressions) using two independent sampling algorithms that consider distinct representations of the visibility data. We show that the crescent family of models is statistically preferred over other comparably complex geometric models that we explore. We calibrate the geometric model parameters using general relativistic magnetohydrodynamic (GRMHD) models of the emission region and estimate physical properties of the source. We further fit images generated from GRMHD models directly to the data. We compare the derived emission region and black hole parameters from these analyses with those recovered from reconstructed images. There is a remarkable consistency among all methods and data sets. We find that >50% of the total flux at arcsecond scales comes from near the horizon, and that the emission is dramatically suppressed interior to this region by a factor >10, providing direct evidence of the predicted shadow of a black hole. Across all methods, we measure a crescent diameter of 42±3 μas and constrain its fractional width to be <0.5. Associating the crescent feature with the emission surrounding the black hole shadow, we infer an angular gravitational radius of GM/Dc 2 =3.8±0.4 μas. Folding in a distance measurement of -+ 16.8 Mpc 0.7 0.8 gives a black hole mass of =  ´ | | M M 6.5 0.2 0.7 10 stat sys 9. This measurement from lensed emission near the event horizon is consistent with the presence of a central Kerr black hole, as predicted by the general theory of relativity.

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Section: Implications For the Kerr Nature Of The Black Holementioning

confidence: 99%

First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

Akiyama

Alberdi

Alef

et al. 2019

ApJL

Self Cite

1,121

510

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“…If one assumes these fluctuations should lead to a minimal departure from Hawking's description of BH evolution, and in particular should not greatly alter the thermal spectrum of the BH emission [49] [48], the frequencies of the fluctuations should be of comparable to the thermal frequency, The period for Sgr A * is less than the EHT image scan time of several hours, making it hard to resolve such temporal fluctuation. This suggests the best sensitivity to such variation is from M87 observations.…”

Section: (B) Strong/coherent Scenariomentioning

confidence: 99%

Black holes in the quantum universe

Giddings

2019

Phil. Trans. R. Soc. A.

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A succinct summary is given of the problem of reconciling observation of black hole-like objects with quantum mechanics. If quantum black holes behave like subsystems, and also decay, their information must be transferred to their environments. Interactions that accomplish this with 'minimal' departure from a standard description are parameterized. Possible sensitivity of gravitational wave or very long baseline interferometric observations to these interactions is briefly outlined.

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“…GR predicts images with a particular structure, and specifically a "shadow" of the black hole with a bright "photon ring" just outside, resulting from gravitational lensing around the black hole. For example, in the case of soft quantum structure of [7], the necessary transfer of information may be accomplished by fluctuations with large magnitude, and simple models of such fluctuations can have significant impact on predicted images [15], including distortion of the photon ring and shadow, and the possibility of observable time dependence of the image. An open question is whether other versions of this soft scenario permit smaller, less-visible fluctuations, as newer work is suggesting [16].…”

Section: Oct 2017mentioning

confidence: 99%

Astronomical tests for quantum black hole structure

Giddings

2017

Nat Astron

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Quantum modifications to black holes on scales comparable to the horizon size, or even more radical physics, are apparently needed to reconcile the existence of black holes with the principles of quantum mechanics. This piece gives an overview of some possible observational tests for such departures from a classical description of black holes, via gravitational wave detection and very long baseline interferometry. (Invited comment for Nature Astronomy.) * giddings@ucsb.edu 1 arXiv:1703.03387v2 [gr-qc] Oct 2017Black holes present a profound challenge to our current foundations of physics, and an exciting era of astronomy is just opening where gravitational wave observation, represented by the recent LIGO detections [1], and very long baseline interferometry (VLBI), which is on the verge of resolving the immediate environs of super-massive black holes [2], may provide important hints about the new principles of physics needed.While the near-horizon region of a black hole is intrinsically interesting and has not been directly probed before, the conventional expectation has been that physics here, for astrophysical black holes, will be governed by classical general relativity (GR), and so the new observations should simply confirm GR's validity. After all, the spacetime curvature near such a horizona basic measure of the local gravity -would be tiny as compared to the values expected to be associated with any quantum behavior of spacetime.However, Hawking's discovery that black holes evaporate [3] has shaken this view to the core, with many quantum physicists now concluding that this result implies significant modifications to spacetime near black holes, and perhaps even further away. In fact, an attempt to give a logically consistent description of the evolution of black holes has lead to a foundational crisis in physics, which is apparently difficult to resolve without modifications to conventional physics not just at very short distance scales, as is expected in quantum gravity, but on macroscopic scales comparable to horizon radii of large black holes.The problem arises when considering information that falls into a black hole. In our most basic framework for currently established physics, quantum field theory, information cannot propagate faster than light, so then cannot escape. Therefore if a black hole evaporates away and disappears, as Hawking predicted, it destroys the information that fell in. This violates a bedrock principle of quantum mechanics, unitarity. Physicists have struggled with this issue for forty years [3], without finding a logically consistent resolution respecting current principles of physics. This problem appears to represent a profound conflict between the principles of relativity, the principles of quantum mechanics, and the principle of locality, which are the foundational principles of quantum field theory -our most fundamental current description of reality.Apparently something must give. Attempts to modify quantum mechanics have led to nonsensical conclusions, so many no...

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Event Horizon Telescope observations as probes for quantum structure of astrophysical black holes

Cited by 80 publications

References 62 publications

First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

Black holes in the quantum universe

Astronomical tests for quantum black hole structure

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