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

Abstract

The need for a consistent quantum evolution for black holes has led to proposals that their semiclassical description is modified not just near the singularity, but at horizon or larger scales. If such modifications extend beyond the horizon, they influence regions accessible to distant observeration. Natural candidates for these modifications behave like metric fluctuations, with characteristic length and time scales set by the horizon radius. In this study, we investigate the possibility of using the Event Horizon Telescope to observe these effects, if they have a strength sufficient to make quantum evolution consistent with unitarity. We find that such quantum fluctuations can introduce a strong time dependence for the shape and size of the shadow that a black hole casts on its surrounding emission. For the black hole in the center of the Milky Way, detecting the rapid time variability of its shadow will require non-imaging timing techniques. However, for the much larger black hole in the center of the M87 galaxy, a variable black-hole shadow, if present with these parameters, would be readily observable in the individual snapshots that will be obtained by the Event Horizon Telescope.

Authors:

Giddings, Steven B. ^[1]; Psaltis, Dimitrios ^[2]

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+ Show Author Affiliations

1. Univ. of California, Santa Barbara, CA (United States)
2. Univ. of Arizona, Tucson, AZ (United States)

Publication Date:

2018-04-19

Research Org.:

Univ. of California, Santa Barbara, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25); Foundational Questions Institute; National Aeronautics and Space Administration (NASA)

OSTI Identifier:

1600760

Alternate Identifier(s):

OSTI ID: 1433749

Grant/Contract Number:  

SC0011702; FQXi-RFP-1507; NNX14AB48G; AST 1312034

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review D

Additional Journal Information:

Journal Volume: 97; Journal Issue: 8; Journal ID: ISSN 2470-0010

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; Quantum gravity; Astronomical black holes