2000) taken by the Event Horizon Telescope (EHT) Collaboration ( The Event Horizon Telescope Collaboration 2019a) have opened a new era, by extending tests of general relativity into the strong gravity regime. 2021), and the image of a black hole shadow ( Falcke et al. 2016), radio pulsar observations ( Wex & Kramer 2020 Kramer et al. In the last decade, the direct detection of gravitational waves emitted during the coalescence of binary black hole systems ( Abbott et al. Its predictions have been confirmed in a vast number of experiments ranging from fundamental tests of the equivalence principle over the bending of light, the perihelion advance of mercury, and the Shapiro time delay, up to stellar system tests conducted within binary pulsar systems ( Will 2014). General relativity constitutes the benchmark for describing gravitational phenomena. Subscribe to A&A to support open access publication. This article is published in open access under the Subscribe to Open model. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Our work constitutes the first step towards bounding the phase space of black-hole-type solutions with a clear quantum gravity interpretation based on observational data. On this basis, we argue that it is the brightness within the shadow region that constrains the phase space of solutions. We then carry out an analytic analysis of observable signatures accessible to the Event Horizon Telescope, comprising the size of the black hole shadow as well as the radiation emitted by infalling matter. Characteristically, the deformed solutions follow the Schwarzschild solution up outside of the photon sphere, while they differ substantially close to the center of gravity. We find that the Schwarzschild geometry is embedded in a rich solution space comprising horizonless, naked singularities and wormhole solutions. In this work, we construct the associated phase space of static, spherically symmetric, and asymptotically flat spacetimes. Quadratic gravity constitutes a prototypical example of a perturbatively renormalizable quantum theory of the gravitational interactions. Wondrak 2 ,3 and Heino Falcke 2ĭepartment of High Energy Physics/IMAPP, Radboud University, PO Box 9010 6500 GL Nijmegen, The Netherlandsĭepartment of Astrophysics/IMAPP, Radboud University, PO Box 9010 6500 GL Nijmegen, The NetherlandsĮ-mail: of Mathematics/IMAPP, Radboud University, PO Box 9010 6500 GL Nijmegen, The Netherlands Jesse Daas 1, Kolja Kuijpers 1, Frank Saueressig 1, Michael F. Astronomical objects: linking to databases.Including author names using non-Roman alphabets.Suggested resources for more tips on language editing in the sciences Punctuation and style concerns regarding equations, figures, tables, and footnotes Meridian - The vertical circle which passes through the north and south points.Vertical Circle - Any great circle which passes through the zenith.South Point - Point on horizon in direction of geographical south.North Point - Point on horizon in direction of geographical north.Nadir - Point on celestial sphere directly beneath observer.Zenith - Point on celestial sphere directly overhead.Read over the list of terms and definitions in the list and/or mouse over the terms in the image to view their definitions. Or, when the Sun passes from one side of the meridian to the other, you can talk about the Sun "transiting the meridian." These terms and their meanings are illustrated using the following two diagrams. For example, you can refer to the altitude of the Sun. The vocabulary you will encounter in this lesson includes:Īll of these terms are used to describe the location or behavior of objects in the sky. In our case, though, I'm going to break my own rule so that we can start discussing the sky immediately and make sure that we agree on the meaning of these terms. Normally, I advocate for discussing vocabulary in the context of a lesson, instead of presenting it like this to begin the lesson. In this lesson, we will be using some vocabulary that may be either unfamiliar or may be used differently, in an astronomical context, from your usual usage. If you want to complete some additional reading beyond what is in our Lesson 1 pages, I recommend:
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |