Special Issue "Gravitational Radiation in Cosmological Spacetimes"

A special issue of Universe (ISSN 2218-1997). This special issue belongs to the section "Gravitation".

Deadline for manuscript submissions: 31 July 2022 | Viewed by 913

Special Issue Editor

Dr. B.P. Bonga (Béatrice)
E-Mail Website
Guest Editor
Institute for Mathematics, Astrophysics and Particle Physics, Radboud University, 6525 AJ Nijmegen, The Netherlands
Interests: gravitational wave theory; resonance effects in neutron stars and black hole spacetimes; gravitational radiation in cosmological spacetimes; early universe cosmology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Gravitational waves are now observed by LIGO-Virgo a few times a month, and it is difficult to imagine that in the early days of General Relativity, their physical reality was debated. However, many prominent scientists including Einstein himself questioned whether gravitational waves truly exist in nature. Theoretical developments to study gravitational waves generated by compact sources such as binary black holes in asymptotically flat spacetimes and the observation of the orbital decay in the Hulse–Taylor binary in the 1970s put an end to this debate. These theoretical advances also allowed the study of the nonlinear effects inherent in General Relativity by studying radiation at future null infinity. Despite these amazing advancements on the theoretical side, gravitational waves in cosmological spacetimes are still mostly studied in the linearized setting. With the increasing sensitivity of gravitational wave observatories, we will observe radiation emitted by sources increasingly far away, and therefore, cosmological effects will become important. Consequently, a fundamental understanding beyond geometrics optics approximation in the linearized setting is needed.

This Special Issue aims to collect and act as a catalyzer for progress in our understanding of gravitational waves emitted by compact sources in cosmological spacetimes—both with and without a cosmological constant.

Dr. B.P. Bonga (Béatrice)
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Universe is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • gravitational waves
  • cosmological constant
  • FLRW spacetimes
  • de Sitter spacetime
  • asymptotics
  • null infinity

Published Papers (2 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Article
Lensing Magnification Seen by Gravitational Wave Detectors
Universe 2022, 8(1), 19; https://doi.org/10.3390/universe8010019 - 30 Dec 2021
Viewed by 274
Abstract
In this paper, we studied the gravitational lensing of gravitational wave events. The probability that an observed gravitational wave source has been (de-)amplified by a given amount is a detector-dependent quantity which depends on different ingredients: the lens distribution, the underlying distribution of [...] Read more.
In this paper, we studied the gravitational lensing of gravitational wave events. The probability that an observed gravitational wave source has been (de-)amplified by a given amount is a detector-dependent quantity which depends on different ingredients: the lens distribution, the underlying distribution of sources and the detector sensitivity. The main objective of the present work was to introduce a semi-analytic approach to study the distribution of the magnification of a given source population observed with a given detector. The advantage of this approach is that each ingredient can be individually varied and tested. We computed the expected magnification as both a function of redshift and of the observedsource luminosity distance, which is the only quantity one can access via observation in the absence of an electromagnetic counterpart. As a case study, we then focus on the LIGO/Virgo network and on strong lensing (μ>1). Full article
(This article belongs to the Special Issue Gravitational Radiation in Cosmological Spacetimes)
Show Figures

Figure 1

Article
Cherenkov Gravitational Radiation during the Radiation Era
Universe 2021, 7(11), 437; https://doi.org/10.3390/universe7110437 - 15 Nov 2021
Cited by 1 | Viewed by 353
Abstract
Cherenkov radiation may occur whenever the source is moving faster than the waves it generates. In a radiation dominated universe, with equation-of-state w=1/3, we have recently shown that the Bardeen scalar-metric perturbations contribute to the linearized Weyl tensor [...] Read more.
Cherenkov radiation may occur whenever the source is moving faster than the waves it generates. In a radiation dominated universe, with equation-of-state w=1/3, we have recently shown that the Bardeen scalar-metric perturbations contribute to the linearized Weyl tensor in such a manner that its wavefront propagates at acoustic speed w=1/3. In this work, we explicitly compute the shape of the Bardeen Cherenkov cone and wedge generated respectively by a supersonic point mass (approximating a primordial black hole) and a straight Nambu-Goto wire (approximating a cosmic string) moving perpendicular to its length. When the black hole or cosmic string is moving at ultra-relativistic speeds, we also calculate explicitly the sudden surge of scalar-metric induced tidal forces on a pair of test particles due to the passing Cherenkov shock wave. These forces can stretch or compress, depending on the orientation of the masses relative to the shock front’s normal. Full article
(This article belongs to the Special Issue Gravitational Radiation in Cosmological Spacetimes)
Show Figures

Figure 1

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Gravitational radiation with non-negative cosmological constant
Authors: José M M Senovilla
Affiliation: Departamento de Física, Universidad del País Vasco UPV/EHU, Apartado 48080, Bilbao, Spain; EHU Quantum Center, Universitu of the Basque Country UPV/EHU
Abstract: The existence of gravitational radiation arriving at null infinity J+ –i.e. escaping from the physical system– is addressed in the presence of a non-negative cosmological constant. The case with vanishing cosmological constant is well understood and relies on the properties of the News tensor field (or the News function) defined at infinity. The situation is drastically different when Lambda >0 where there is no known notion of ‘News’ with similar good properties. In this paper both situations are considered jointly from a tidal point of view, that is, taking into account the strength (or energy) of the curvature tensors. This leads to a novel characterization of gravitational radiation valid for the general case that has been proven to be equivalent, when Lambda = 0, to the standard one based on News. The implications of this result (on asymptotic symmetries, peeling theorem, balance laws, and others) are analyzed in some detail when Lambda > 0. Several explicit illustrative examples are provided.

Back to TopTop