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- Arca Sedda, Manuel, et al.
(författare)
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The missing link in gravitational-wave astronomy A summary of discoveries waiting in the decihertz range
- 2021
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Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 51, s. 1427-1440
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Tidskriftsartikel (refereegranskat)abstract
- Since 2015 the gravitational-wave observations of LIGO and Virgo have transformed our understanding of compact-object binaries. In the years to come, ground-based gravitational-wave observatories such as LIGO, Virgo, and their successors will increase in sensitivity, discovering thousands of stellar-mass binaries. In the 2030s, the space-based LISA will provide gravitational-wave observations of massive black holes binaries. Between the similar to 10-10(3) Hz band of ground-based observatories and the similar to 10(-4)-10(- 1) Hz band of LISA lies the uncharted decihertz gravitational-wave band. We propose a Decihertz Observatory to study this frequency range, and to complement observations made by other detectors. Decihertz observatories are well suited to observation of intermediate-mass (similar to 10(2)-10(4)M(circle dot)) black holes; they will be able to detect stellar-mass binaries days to years before they merge, providing early warning of nearby binary neutron star mergers and measurements of the eccentricity of binary black holes, and they will enable new tests of general relativity and the Standard Model of particle physics. Here we summarise how a Decihertz Observatory could provide unique insights into how black holes form and evolve across cosmic time, improve prospects for both multimessenger astronomy and multiband gravitational-wave astronomy, and enable new probes of gravity, particle physics and cosmology.
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| 2. |
- Kuan, Hao Jui, et al.
(författare)
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Nonlinear evolution and nonuniqueness of scalarized neutron stars
- 2021
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 104:12
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Tidskriftsartikel (refereegranskat)abstract
- It was recently shown, that in a class of tensor-multiscalar theories of gravity with a nontrivial target space metric, there exist scalarized neutron star solutions. An important property of these compact objects is that the scalar charge is zero and therefore, the binary pulsar experiments can not impose constraints based on the absence of scalar dipole radiation. Moreover, the structure of the solutions is very complicated. For a fixed central energy density up to three neutron star solutions can exist - one general relativistic and two scalarized - which is quite different from the scalarization in other alternative theories of gravity. In the present paper we address the stability of these solutions using two independent approaches - solving the linearized radial perturbation equations and performing nonlinear simulations in spherical symmetry. The results show that the change of stability occurs at the maximum mass models and all solutions before that point are stable. This leads to the interesting consequence that there exists a stable part of the scalarized branch close to the bifurcation point where the mass of the star increases with the decrease of the central energy density.
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