Tidal Love number of neutron stars with conformal coupling

Hamza Boumaza

doi:10.1103/physrevd.104.084098

Love in extrema ratio

International Journal of Modern Physics D ◽

10.1142/s0218271819440012 ◽

2019 ◽

Vol 28 (14) ◽

pp. 1944001 ◽

Cited By ~ 9

Author(s):

Paolo Pani ◽

Andrea Maselli

Keyword(s):

Black Hole ◽

Neutron Stars ◽

Leading Order ◽

Mass Ratio ◽

Love Number ◽

Space Antenna ◽

Central Object ◽

Love Numbers ◽

Ratio Limit ◽

Laser Interferometric

The tidal deformability of a self-gravitating object leaves an imprint on the gravitational-wave signal of an inspiral which is paramount to measure the internal structure of the binary components. We unveil here a surprisingly unnoticed effect: in the extreme mass-ratio limit the tidal Love number of the central object (i.e. the quadrupole moment induced by the tidal field of its companion) affects the gravitational waveform at the leading order in the mass ratio. This effect acts as a magnifying glass for the tidal deformability of supermassive objects but was so far neglected, probably because the tidal Love numbers of a black hole (the most natural candidate for a compact supermassive object) are identically zero. We argue that extreme mass-ratio inspirals detectable by the future laser interferometric space antenna (LISA) mission might place constraints on the tidal Love numbers of the central object which are roughly eight orders of magnitude more stringent than current ones on neutron stars, potentially probing all models of black hole mimickers proposed so far.

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Gravitational wave signatures of highly magnetized neutron stars

The European Physical Journal C ◽

10.1140/epjc/s10052-020-08705-1 ◽

2020 ◽

Vol 80 (12) ◽

Author(s):

Cesar V. Flores ◽

Luiz L. Lopes ◽

Luis B. Castro ◽

Débora P. Menezes

Keyword(s):

Magnetic Fields ◽

Neutron Stars ◽

Gravitational Wave ◽

Field Approximation ◽

Love Number ◽

Strong Magnetic Fields ◽

Chaotic Field ◽

Quasi Normal Mode ◽

Low Mass ◽

The Magnetic Field

AbstractMotivated by the recent gravitational wave detection by the LIGO–VIRGO observatories, we study the Love number and dimensionless tidal polarizability of highly magnetized stars. We also investigate the fundamental quasi-normal mode of neutron stars subject to high magnetic fields. To perform our calculations we use the chaotic field approximation and consider both nucleonic and hyperonic stars. As far as the fundamental mode is concerned, we conclude that the role played by the constitution of the stars is far more relevant than the intensity of the magnetic field, and if massive stars are considered, the ones constituted by nucleons only present frequencies somewhat lower than the ones with hyperonic cores. This feature that can be used to point out the real internal structure of neutron stars. Moreover, our studies clearly indicate that strong magnetic fields play a crucial role in the deformability of low mass neutron stars, with possible consequences on the interpretation of the detected gravitational waves signatures.

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Constraints on neutron stars equation of state using the tidal deformability derived from BNS mergers

HNPS Proceedings ◽

10.12681/hnps.2989 ◽

2020 ◽

Vol 27 ◽

pp. 95

Author(s):

Alkiviadis Kanakis-Pegios ◽

Charalampos Moustakidis

Keyword(s):

Neutron Star ◽

Equation Of State ◽

Binary System ◽

Neutron Stars ◽

Effective Mass ◽

Lower Limit ◽

Mathematical Formalism ◽

Love Number ◽

Binary Neutron Star ◽

Upper Limit

The purpose of this work is the study of neutron stars (NS) equation of state (EOS) using constraints on tidal deformability derived from observation of binary neutron star (BNS) mergers, such as GW170817. The mathematical formalism is introduced, and then for a variety of EOS the system is solved numerically, allowing us to determine the mass, the radius, the tidal love number and the tidal deformability of the NS, each one of them unique for each EOS. Moreover, for a fixed value of chirp mass under the assumption that m2<m1 (where m1 is the heavier component mass of BNS system), the effective (mass-weighted) tidal deformability of the binary system is determined for each EOS. We consider both an upper limit (GW170817) and a lower limit (AT2017gfo) for the effective tidal deformability. Also, we construct the Λ1-Λ2 space and we compare the behavior of EOS with the most recent LIGO’s data. We found out that the most EOS models give values for the effective tidal deformability less than the upper limit and that the most stiff EOS are excluded.

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