Maximum mass of compact stars from gravitational wave events with finite-temperature equations of state

Khadkikar, Sanika; Raduta, Adriana R.; Oertel, Micaela; Sedrakian, Armen

doi:10.48550/arxiv.2102.00988

Cited by 6 publications

(7 citation statements)

References 102 publications

(229 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Neutron stars (NSs) are currently in the epicenter of scientific interest, since they are truly laboratories in the sky, for many scientific purposes, like nuclear physics [1][2][3][4][5][6][7][8][9][10][11], particle physics [12][13][14][15] and theoretical astrophysics [16][17][18][19][20][21][22][23]. NSs have been thoroughly studied in the last 40 years, and the latest LIGO-Virgo astronomical observations of gravitational waves emitted from merging of NSs, makes the once but long ago theoretical dream of understanding how NSs are composed, a scientifically strong and overwhelming reality.…”

Section: Introductionmentioning

confidence: 99%

Causal Limit of Neutron Star Maximum Mass in $f(R)$ Gravity in View of GW190814

Astashenok,

Capozziello,

Odintsov

et al. 2021

Preprint

View full text Add to dashboard Cite

We investigate the causal limit of maximum mass for stars in the framework of f (R) gravity. We choose a causal equation of state, with variable speed of sound, and with the transition density and pressure corresponding to the SLy equation of state. The transition density is chosen to be equal to twice the saturation density ρt ∼ 2ρ0, and also the analysis is performed for the transition density, chosen to be equal to the saturation density ρt ∼ ρ0. We examine numerically the combined effect of the stiff causal equation of state and of the sound speed on the maximum mass of static neutron stars, in the context of Jordan frame of f (R) gravity. This yields the most extreme upper bound for neutron star masses in the context of extended gravity. As we will evince for the case of R 2 model, the upper causal mass limit lies within, but not deeply in, the mass-gap region, and is marginally the same with the general relativistic causal maximum mass, indicating that the ∼ 3M general relativistic limit is respected. In view of the modified gravity perspective for the secondary component of the GW190814 event, we also discuss the strange star possibility. Using several well established facts for neutron star physics and the Occam's razor approach, although the strange star is exciting, for the moment, it remains a possibility for describing the secondary component of GW190814. We underpin the fact that the secondary component of the compact binary GW190814 is probably a neutron star, a black hole or even a rapidly rotating neutron star, but not a strange star. We also discuss, in general, the potential role of the extended gravity description for the binary merging.

show abstract

Section: Introductionmentioning

confidence: 99%

Causal Limit of Neutron Star Maximum Mass in $f(R)$ Gravity in View of GW190814

Astashenok,

Capozziello,

Odintsov

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…On the other hand, the possibility for GW190814's secondary as a neutron star can be accomplished by: 1) Choose/construct stiff EOSs having the maximum mass larger than 2.5 M [131][132][133][134][135][136][137][138][139][140][141] ; 2) Consider effects of fast rotations which can increases the maximum mass by about 20% when a star rotates at the Kepler frequency (the maximum frequency at which the gravitational attraction is still sufficient to keep matter bound to the pulsar surface) [35,36,129,130,136,[142][143][144][145][146][147][148]; 3) Consider other effects/models that can modify the maximum mass of neutron star, such as magnetic field [138], twin star [149], two family compact star [132], finite-temperature [144], antikaon condensation [150], or net electric charge [134], etc.…”

Section: Is Gw190814's Secondary a Superfast And Supermassive Neutron...mentioning

confidence: 99%

“…This is not the case for pure quark stars, which can easily reach 2.5 M and still possess approximately the same amount of baryons as stable non-rotating stars. Khadkikar et al [144] selected 11 EOSs from relativistic density functional theories, Skyrme functionals, and an empirical extension of a variational microscopic model. Hyperons are also included in their discussions.…”

Section: Is Gw190814's Secondary a Superfast And Supermassive Neutron...mentioning

confidence: 99%

Progress in Constraining Nuclear Symmetry Energy Using Neutron Star Observables Since GW170817

Li,

Cai,

Xie

et al. 2021

Preprint

View full text Add to dashboard Cite

The density dependence of nuclear symmetry energy is among the most uncertain parts of the Equation of State (EOS) of dense neutron-rich nuclear matter. It is currently poorly known especially at suprasaturation densities partially because of our poor knowledge about isovector nuclear interactions at short distances. Because of its broad impacts on many interesting issues, to pin down the density dependence of nuclear symmetry energy has been a longstanding and shared goal of both astrophysics and nuclear physics. New observational data of neutron stars including their masses, radii, and tidal deformations since GW170817 have helped improve our knowledge about nuclear symmetry energy especially at high densities. Based on various model analyses of these new data by many people in the nuclear astrophysics community, while our brief review might be incomplete and biased unintentionally, we have learned particularly: (1) The slope parameter L of nuclear symmetry energy at saturation density ρ 0 of nuclear matter from 24 new analyses of neutron star observables is about L ≈ 57.7 ± 19 MeV at 68% confidence level consistent with its fiducial value from surveys of over 50 earlier analyses of both terrestrial and astrophysical data within error bars, (2) The curvature K sym of nuclear symmetry energy at ρ 0 from 16 new analyses of neutron star observables is about K sym ≈ −107 ± 88 MeV at 68% confidence level in very good agreement with the systematics of earlier analyses, (3) The magnitude of nuclear symmetry energy at 2ρ 0 , i.e. E sym (2ρ 0 ) ≈ 51 ± 13 MeV at 68% confidence level, has been extracted from 9 new analyses of neutron star observables consistent with results from earlier analyses of heavy-ion reactions and the latest predictions of the state-of-the-art nuclear many-body theories, (4) while the available data from canonical neutron stars do not provide tight constraints on nuclear symmetry energy at densities above about 2ρ 0 , the lower radius boundary R 2.01 = 12.2 km from NICER's very recent observation of PSR J0740+6620 of mass 2.08 ± 0.07 M and radius R = 12.2 − 16.3 km at 68% confidence level sets a tight lower limit for nuclear symmetry energy at densities above 2ρ 0 , (5) Bayesian inferences of nuclear symmetry energy using models encapsulating a first-order hadron-quark phase transition from observables of canonical neutron stars indicate that the phase transition shifts appreciably both the L and K sym to higher values but with larger uncertainties compared to analyses assuming no such phase transition, (6) The high-density behavior of nuclear symmetry energy affects significantly the minimum frequency necessary to rotationally support GW190814's secondary component of mass (2.50-2.67) M as the fastest and most massive pulsar discovered so far. Overall, thanks to the hard work of many people in the astrophysics and nuclear physics community, new data of neutron star observations since the discovery of GW170817 have enriched significantly our knowledge about the symmetry energy of dense neutron-ric...

show abstract

“…Neutron stars (NS) have developed to be in the epicenter of current scientific interest, since they are literally laboratories in the cosmos, for many scientific disciplines like nuclear [1][2][3][4][5][6][7][8][9][10][11] and high energy particle physics [12][13][14][15], modified gravity [16][17][18][19][20][21][22] and astrophysics [23][24][25][26][27][28][29][30]. Nearly fifty years after the first observation of a NS by Jocelyn Bell, the observational aspects of neutron stars have been developed quite significantly, with the LIGO-Virgo collaboration being the "tip of the spear" in observing and analyzing gravitational waves emerging from NSs and black holes processes.…”

Section: Introductionmentioning

confidence: 99%

Neutron Stars in Scalar-tensor Gravity with Quartic Order Scalar Potential

Odintsov,

Oikonomou

2021

Preprint

View full text Add to dashboard Cite

The Higgs scalar which is the only experimentally verified fundamental cosmological scalar, is also known to produce a viable inflationary phenomenology. In this work we investigate the effects of the Higgs model on static neutron stars. Particularly we derive the Einstein frame Tolman-Oppenheimer-Volkoff equations, and by numerically integrating them for both the interior and the exterior of the neutron star, using a double shooting python 3 based numerical code, we extract the masses and radii of the neutron stars, along with the several other related physical quantities of interest. With regard to the equation of state for the neutron star, we use a piecewise polytropic equation of state with the central part being SLy, APR or the WFF1 equations of state. The resulting M −R graphs are compatible with the observational bounds imposed by the GW170817 event which require the radius of a static M ∼ 1.6M neutron star to be larger than R = 10.68 +15 −0.04 km and the radius of a static neutron star corresponding to the maximum mass of the star to be larger than R = 9.6 +0.14 −0.03 km. Moreover, the WFF1 EoS, which was excluded for static neutron stars in the context of general relativity, for the Higgs neutron star model provides realistic results compatible with the GW170817 event.

show abstract

Maximum mass of compact stars from gravitational wave events with finite-temperature equations of state

Cited by 6 publications

References 102 publications

Causal Limit of Neutron Star Maximum Mass in $f(R)$ Gravity in View of GW190814

Causal Limit of Neutron Star Maximum Mass in $f(R)$ Gravity in View of GW190814

Progress in Constraining Nuclear Symmetry Energy Using Neutron Star Observables Since GW170817

Neutron Stars in Scalar-tensor Gravity with Quartic Order Scalar Potential

Contact Info

Product

Resources

About