scholarly journals Effects of dark matter on the in-spiral properties of the binary neutron stars

2021 ◽  
Vol 507 (3) ◽  
pp. 4053-4060
Author(s):  
H C Das ◽  
Ankit Kumar ◽  
S K Patra
Keyword(s):  
Dark Matter ◽  
Neutron Star ◽  
Mean Field ◽  
Time Duration ◽  
Mean Field Model ◽  
Binary Neutron Star ◽  
Relativistic Mean Field ◽  
Orbital Phase ◽  
High Fraction ◽  
Spiral Phase

ABSTRACT Using the relativistic mean-field model, we calculate the properties of binary neutron star (BNS) in the in-spiral phase. Assuming the dark matter (DM) particles are accreted inside the neutron star (NS) due to its enormous gravitational field, the mass M, radius R, tidal deformability λ, and dimensionless tidal deformability Λ are calculated at different DM fractions. The value of M, R, λ, and Λ decreases with the increase of DM percentage inside the NS. The in-spiral phase properties of the BNS are explored within the post-Newtonian (PN) formalism, as it is suitable up to the last orbits in the in-spiral phase. We calculate the strain amplitude of the polarization waveform h+ and h×, (2,2) mode waveform h22, orbital phase Φ, frequency of the gravitational wave f, and PN parameter x with DM as an extra candidate inside the NS. The magnitude of f, Φ, and x are almost the same for all assumed forces; however, the in-spiral time duration in the last orbit is different. We find that the BNS with soft equation of state and a high fraction of DM sustains more time in their in-spiral phase. We suggest that one should take DM inside the NS when they modelling the in-spiral waveforms for the BNS systems.

scholarly journals Effects of dark matter on the nuclear and neutron star matter

2020 ◽  
Vol 495 (4) ◽  
pp. 4893-4903 ◽  
Author(s):  
H C Das ◽  
Ankit Kumar ◽  
Bharat Kumar ◽  
S K Biswal ◽  
Takashi Nakatsukasa ◽  
...  
Keyword(s):  
Dark Matter ◽  
Neutron Star ◽  
Symmetry Energy ◽  
Mean Field ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Equation Of States ◽  
Astrophysical Objects ◽  
Pure Neutron Matter ◽  
The Moment

ABSTRACT We study the dark matter (DM) effects on the nuclear matter (NM) parameters characterizing the equation of states of super dense neutron-rich nucleonic matter. The observables of the NM, i.e. incompressibility, symmetry energy and its higher order derivatives in the presence DM for symmetric and asymmetric NM are analysed with the help of an extended relativistic mean field model. The calculations are also extended to β-stable matter to explore the properties of the neutron star (NS). We analyse the DM effects on symmetric NM, pure neutron matter, and NS using NL3, G3, and IOPB-I forces. The binding energy per particle and pressure is calculated with and without considering the DM interaction with the NM systems. The influences of DM are also analysed on the symmetry energy and its different coefficients. The incompressibility and the skewness parameters are affected considerably due to the presence of DM in the NM medium. We extend the calculations to the NS and find its mass, radius and the moment of inertia for static and rotating NS with and without DM contribution. The mass of the rotating NS is considerably changing due to rapid rotation with the frequency in the mass-shedding limit. The effects of DM are found to be important for some of the NM parameters, which are crucial for the properties of astrophysical objects.

IMPACTS OF PARAMETERS ADJUSTMENT OF RELATIVISTIC MEAN FIELD MODEL ON NEUTRON STAR PROPERTIES

2011 ◽  
Vol 20 (05) ◽  
pp. 1271-1285 ◽  
Author(s):  
KASMUDIN ◽  
A. SULAKSONO
Keyword(s):  
Neutron Star ◽  
Reasonable Agreement ◽  
Field Model ◽  
Mean Field ◽  
Effective Field ◽  
Radiation Measurement ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
The Moment ◽  
Rmf Model

Analysis of the parameters adjustment effects in isovector as well as in isoscalar sectors of effective field based relativistic mean field (E-RMF) model in the symmetric nuclear matter and neutron-rich matter properties has been performed. The impacts of the adjustment on slowly rotating neutron star are systematically investigated. It is found that the mass–radius relation obtained from adjusted parameter set G2** is compatible not only with neutron stars masses from 4U 0614+09 and 4U 1636-536, but also with the ones from thermal radiation measurement in RX J1856 and with the radius range of canonical neutron star of X7 in 47 Tuc, respectively. It is also found that the moment inertia of PSR J073-3039A and the strain amplitude of gravitational wave at the Earth's vicinity of PSR J0437-4715 as predicted by the E-RMF parameter sets used are in reasonable agreement with the extracted constraints of these observations from isospin diffusion data.

scholarly journals Deconfinement of nonstrange hadronic matter with nucleons and Δ baryons to quark matter in neutron stars

2019 ◽  
Vol 28 (02) ◽  
pp. 1950040 ◽  
Author(s):  
Debashree Sen ◽  
T. K. Jha
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Quark Matter ◽  
Mean Field ◽  
Static Condition ◽  
Hadronic Matter ◽  
Chiral Model ◽  
Vector Coupling ◽  
Binary Neutron Star ◽  
Relativistic Mean Field

We explore the possibility of formation of [Formula: see text] baryons (1232[Formula: see text]MeV) in neutron star matter in an effective chiral model within the relativistic mean-field framework. With variation in delta-meson couplings, consistent with the constraints imposed on them, the resulting equation-of-state (EoS) is obtained and the neutron star properties are calculated for static and spherical configuration. Within the framework of our model, the critical densities of formation of [Formula: see text] and the properties of neutron stars (NS) are found to be very sensitive to the iso-vector coupling compared to the scalar or vector couplings. We revisit the [Formula: see text] puzzle and look for the possibility of phase transition from nonstrange hadronic matter (including nucleons and [Formula: see text]) to deconfined quark matter, based on QCD theories. The resultant hybrid star configurations satisfy the observational constraints on mass from the most massive pulsars PSR J1614-2230 and PSR J0348+0432 in static condition obtained with the general hydrostatic equilibrium based on GTR. Our radius estimates are well within the limits imposed from observational analysis of QLMBXs. The obtained values of [Formula: see text] are in agreement with the recent bounds specified from the observation of gravitational wave (GW170817) from binary neutron star merger. The constraint on baryonic mass from the study of binary system PSR J0737-3039 is also satisfied with our hybrid EoS.

scholarly journals Neutron star matter equation of state including d*-hexaquark degrees of freedom

2020 ◽  
Vol 638 ◽  
pp. A40
Author(s):  
A. Mantziris ◽  
A. Pastore ◽  
I. Vidaña ◽  
D. P. Watts ◽  
M. Bashkanov ◽  
...  
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Degrees Of Freedom ◽  
Field Model ◽  
Mean Field ◽  
The Other ◽  
Neutron Star Matter ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Walecka Model

We present the extension of a previous study where, assuming a simple free bosonic gas supplemented with a relativistic mean-field model to describe the pure nucleonic part of the equation of state, we studied the consequences that the first non-trivial hexaquark d*(2380) could have on the properties of neutron stars. Compared to that exploratory work, we employ a standard non-linear Walecka model including additional terms that describe the interaction of the d*(2380) di-baryon with the other particles of the system through the exchange of σ- and ω-meson fields. Our results show that the presence of the d*(2380) leads to maximum masses compatible with recent observations of ∼2 M⊙ millisecond pulsars if the interaction of the d*(2380) is slightly repulsive or the d*(2380) does not interact at all. An attractive interaction makes the equation of state too soft to be able to support a 2 M⊙ neutron star whereas an extremely repulsive one induces the collapse of the neutron star into a black hole as soon as the d*(2380) appears.

EVOLUTION OF SHELL STRUCTURE IN NUCLEI

2011 ◽  
Vol 20 (08) ◽  
pp. 1663-1675 ◽  
Author(s):  
A. BHAGWAT ◽  
Y. K. GAMBHIR
Keyword(s):  
Shell Structure ◽  
Crucial Role ◽  
Field Model ◽  
Mean Field ◽  
Mass Region ◽  
The Other ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Shell Closures ◽  
Low Mass

Systematic investigations of the pairing and two-neutron separation energies which play a crucial role in the evolution of shell structure in nuclei, are carried out within the framework of relativistic mean-field model. The shell closures are found to be robust, as expected, up to the lead region. New shell closures appear in low mass region. In the superheavy region, on the other hand, it is found that the shell closures are not as robust, and they depend on the particular combinations of neutron and proton numbers. Effect of deformation on the shell structure is found to be marginal.

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