Article
Astronomy & Astrophysics
Hristijan Kochankovski, Angels Ramos, Laura Tolos
Summary: The FSU2H equation-of-state model is extended to finite temperature and it is found that temperature has a stronger effect on thermodynamical observables and the composition of neutron star cores when considering hyperonic degrees of freedom. The widely used Gamma law is not appropriate to reproduce the true thermal effects, especially when hyperons become abundant in the neutron star core. Simple parametrizations of the thermal index for nucleonic and hyperonic beta-stable neutrino-free matter are provided to make finite temperature equations of state easily accessible.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
J. R. Stone, V Dexheimer, P. A. M. Guichon, A. W. Thomas, S. Typel
Summary: A new equation of state for cold and hot hyperonic matter has been developed in the context of the quark-meson-coupling model, yielding results compatible with existing nuclear physics constraints and astrophysical observations. The study explores the presence of hyperons in proto-neutron stars and neutron stars, as well as the nucleon-hyperon phase transition. Results show a correlation between hyperon presence and increasing temperature and density, with implications for understanding neutron star merger remnants.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Peter Shternin, Isaac Vidana
Summary: The study reveals that in dense matter, neutrons have a more significant contribution to transport coefficients compared to other baryons. Due to the onset of Sigma(-), which results in the deleptonization of the neutron star core, neutrons also dominate shear viscosity in the high density region.
Article
Astronomy & Astrophysics
Vittorio De Falco, Maciek Wielgus
Summary: This study further explores the three-dimensional general relativistic Poynting-Robertson effect in the motion around compact objects, discussing the effects of radiation pressure and radiation drag force, investigating the properties of critical hypersurfaces, and demonstrating how this model can be applied to radiation phenomena near neutron stars.
Article
Physics, Nuclear
Bikram Keshari Pradhan, Debarati Chatterjee, Michael Lanoye, Prashanth Jaikumar
Summary: We present a systematic study extending recent results on f-mode oscillations in neutron stars containing hyperons to linearized general relativity. By employing a relativistic mean-field model, we find that the Cowling approximation can overestimate the f-mode frequency of neutron stars. We also derive updated empirical relations for gravitational wave asteroseismology and provide estimates for the detectability of f-modes in a transient burst of gravitational waves from isolated hyperonic stars.
Article
Astronomy & Astrophysics
Morgane Fortin, Adriana R. Raduta, Sidney Avancini, Constanca Providencia
Summary: The study utilized a set of unified relativistic mean-field equations of state to investigate the thermal evolution of nonmagnetized and nonrotating spherically-symmetric isolated and accreting neutron stars, and found that different equations of state and proton superfluidity properties can impact the results.
Article
Physics, Nuclear
T. F. Motta, P. A. M. Guichon, A. W. Thomas
Summary: Building upon recent model independent constraints on the equation of state of dense baryonic matter, we have shown using the quark-meson coupling model that the equation of state is consistent with these constraints when hyperons are allowed to appear in dense matter in beta-equilibrium. Therefore, while the possibility of quark matter and hyperons in the cores of massive neutron stars cannot be ruled out, the available constraints are also compatible with the presence of hyperons.
Article
Astronomy & Astrophysics
Norman Khan, Matthew J. Middleton, Grzegorz Wiktorowicz, Thomas Dauser, Timothy P. Roberts, Joern Wilms
Summary: The discovery of neutron stars powering ultraluminous X-ray sources raises questions about the underlying population, with this paper incorporating a model to estimate the relative number of visible ULXs based on various factors such as the abundance of black holes or neutron stars. By comparing data from XMM-Newton and predicting the impact of the eROSITA all-sky survey, the study aims to constrain the underlying demographic and provide insights into the nature of these phenomena.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Daniel Barta
Summary: This research paper investigates the effect of viscosity and thermal conductivity on the radial oscillation of non-rotating neutron stars in the high nuclear density regime. The study provides valuable information for imposing constraints on realistic equations of state models and has practical applications for asteroseismology of compact objects.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Physics, Nuclear
Fu Ma, Chen Wu, Wenjun Guo
Summary: In this study, we investigate the equation of state of dense baryon matter using the relativistic mean-field model. We incorporate the Delta(1232) isobars in the IUFSU model with hyperons and consider the potential condensation of kaon mesons. It is found that the presence of Delta resonances is necessary for the stability of a massive neutron star, and the addition of Delta resonance leads to a softer equation of state in the low density region, consistent with observational data.
Article
Physics, Nuclear
Matteo Vorabbi, Michael Gennari, Paolo Finelli, Carlotta Giusti, Petr Navratil, Ruprecht Machleidt
Summary: The purpose of this study is to introduce the 3N force into the dynamic part of the OP for a more consistent calculation. Through an approximate treatment of the 3N force in the model, the major contribution of the two-pion exchange term to the 3N force is identified, and the convergence of results at the next-to-next-to-next-to-leading-order is confirmed.
Article
Astronomy & Astrophysics
Irina Dvorkin, Frederic Daigne, Stephane Goriely, Elisabeth Vangioni, Joseph Silk
Summary: This study investigates the enrichment of the interstellar medium with r-process elements produced in binary neutron star mergers using a semi-analytic model. By simulating the dispersion of these elements in the ISM through a turbulent mixing scheme, the study shows that the observed abundances in Milky Way stars, especially the scatter at low metallicities, can be entirely explained by BNS mergers. The results suggest that BNS mergers could be the dominant source of r-process elements in the Galaxy.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
L. Jens Papenfort, Elias R. Most, Samuel Tootle, Luciano Rezzolla
Summary: Simulations of high-spin binary neutron-star mergers reveal significant differences compared to equal-mass, irrotational systems in terms of remnant lifetime, dynamical ejecta, remnant disc masses, secular ejecta, and bulk kilonova properties.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
M. C. Rodriguez, Ignacio F. Ranea-Sandoval, C. Chirenti, D. Radice
Summary: In this study, three different classification methods were applied to investigate PNS non-radial oscillation modes. It was found that the Cowling classification was inconsistent in the early stages of PNS evolution, but the GCN and CBMP provided complementary information for understanding the mode evolution. Several avoided crossings were observed in the GCN, while the CBMP tracked the modes across the avoided crossings. The strongest emission of GWs by the PNS was found to correspond to the f mode in the GCN, indicating the alternation of the mode trapping region between the core and the envelope. At later times, the three classification methods presented a similar description of the mode spectrum. Universal relations for the PNS modes were tested according to their classification, and the CBMP showed a remarkably simple behavior for the f and p modes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Physics, Nuclear
Mohamad Chamseddine, Jerome Margueron, Guy Chanfray, Hubert Hansen, Rahul Somasundaram
Summary: We investigate a relativistic Hartree-Fock Lagrangian with a chiral potential and nucleon polarization to better describe dense nuclear matter. We consider the exchange Fock term, nucleon's compositeness and finite size effects, and short-range correlations. The model parameters are adjusted to reproduce low-energy QCD properties and empirical properties at saturation. By employing Bayesian statistics, we analyze the uncertainties and show that the fit to the symmetry energy provides a very good equation of state compatible with nuclear physics knowledge.
EUROPEAN PHYSICAL JOURNAL A
(2023)
Article
Multidisciplinary Sciences
G. Fiorella Burgio, Hans-Josef Schulze, Isaac Vidana, Jin-Biao Wei
Summary: The study shows that almost all models are consistent with laboratory constraints and observations regarding nuclear matter properties, and no correlation was found between tidal deformability and the value of nuclear symmetry energy. However, very weak correlations might exist with the derivative of nuclear symmetry energy and nuclear incompressibility.
Article
Physics, Multidisciplinary
I Bombaci, A. Drago, D. Logoteta, G. Pagliara, I Vidana
Summary: The possibility of the low mass companion of the black hole in the source of GW190814 being a strange quark star has been investigated. It is viable within the two-families scenario where neutron stars and strange quark stars coexist. Strange quark stars and neutron stars fulfill different astrophysical and nuclear physics constraints.
PHYSICAL REVIEW LETTERS
(2021)
Review
Physics, Nuclear
G. F. Burgio, H. -J. Schulze, I. Vidana, J. -B. Wei
Summary: The paper reviews the current status and recent progress of microscopic many-body approaches and phenomenological models used in constructing the equation of state of neutron stars. Theoretical predictions of different equation-of-state models are compared with data from terrestrial laboratory experiments and recent astrophysical observations. The importance of nuclear strong interaction and equation of state for the cooling properties of neutron stars is also analyzed.
PROGRESS IN PARTICLE AND NUCLEAR PHYSICS
(2021)
Article
Astronomy & Astrophysics
Peter Shternin, Isaac Vidana
Summary: The study reveals that in dense matter, neutrons have a more significant contribution to transport coefficients compared to other baryons. Due to the onset of Sigma(-), which results in the deleptonization of the neutron star core, neutrons also dominate shear viscosity in the high density region.
Review
Astronomy & Astrophysics
Isaac Vidana
Summary: This work briefly reviews the role and properties of hyperons in finite and infinite nuclear systems, including hypernuclei and neutron stars. It discusses different production mechanisms of hypernuclei, aspects of their gamma-ray spectroscopy and weak decay modes, as well as the theoretical description of hyperons. The paper also reexamines the impact of hyperons on neutron and proto-neutron star properties, focusing on the hyperon puzzle and proposed solutions. Finally, it reviews the role of hyperons in the cooling properties of newly born neutron stars and the r-mode instability.
Article
Physics, Nuclear
Isaac Vidana
Summary: In this study, a feed-forward artificial neural network is employed to extrapolate the separation energy BA of the lightest hypernuclei "3AH, 4AH, and 4AHe" obtained from ab-initio hypernuclear No-Core Shell Model calculations to large model spaces. The overfitting problem is addressed by increasing the size of the input dataset and by introducing Gaussian noise during the training process of the neural network. The results show that the neural network with a single hidden layer of eight neurons is capable of accurately extrapolating the A separation energy to model spaces of size Nmax = 100.
Article
Physics, Multidisciplinary
J. L. Rodriguez-Sanchez, J. Cugnon, J. -C. David, J. Hirtz, A. Kelic-Heil, I. Vidana
Summary: Experimental studies combined with advanced calculations have successfully investigated the nuclear dissipation mechanism in normal nuclear matter. The dissipation coefficients have been well constrained in transport theories through the use of various fission observables. However, the investigation of the dissipation coefficient needs to be extended to the strangeness sector due to the presence of hypernuclei and possible hyperons in neutron stars.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Nuclear
Isaac Vidana, Domenico Logoteta, Ignazio Bombaci
Summary: We investigated the influence of chiral nuclear forces on the propagation of neutrinos in hot neutron matter. Our results showed that the dynamical structure factor and the neutrino mean free path depended on the cutoff only at leading order (LO) and next-to-leading order (NLO), but this dependence became strongly reduced at higher orders due to the contribution of three-nucleon forces. The uncertainty associated with our calculation of the neutrino mean free path was estimated and found to vary with density.
Article
Astronomy & Astrophysics
Rahul Kashyap, Abhishek Das, David Radice, Surendra Padamata, Aviral Prakash, Domenico Logoteta, Albino Perego, Daniel A. Godzieba, Sebastiano Bernuzzi, Ignazio Bombaci, Farrukh J. Fattoyev, Brendan T. Reed, Andre da Silva Schneider
Summary: In this study, we use a large number of numerical relativity simulations to determine the threshold mass for the formation of prompt black holes in equal-mass neutron star mergers. We also investigate the relationship between this threshold mass and various equations of state and neutron star properties. By combining this information with observational data, we are able to derive constraints on the radii and tidal deformability of neutron stars. Furthermore, we discuss how future observations can further refine our understanding of the properties of matter using the method proposed in this work.
Article
Physics, Nuclear
A. Lovato, I Bombaci, D. Logoteta, M. Piarulli, R. B. Wiringa
Summary: In this study, we obtained the equation of state of infinite neutron matter using highly realistic Hamiltonians and benchmarked three independent many-body methods. The results show that these methods provide similar equations of state when specific nucleon-nucleon potentials and three-body forces are used. However, at high densities, one method shows significantly lower energy compared to the others. The study also highlights the possibility of unphysical results when certain parameters are used in the calculations.
Article
Astronomy & Astrophysics
Aviral Prakash, David Radice, Domenico Logoteta, Albino Perego, Vsevolod Nedora, Ignazio Bombaci, Rahul Kashyap, Sebastiano Bernuzzi, Andrea Endrizzi
Summary: The study reveals that quark production in neutron star mergers occurs over a wide range of temperatures and densities due to matter crossing the phase boundary. The softening of the equation of state caused by the phase transition leads to more compact merger remnants and earlier collapse to black holes. The phase transition is reflected in the postmerger gravitational wave signals in terms of duration, amplitude, and peak frequency.
Article
Physics, Nuclear
Isaac Vidana
Summary: The study investigates the properties of a spin-down neutron impurity in a low-density free Fermi gas of spin-up neutrons, comparing the results with quantum Monte Carlo calculations and previous studies. It is found that the impurity's energy, effective mass, and quasiparticle residue exhibit slight variations within specific ranges, resembling those of an attractive Fermi polaron in the unitary limit. The research demonstrates compatibility with results derived from ultracold atoms, indicating similar properties under certain conditions.
Article
Physics, Nuclear
Phan Nhut Huan, Nguyen Le Anh, Bui Minh Loc, Isaac Vidana
Summary: The differential cross sections of charge-exchange reactions leading to the excitation of the isobaric analog state (IAS) of the target nucleus were calculated using the distorted wave Born approximation. The study found that the density and isospin dependences of the G matrices play a significant role in describing the experimental data accurately.
