Article
Astronomy & Astrophysics
S. Isayama, K. Takahashi, S. Matsukiyo, T. Sano
Summary: Counterpropagating Alfven waves are commonly observed in various astrophysical environments and can efficiently accelerate particles. Phase transitions of particle behavior occur when wave amplitudes exceed critical values, resulting in irreversible relativistic energy gain for particles. The accelerated particles have spatial coherence. The findings may have implications for astrophysical phenomena and future laboratory experiments using high-power lasers.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Caterina Chiari, Pierfrancesco Di Cintio
Summary: This study extends the classical formulation of dynamical friction on a test star to the case of relativistic velocities and velocity distributions, considering post-Newtonian corrections to the gravitational force. The results show that a test particle experiences slightly stronger drag when moving through a population of field stars with relativistic velocity distribution. This study also reveals that a purely classical treatment overestimates the effect of dynamical friction at low test particle velocities when post-Newtonian corrections should be included.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
W. Z. Shangguan, Z. Q. Huang, S. N. Wei, W. Z. Jiang
Summary: The study shows that hyperons have a significant impact on the tidal deformability of neutron stars, and lower onset density of hyperons can considerably modify the deformability and affect the inference on the nuclear EOS.
Article
Astronomy & Astrophysics
Ioulia Florou, Apostolos Mastichiadis, Maria Petropoulou
Summary: Relativistic hadronic plasmas can become supercritical, releasing energy through photon outbursts. This study investigates hadronic supercriticalities in adiabatically expanding sources, examining the trigger conditions and the role of expansion velocity. The results suggest a connection between these supercriticalities and gamma-ray burst prompt emission, providing insights into the formation of light curves and photon spectra.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Pavel Abolmasov, Omer Bromberg
Summary: The interaction between relativistic jets and the surrounding medium determines their dynamics and observational features. The contact discontinuity at the jet boundary, affected by jet collimation, may undergo Rayleigh-Taylor instability (RTI) and Richtmyer-Meshkov instability (RMI). This study examines the evolution of these instabilities in non-magnetized relativistic jets through special relativistic 3D hydrodynamic simulations. The results show that the growth of initial perturbations is consistent with relativistic RTI in the collimation region and RMI becomes important downstream from the collimation shock. The instabilities reach nonlinear scales and induce strong turbulence, mixing the jet with the surrounding matter.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Seong-Yeop Jeong, Clare Watt
Summary: The wave instability plays a vital role in redistributing energy and momentum in astrophysical plasmas. Understanding the wave energy density and growth rate is crucial for analyzing different wave instabilities in plasma regimes. In this study, we derived analytic expressions for the energy density and growth rate of resonant waves with arbitrary propagation angles in relativistic plasmas. Our results contribute to a better understanding of wave instability and have the potential to be combined with quasi-linear theory for studying the time evolution of particle momentum distribution and resonant wave properties.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Physics, Particles & Fields
Kaushik Bhattacharya, Anirban Chatterjee, Saddam Hussain
Summary: In this paper, we investigate a non-minimal, space-time derivative dependent coupling between the k-essence field and a relativistic fluid using a variational approach. By introducing a coupling term at the Lagrangian level, we obtain the k-essence field equation and the Friedmann equations for a spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) metric. Through dynamical analysis, we analyze the dynamics of this coupled scenario in the context of two interaction models, which can produce stable accelerating solutions and explain different phases of the evolutionary universe.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Nuclear
R. Francener, V. P. Goncalves, B. D. Moreira
Summary: This paper investigates the photoproduction of QED bound states in proton-proton, proton-nucleus, and nucleus-nucleus collisions at different energies, considering accurate treatment of absorptive corrections and nuclear form factors. The total cross sections for the production of singlet and triplet states, with different leptons, are estimated. The impact of Coulomb corrections on parapositronium production in heavy ion collisions is also evaluated. A large number of events associated with the production of electron-positron and muon-antimuon states in hadronic collisions are predicted.
EUROPEAN PHYSICAL JOURNAL A
(2022)
Article
Astronomy & Astrophysics
G. Bodo, G. Mamatsashvili, P. Rossi, A. Mignone
Summary: We analyze the evolution of current-driven kink instabilities in a highly magnetized relativistic plasma column and focus on its dissipation properties. The formation of thin current sheets where magnetic energy is dissipated occurs during the instability evolution. The dissipation occurs in two stages, with a peak stage characterized by the formation of a helicoidal current sheet and a weaker stage with turbulence development. The results have implications for high energy astrophysical sources.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Jin Matsumoto, Serguei S. Komissarov, Konstantinos N. Gourgouliatos
Summary: This study investigates the role of regular magnetic fields in the development of instability during the recollimation of relativistic jets. It demonstrates that a weak azimuthal magnetic field can suppress the instability in such jets. The results support the idea that the recollimation instability is related to the centrifugal instability.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Physics, Multidisciplinary
Lorenzo Sironi, Illya Plotnikov, Joonas Nattila, Andrei M. Beloborodov
Summary: The article presents first-principles 3D simulations providing essential information for models of fast radio bursts (FRBs) based on relativistic magnetized shocks, including parameters such as emission efficiency, spectrum, and polarization.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
Javier A. Garcia, Thomas Dauser, Renee Ludlam, Michael Parker, Andrew Fabian, Fiona A. Harrison, Joern Wilms
Summary: This article presents new reflection models specifically designed for modeling the X-ray radiation reprocessed in accretion disks around neutron stars. These models, which differ significantly from previous models, are tested using observations of the neutron star 4U 1705-44. Simulations of upcoming missions also demonstrate the diagnostic potential of these models for high-resolution X-ray reflection spectroscopy.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Lizhong Zhang, Omer Blaes, Yan-Fei Jiang
Summary: The study reveals that when high luminosity matter accretes onto a strongly magnetized neutron star, it forms a radiation pressure-dominated, magnetically confined accretion column. These columns are dynamically maintained through high-frequency oscillations of the accretion shock, which redistribute energy released at the shock through bulk vertical motions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Anthony Chow, Michael E. Rowan, Lorenzo Sironi, Jordy Davelaar, Gianluigi Bodo, Ramesh Narayan
Summary: We study the linear stability of a planar interface separating two fluids in relative motion, focusing on the symmetric configuration. We find that the lower bound of unstable shear velocities is determined by the velocity projection and the Alfven speed projection. In the frame where the two fluids move in opposite directions with equal speed, the upper bound of unstable velocities corresponds to an effective relativistic Mach number.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Dina Traykova, Katy Clough, Thomas Helfer, Emanuele Berti, Pedro G. Ferreira, Lam Hui
Summary: The presence of light bosonic scalars around black holes may result in distinctive dephasing of gravitational wave signals. Numerical studies show that the dynamical friction force on a black hole moving in a scalar field follows a relativistic scaling similar to that of supersonic collisional fluids and oscillates in time. The rapid force oscillations of real scalars could potentially leave an imprint on the trajectory.
Article
Astronomy & Astrophysics
Utsav Murarka, Kinjal Banerjee, Tuhin Malik, Constanca Providencia
Summary: This paper applies machine learning algorithms to predict the binding energy of atomic nuclei and constructs the outer crust equation of state of a neutron star. The study demonstrates that the model is comparable to existing models in terms of accuracy and provides guidance for the physics community in choosing suitable machine learning algorithms for their datasets.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Nuclear
Yasuhiko Tsue, Constanca Providencia, Joao da Providencia, Masatoshi Yamamura
Summary: This paper focuses on the su(2)-Lipkin model and discovers an unexpected discrepancy between the exact treatment and the conventional RPA method when calculating the excitation energy to the first excited state. To address this issue, the conventional RPA method is renewed and the su(2)-Lipkin model is modified to be applicable to nonclosed shell systems.
INTERNATIONAL JOURNAL OF MODERN PHYSICS E
(2022)
Article
Astronomy & Astrophysics
Helena Pais, Oleksii Ivanytskyi, Constanca Providencia
Summary: This study calculates the nuclear matter properties using a relativistic approach suitable for multi-component systems. The effects of density dependence of symmetry energy and Landau quantization in the presence of a strong external magnetic field are discussed. The results show a large dispersion in the calculated properties at high densities, as well as sensitivity of proton Landau mass and parameters to symmetry energy. The impact of magnetic field on nuclear properties is minimal except in a narrow range of densities near the crust-core transition.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Edoardo Giangrandi, Violetta Sagun, Oleksii Ivanytskyi, Constanca Providencia, Tim Dietrich
Summary: We propose a model of asymmetric bosonic dark matter with self-repulsion. By studying different distribution regimes, we find that condensed dark matter leads to smaller radius and tidal deformability compared to pure baryonic stars, while the presence of a dark matter halo increases the tidal deformability and total gravitational mass. We impose constraints on the model parameters based on the self-interaction cross section of dark matter and discuss smoking gun evidence of dark matter presence.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Tuhin Malik, Marcio Ferreira, Milena Bastos Albino, Constanca Providencia
Summary: This study analyzes the high-density behavior of nuclear matter using a relativistic mean field description with nonlinear meson interactions. A Bayesian inference technique is used to evaluate the model parameters and their output. The study identifies three distinct classes of equations of state based on the strength of the nonlinear vector field contribution, each correlated with different star properties distributions.
Article
Astronomy & Astrophysics
Marcio Ferreira, Valeria Carvalho, Constanca Providência
Summary: This study successfully extracts the nuclear matter properties from cold beta-equilibrium neutron star matter using deep neural networks. The DNN model achieved high accuracy in the test set and was able to accurately predict the nuclear matter parameters in a real-case scenario involving 33 nuclear models.
Article
Astronomy & Astrophysics
Tuhin Malik, Constanca Providencia
Summary: The possible signatures of hyperons inside neutron stars are discussed using a Bayesian inference framework. Based on nuclear matter and hypernuclei properties, as well as observational information, the general properties of neutron stars are examined. It is found that neutron stars described by equations of state that include hyperons have larger radius and tidal deformability, but smaller speed of sound compared to stars described by nucleonic equations of state. Specific constraints on the possible hyperon content of neutron stars are given based on measurements of mass and radius. The presence of hyperons inside neutron stars is compatible with current observations of pulsars and gravitational wave detection.
Article
Physics, Nuclear
Kauan D. Marquez, Debora P. Menezes, Helena Pais, Constanca Providencia
Summary: By using a relativistic mean-field description with density dependent couplings, the properties of neutron star matter with different compositions are analyzed. The presence of hyperons decreases the fraction of A baryons in the center of the star, while without hyperons, stars with a dominant A baryon composition are possible.
Review
Physics, Nuclear
S. Typel, M. Oertel, T. Klahn, D. Chatterjee, V Dexheimer, C. Ishizuka, M. Mancini, J. Novak, H. Pais, C. Providencia, Ad R. Raduta, M. Servillat, L. Tolos
Summary: CompOSE is an online repository of equations of state (EoS) for use in nuclear physics and astrophysics. It offers a collection of data tables for different EoS types and related physical quantities, software for data extraction and interpolation, and webtools for generating customized EoS tables. This manual is an updated version of the CompOSE service, providing a detailed description and instructions for users.
EUROPEAN PHYSICAL JOURNAL A
(2022)
Article
Astronomy & Astrophysics
Joao Aveiro, Felipe F. Freitas, Marcio Ferreira, Antonio Onofre, Constanca Providencia, Goncalo Goncalves, Jose A. Font
Summary: In this study, the YOLOv5 model is used for detecting binary neutron star coalescence events from gravitational-wave data, achieving high average precision values. The model shows potential for application in first-stage detection alarm pipelines.
Article
Physics, Nuclear
Tuhin Malik, B. K. Agrawal, Constanca Providencia
Summary: An important goal in astrophysics is to understand the equation of state and composition of neutron stars. This study uses the nucleonic direct Urca process as a probe to investigate the high density behavior of nuclear symmetry energy. The results show a strong correlation between the nuclear symmetry energy and neutron star mass, providing valuable constraints on its behavior at high density.
Article
Physics, Nuclear
Lami Suleiman, Morgane Fortin, Julian Leszek Zdunik, Constanca Providencia
Summary: The study revises fits of equations of state using unified tables for neutron star matter, aiming to model macroscopic parameters accurately. By fitting parameters to 52 unified equations of state, properties like mass, radius, tidal deformability, and moment of inertia of neutron stars are compared to ensure the accuracy of the fits. The fit error on macroscopic parameters is found to be small and within the measurement accuracy of current and next-generation telescopes.
Article
Astronomy & Astrophysics
Veronica Dexheimer, Marco Mancini, Micaela Oertel, Constanca Providencia, Laura Tolos, Stefan Typel
Summary: This article presents a combination of two quick guides that summarize relevant information about the CompOSE nuclear equation of state repository. The first guide is aimed at nuclear physicists and provides instructions on how to provide standard equation of state tables, while the second guide is meant for users and describes the basic procedures to obtain customized tables with equation of state data. Several examples are included to help both providers and users of the CompOSE database.
Article
Physics, Nuclear
Tiago Custodio, Helena Pais, Constanca Providencia
Summary: The production of light nuclei, hypernuclei, and heavy baryons in low-density stellar environments is studied using relativistic mean-field models. The presence of both hyperons and A baryons leads to a shift in the dissolution of clusters to higher densities and an increase in their abundance. This effect is more significant at lower charge fractions and higher temperatures.
Article
Astronomy & Astrophysics
Xiaopeng Wang, Jing Li, Jianjun Fang, Helena Pais, Constanca Providencia
Summary: In this study, the properties of nuclear matter in the innermost crust of neutron stars under a strong magnetic field are considered. The density dependence, nonhomogeneous matter, and crust structure are discussed. The results show that a strong magnetic field extends the crust, causing disconnected nonhomogeneous regions and increasing the proton fraction.
