Science topic

# Astrophysics - Science topic

Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior.
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Publications related to Astrophysics (10,000)
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Our existence in the Universe resulted from a rare combination of circumstances. The same must hold for any highly developed extraterrestrial civilisation, and if they have ever existed in the Milky Way, they would likely be scattered over large distances in space and time. However, all technologically advanced species must be aware of the unique p...
Article
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A scheme is put forward to generate fully coherent x-ray lasers based on population inversion in highly charged ions, created by fast inner-shell photoionization using broadband x-ray free-electron-laser (XFEL) pulses in a laser-produced plasma. Numerical simulations based on the Maxwell–Bloch theory show that one can obtain high-intensity, femtose...
Article
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For several years, reports have been published about fluctuations in measured radioactive decay time-series and in some instances linked to astrophysical as well as classical environmental influences. Anomalous behaviors of radioactive decay measurement and measurement of capacitance inside and outside a modified Faraday cage were documented by our...
Article
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Asteroids, comets and moons are leftovers of planet formation. Studying them and their samples, including meteorites, can help us to learn how the Earth was made and acquired the ingredients for life, to obtain practical information for deflecting near-Earth objects (NEOs), and to access resources that would enable space habitats and voyages. Answe...
Article
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The detection of gravitational waves emitted during a neutron star–black hole merger and the associated electromagnetic counterpart will provide a wealth of information about stellar evolution nuclear matter, and general relativity. While the theoretical framework about neutron star–black hole binaries formed in isolation is well established, the p...
Article
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Since its arrival at Jupiter in 2016, NASA’s Juno spacecraft has been performing high-precision measurement of the gravity and magnetic fields. When combined with numerical simulations, they provide a unique window to the dynamics in the planet’s deep atmosphere.
Article
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In this work, it is shown how a spacecraft equipped with a thrust and subjected to a drag force can be bounded at specific altitudes as function of the parameters of the thrust. It is used nonlinear dynamics tools to find attractors, which bound the motion of the spacecraft. For a specific set of parameters of the thrust, the spacecraft is bounded...
Article
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Superdense plasmas widely exist in planetary interiors and astrophysical objects such as brown-dwarf cores and white dwarfs. How atoms behave under such extreme-density conditions is not yet well understood, even in single-species plasmas. Here, we apply thermal density functional theory to investigate the radiation spectra of superdense iron–zinc...
Article
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
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The work shows few of many great Astrophysical secrets hidden in the God’s swear by locations of the stars, God says: (Furthermore I swear by The positions of the Stars, And that is indeed A mighty adjuration If ye but knew, That is indeed A Qur-an most honourable ) (S 56 A 75-77). This is manifested through mentioning some of the physical methods...
Conference Paper
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This paper is an inquiry about how the field of translation studies and translation-related issues could provide good practices for enabling successful transdisciplinary collaborations. The focus is on transdisciplinary practice and research, which bridge experts in very different disciplines that do not share success criteria, exact methodologies...
Preprint
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Parameter estimation with non-Gaussian stochastic fields is a common challenge in astrophysics and cosmology. In this paper, we advocate performing this task using the scattering transform, a statistical tool sharing ideas with convolutional neural networks (CNNs) but requiring no training nor tuning. It generates a compact set of coefficients, whi...
Preprint
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We derive universal properties of the near-horizon geometry of spherically symmetric black holes. These properties follow solely from the existence of an apparent horizon and its regularity. Only two types of solutions are possible, and both appear at different stages of the black hole formation. If semiclassical gravity is valid, then accretion af...
Preprint
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Using Magnetospheric Multiscale (MMS) observations at the Earth's quasi-parallel bow shock we demonstrate that electrons are heated by two different mechanisms: a quasi-adiabatic heating process during magnetic field compression, characterized by the isotropic temperature relation $T/B=(T_0/B_0)(B_0/B)^{\alpha}$ with $\alpha=2/3$ when the electron...
Article
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In this paper we have investigated the dynamics of neutral, electrically charged and magnetized particles around renormalized group improved (RGI) Schwarzschild black hole in the presence of external asymptotically uniform magnetic field. We have analyzed the spacetime structure around RGI black hole by investigating Ricci, the square of Ricci tens...
Preprint
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Mirrors are a subset of optical components essential for the success of current and future space missions. Most of the telescopes for space programs ranging from Earth Observation to Astrophysics and covering the whole electromagnetic spectrum from X-rays to Far-Infrared are based on reflective optics. Mirrors operate in diverse and harsh environme...
Preprint
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We show that the odds of the mass-gap (secondary) object in GW190814 being a neutron star (NS) improve if one allows for a stiff high-density equation of state (EoS) or a large spin, when employing a nuclear parameterization of the EoS. Since its mass is $\in (2.50,2.67) M_{\odot}$, establishing its true nature will make it either the heaviest neut...
Preprint
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The 21-cm absorption feature reported by the EDGES collaboration is several times stronger than that predicted by traditional astrophysical models. If genuine, a deeper absorption may lead to stronger fluctuations on the 21-cm signal on degree scales (up to 1~Kelvin in rms), allowing these fluctuations to be detectable in nearly 50~times shorter in...
Preprint
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Neutron star mergers (NSMs) are promising astrophysical sites for the rapid neutron-capture ("$r$-") process, but can their integrated yields explain the majority of heavy-element material in the Galaxy? One method to address this question has utilized a forward approach that propagates NSM rates and yields along with stellar formation rates, in th...
Preprint
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Multimessenger observations of the neutron star merger event GW170817 have re-energized the debate over the astrophysical origins of the most massive elements via the r-process nucleosynthesis. A key aspect of such studies is comparing astronomical observations to theoretical nucleosynthesis yields in a meaningful way. To perform realistic nucleosy...
Preprint
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The 3.6 meter Indo-Belgian Devasthal optical telescope (DOT) has been used for optical and near-infrared (NIR) observations of celestial objects. The telescope has detected stars of B = 24.5+-0.2; R = 24.6+-0.12 and g = 25.2+-0.2 mag in exposure times of 1200, 4320 and 3600 seconds respectively. In one hour of exposure time, a distant galaxy of 24....
Preprint
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We investigate the possibility that the low mass companion of the black hole in the source of GW190814 was a strange quark star. This possibility is viable within the so-called two-families scenario in which neutron stars and strange quark stars coexist. Strange quark stars can reach the mass range indicated by GW190814, $M\sim (2.5-2.67) M_\odot$...
Article
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
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Satellites orbiting disk galaxies can induce phase space features such as spirality, vertical heating and phase-mixing in their disks. Such features have also been observed in our own Galaxy, but the complexity of the Milky Way disk has only recently been fully mapped by Gaia Data Release 2 (DR2) data. This complex behaviour is mainly ascribed to r...
Preprint
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We introduce a new general-purpose time-dependent ionisation network (IN) and a radiation transport (RT) module in the magneto-hydrodynamic (MHD) code PLUTO. Our ionisation network is reliable for temperatures ranging from 5e3 to 3e8 K, and includes all ionisation states of H, He, C, N, O, Ne, Mg, Si, S and Fe making it suitable for studying a vari...
Preprint
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We investigate sustenance and dependence on magnetic Prandtl number (${\rm Pm}$) for magnetorotational instability (MRI)-driven turbulence in astrophysical Keplerian disks with zero net magnetic flux using standard shearing box simulations. We focus on the turbulence dynamics in Fourier space, capturing specific/noncanonical anisotropy of nonlinear...
Article
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Abstract The interaction (oblique collision) of two ion acoustic solitons (IASs) in a magnetized relativistic degenerate plasma with relativistic degenerate electrons and non-degenerate cold ions is studied. The extended Poincaré–Lighthill–Kuo (PLK) method is used to obtain two Korteweg deVries (KdV) wave equations that describe the interacting IAS...
Article
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The cosmic ray detector for the NICA collider; European Physical Journal; EPJ Conferences, vol.239, September 2020, art.no.07004; MultiPurpose Detector (MPD) is a main part of a New Ion Collider fAcility (NICA) located in Dubna, Russia. To increase MPD functionality, it was proposed to add an additional muon trigger system for off-beam calibrat...
Research
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Journal devoted to current developments in astronomy
Conference Paper
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The objective, statistical nature of SDSS astrophysical datasets, which were not driven by any theoretical agenda, reveal false and misleading prior measurements (e.g., redshift-distance) driven by confirmation bias in the context of such agendas. SDSS theta-z, redshift-magnitude (both spectroscopic and photometric pipelines), and galaxy population...
Preprint
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The laboratory simulations of jets from young stars that have been carried out for many years at plasma focus facilities allow the internal structure of the active regions emerging during the interaction of the jet with the surrounding plasma to be studied in detail. We have found a new wide class of solutions for the equations of ideal magnetohydr...
Preprint
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The baryogenesis presents the theoretical mechanism that describes the matter-antimatter asymmetry in the history of early universe. In this work, we investigate the gravitational baryogenesis phenomena in the frameworks of $f(T, T_G)$ (where $T$ and $T_G$ are the torsion scalar and teleparallel equivalent to the Gauss-Bonnet term respectively) and...
Article
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Magnetic fields in galaxies and galaxy clusters are amplified from a very weak seed value to the observed μG strengths by the turbulent dynamo. The seed magnetic field can be of primordial or astrophysical origin. The strength and structure of the seed field, on the galaxy or galaxy cluster scale, can be very different, depending on the seed-field...
Preprint
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Magnetic fields in galaxies and galaxy clusters are amplified from a very weak seed value to the observed $\mu{\rm G}$ strengths by the turbulent dynamo. The seed magnetic field can be of primordial or astrophysical origin. The strength and structure of the seed field, on the galaxy or galaxy cluster scale, can be very different, depending on the s...
Article
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Rovibrational energy levels of CP are investigated for its X 2 Σ+ and A 2 Π electronic states. Rovibronic fre- quencies observed experimentally for the A 2 Π-X 2 Σ+ transition are used to produce empirical energy levels with the MARVEL method (denoted as MARVEL energy levels). The MARVEL energy levels for the X 2 Σ+ and A 2 Π states are then employ...
Preprint
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It has been proposed that there could be a mirror copy of the standard model particles, restoring the parity symmetry in the weak interaction on the global level. Oscillations between a neutral standard model particle, such as the neutron, and its mirror counterpart could potentially answer various standing issues in physics today. Astrophysical st...
Preprint
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The mass gap in the secondary component of the GW190814 event left us, "whether it is a super-massive neutron star or light black-hole?". Recently, Fattoyev et al. have predicted the mass of the secondary component is 2.60 M_{\odot} based on the BigApple parameter set. We study the properties of finite nuclei, nuclear matter and neutron star by usi...
Article
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Whether ice in cold cosmic environments is physically separated from the silicate dust or mixed with individual silicate moieties is not known. However, different grain models give very different compositions and temperatures of grains. The aim of the present study is to compare the mid-infrared spectra of laboratory silicate grain/water ice mixtur...
Preprint
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Spectral retrieval techniques are currently our best tool to interpret the observed exoplanet atmospheric data. Said techniques retrieve the optimal atmospheric components and parameters by identifying the best fit to an observed transmission/emission spectrum. Over the past decade, our understanding of remote worlds in our galaxy has flourished th...
Preprint
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The Pencil Code is a highly modular physics-oriented simulation code that can be adapted to a wide range of applications. It is primarily designed to solve partial differential equations (PDEs) of compressible hydrodynamics and has lots of add-ons ranging from astrophysical magnetohydrodynamics (MHD) to meteorological cloud microphysics and enginee...
Preprint
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The coherent nature of gravitational wave emanating from a compact binary system makes it possible to detect some interference patterns in two (or more) signals registered simultaneously by the detector. Gravitational lensing effect can be used to bend trajectories of gravitational waves, which might reach the detector at the same time. Once this h...
Article
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Today's astrophysics has become so tangled up in questions of the solar cycle that there is actually no hope that it will get out of this mess on its own. Billion dollar programs such as SOHO, SDO have not made a single step forward in physics. What the probes have brought is again thousands of very nice pictures and movies, but cognitive: Zero, 'n...
Preprint
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We investigate interacting quark matter (IQM), including the perturbative QCD correction and color superconductivity, for both up-down quark matter ($ud$QM) and strange quark matter (SQM). We first derive an equation of state (EOS) unifying all cases by a simple reparametrization and rescaling, through which we manage to maximally reduce the number...
Article
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We study quantum corrections at the horizon scale of a black hole induced by a Generalized Uncertainty Principle (GUP) with a quadratic term in the momentum. The interplay between quantum mechanics and gravity manifests itself into a non-zero uncertainty in the location of the black hole radius, which turns out to be larger than the usual Schwarzsc...
Preprint
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Die heutige Astrophysik hat sich in Fragen des Sonnenzyklus derma?en verheddert, das es eigentlich keine Hoffnung mehr gibt dass sie von alleine aus diesem Schlamassel herauskommt. Milliardenschwere Programme wie SOHO, SDO haben bislang keinen, wen auch nur einen winzigen Schritt die Physik vorangebracht. Das was die Sonden gebracht haben es sind w...
Preprint
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The detection of binary neutron star mergers represents one of the most important and complex astrophysical discoveries of the recent years. One of the unclear aspects of the problem is the turbulent magnetic field amplification, initially triggered by the Kelvin-Helmholtz instability at much smaller scales than any reachable numerical resolution n...
Article
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In this article, we design a novel method for finding the exact solution of the geodesic equation in Schwarzschild spacetime, which represents the trajectories of the particles. This is a fundamental problem in astrophysics and astrodynamics if we want to incorporate relativistic effects in high precision calculations. Here, we show that exact anal...
Article
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Superradiance is the anomalous radiance describing coherent photon emission from a gas. It plays a crucial role in atomic physics, quantum mechanics and astrophysics. Because the intensity of superradiant light beams is proportional to the number of particles squared, superradiance is also at the core of today’s most powerful light sources. Superra...
Article
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LIGO and Virgo’s third observing run revealed the first neutron star–black hole (NSBH) merger candidates in gravitational waves. These events are predicted to synthesize r-process elements creating optical/near-infrared ‘kilonova’ emission. The joint gravitational wave and electromagnetic detection of an NSBH merger could be used to constrain the e...
Preprint
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Gamma-Ray Bursts (GRBs) are the most explosive phenomena in the Universe after the Big Bang. A large fraction of GRB lightcurves (LCs) shows X-ray plateaus. We perform the most comprehensive analysis of all GRBs (with known and unknown redshifts) with plateau emission observed by The Neil Gehrels Swift Observatory from its launch until August 2019....
Preprint
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The high school project on astrophysics research with cosmics (HiSPARC) employs a large number of small detection stations that sample the footprint of extensive cosmic ray air showers. The majority of these stations has two 0.5 \si{\meter\squared} scintillation detectors. A new method is presented which enables probing the cosmic ray flux with a s...
Preprint
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Based on Magnetospheric Multiscale (MMS) observations from the Earth's bow shock, we have identified two plasma heating processes that operate at quasi-perpendicular shocks. Ions are subject to stochastic heating in a process controlled by the heating function $\chi_j = m_j q_j^{-1} B^{-2}\mathrm{div}(\mathbf{E}_\perp)$ for particles with mass $m_j... Article Full-text available When galaxies merge, the supermassive black holes in their centers may form binaries and emit low-frequency gravitational radiation in the process. In this paper, we consider the galaxy 3C 66B, which was used as the target of the first multimessenger search for gravitational waves. Due to the observed periodicities present in the photometric and as... Article Full-text available Strong cosmic censorship conjecture is crucial for the deterministic nature of general relativity, since it asserts that given an initial data on a spacelike hypersurface the future can be uniquely predicted. However, for asymptotically de Sitter spacetimes, in the presence of Cauchy horizon, the metric and matter fields can be extended beyond the... Article Full-text available Multilayer (ML) thin film coatings have shown promise in achieving hard x-ray nanofocusing with high reflectivity and high resolution. The chemical, structural, and long-term stability of Ir/B4C MLs, which are of great interest to the synchrotron and astrophysics communities, are not yet fully understood. The evolution of the x-ray performance of I... Article Full-text available Following the results of our previous low-frequency searches for extraterrestrial intelligence (SETI) using the Murchison Widefield Array (MWA), directed towards the Galactic Centre and the Orion Molecular Cloud (Galactic Anticentre), we report a new large-scale survey towards the Vela region with the lowest upper limits thus far obtained with the... Preprint Full-text available To find more deliberate$f(R, T)$astrophysical solutions, we proceed by studying wormhole geometries under the assumption of spherical symmetry and the existence of a conformal Killing symmetry to attain the more acceptable astrophysical results. To do this, we consider a more plausible and simple model$f(R,T)=R+2\chi T$, where$R$is the Ricci s... Preprint Full-text available Cross-sections for${}^{nat}Pb(p,xn){}^{201-207}Bi$,${}^{204}Pb(p,1-4n){}^{201-204}Bi$and${}^{206}Pb(p,3n){}^{204}Bi$reactions have been determined in the astrophysical energy range$20-30 \, MeV$. The analysis were performed by$\gamma$-spectroscopy associated with half-lives measurements. The results were compared with previously experimental... Preprint Full-text available This work addresses the effect of travelling thermal waves applied at the fluid layer surface, on the formation of global flow structures in 2D and 3D convective systems. For a broad range of Rayleigh numbers ($10^3\leq Ra \leq 10^7$) and thermal wave frequencies ($10^{-4}\leq \Omega \leq 10^{0}$), we investigate flows with and without imposed mean... Article Full-text available The estimation of the main parameters of star clusters is a very important target in astrophysical studies. Many of the open clusters listed in known catalogs have insufficient astrometric parameters. Improving the observations and analysis methods proved that some of them are asterisms and not true clusters. The most important aspect of using the... Preprint Full-text available The gravitational-wave signal GW190521 is consistent with a binary black hole merger source at redshift 0.8 with unusually high component masses,$85^{+21}_{-14}\,M_{\odot}$and$66^{+17}_{-18}\,M_{\odot}\$, compared to previously reported events, and shows mild evidence for spin-induced orbital precession. The primary falls in the mass gap predicte...
Article
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We study the composition of nuclear matter at sub-saturation densities, non-zero temperatures, and isospin asymmetry, under the conditions characteristic of binary neutron star mergers, stellar collapse, and low-energy heavy-ion collisions. The composition includes light clusters with mass number A ≤ 4, a heavy nucleus (56 Fe), the Δ-resonances, th...
Article
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
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Numerical Relativity is a multidisciplinary field including relativity, magneto-hydrodynamics, astrophysics and computational methods, among others, with the aim of solving numerically highly-dynamical, strong-gravity scenarios where no other approximations are available. Here we describe some of the foundations of the field, starting from the cova...