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the frequency dependence of the longitudinal group speeds of trapped sausage waves plays an important role in determining impulsively generated wave trains, which have often been invoked to account for quasi-periodic signals in coronal loops. we examine how the group speeds ({v}{gr}) depend on angular frequency (ω) for... | impulsively generated sausage waves in coronal tubes with transversally continuous structuring |
we study the buoyant rise of magnetic flux tubes embedded in an adiabatic stratification using two-and three-dimensional, magnetohydrodynamic simulations. we analyze the dependence of the tube evolution on the field line twist and on the curvature of the tube axis in different diffusion regimes. to be able to achieve a... | multi-parametric study of rising 3d buoyant flux tubes in an adiabatic stratification using amr |
recently, the black hole x-ray binary (bhxb) nova muscae 1991 has been reported to be experiencing an extremely rapid orbital decay. so far, three bhxbs have anomalously high orbital-period derivatives, which cannot be interpreted by the standard stellar evolution theory. in this work, we investigate whether the resona... | fast orbital shrinkage of black hole x-ray binaries driven by circumbinary disks |
we investigate the behavior of quantum speed limit (qsl) time for a typical non-markovian system, a central spin coupled to a spin star configuration. we connect the qsl time with an external control and show that the effectiveness of the external magnetic field, as well as the coupling strength, is related to the fund... | quantum speed limit in a qubit-spin-bath system |
a significant fraction of white dwarfs possess a magnetic field with strengths ranging from a few kg up to about 1000 mg. however, the incidence of magnetism varies when the white dwarf population is broken down into different spectral types providing clues on the formation of magnetic fields in white dwarfs. several s... | clues to the origin and properties of magnetic white dwarfs |
isolated magnetic white dwarfs have field strengths ranging from 103g to 109g, and constitute an interesting class of objects. the origin of the magnetic field is still the subject of a hot debate. whether these fields are fossil, hence the remnants of original weak magnetic fields amplified during the course of the ev... | magnetic white dwarfs: observations, theory and future prospects |
in 2003, the magnetar xte j1810-197 started an outburst that lasted until early 2007. in the following 11 yr, the source stayed in a quiescent/low-activity phase. xte j1810-197 is one of the closest magnetars, hence its x-ray properties can be studied in detail even in quiescence and an extended monitoring has been car... | the 11 yr of low activity of the magnetar xte j1810-197 |
we present analytic calculations of the electromagnetic torques acting on a magnetic neutron star rotating in vacuum, including near-zone torques associated with the inertia of dipole and quadrupole magnetic fields. we incorporate these torques into the rotational dynamics of a rigid-body neutron star, and show that th... | electromagnetic torques, precession and evolution of magnetic inclination of pulsars |
we investigate the density-shear instability in hall-magnetohydrodynamics (hall-mhd) via numerical simulation of the full non-linear problem in the context of magnetar activity. we confirm the development of the instability of a plane-parallel magnetic field with an appropriate intensity and electron density profile, i... | magnetar activity via the density-shear instability in hall-mhd |
we have analysed xmm-newton and chandra observations of the transient magnetar xte j1810-197 spanning more than 11 yr, from the initial phases of the 2003 outburst to the current quiescent level. we investigated the evolution of the pulsar spin period and we found evidence for two distinct regimes: during the outburst ... | the variable spin-down rate of the transient magnetar xte j1810-197 |
the configuration of the magnetic field in the interior of a neutron star is mostly unknown from observations. theoretical models of the interior magnetic field geometry tend to be oversimplified to avoid mathematical complexity and tend to be based on axisymmetric barotropic fluid systems. these static magnetic equili... | does elasticity stabilize a magnetic neutron star? |
the evolution of a large-scale poloidal magnetic field in an accretion disc is an important problem because it determines the launching of winds and the feasibility of the magnetorotational instability to generate turbulence or channel flows. recent studies, both semi-analytical calculations and numerical simulations, ... | local semi-analytic models of magnetic flux transport in protoplanetary discs |
the dependence dp/dt(p) is analyzed for three groups of pulsars with different period values: p > 2 s, 0.1 s < p < 2 s, and p < 0.1 s. under the assumption of a slow decay of the magnetic field of neutron stars during their evolution, as well as the slow change in the angle between its magnetic moment and t... | on braking mechanisms in radio pulsars |
the extreme properties of neutron stars provide unique opportunities to put constraints on new particles and interactions. in this paper, we point out a few interesting ideas that place constraints on light millicharged fermions, with masses below around an ev, from neutron star astrophysics. the model-independent boun... | novel astrophysical probes of light millicharged fermions through schwinger pair production |
we study the evolution of newborn neutron stars in high-mass x-ray binaries interacting with a wind-fed super-eddington disk. the inner disk is regularized to a radiation-dominated quasi-spherical configuration for which we calculate the inner radius of the disk, the total luminosity of the system and the torque acting... | ultra-luminous x-ray sources as super-critical propellers |
force on proton vortices in superfluid and superconducting matter of neutron stars is calculated at vanishing stellar temperature. both longitudinal (dissipative) and transverse (lorentz-type) components of the force are derived in a coherent way and compared in detail with the corresponding expressions available in th... | force on proton vortices in superfluid neutron stars |
we conducted near-infrared (jhk_s) imaging polarimetry toward the infrared dark cloud (irdc) m 17 swex, including almost all of the irdc filaments as well as its outskirts, with the polarimeter sirpol on the irsf 1.4 m telescope. we revealed the magnetic fields of m 17 swex with our polarization-detected sources that w... | near-infrared imaging polarimetry toward m 17 swex |
we report on pulse profile decomposition analysis of bright transient x-ray pulsar 1a 0535+262 using broadband insight-hxmt observations during a giant outburst of the source in 2020. we show that the observed pulse profile shape can be described in terms of a combination of two symmetric single-pole contributions for ... | beam pattern evolution of accreting x-ray pulsar 1a 0535+262 during its 2020 giant outburst |
an integral field unit (ifu) based on image slicers has been added to the gregor infrared spectrograph (gris). this upgrade to the instrument makes possible 2d spectropolarimetry in the near-infrared by simultaneously recording the full stokes profiles of spectral lines (in a given spectral interval) at all the points ... | first light of the integral field unit of gris on the gregor solar telescope |
the high-mass x-ray binary ls i + 61°303 is also cataloged as a gamma-ray binary as a result of frequent outbursts at tev photon energies. the system has released two soft-gamma flares in the past, suggesting a magnetar interpretation for the compact primary. this inference has recently gained significant traction foll... | does the gamma-ray binary ls i + 61°303 harbor a magnetar? |
in this paper, we report 23 magnetic field measurements of the b3iv star hd 23478: 12 obtained from high-resolution stokes v spectra using the espadons (canada-france-hawaii telescope) and narval (télescope bernard lyot) spectropolarimeters, and 11 from medium-resolution stokes v spectra obtained with the dimapol spect... | confirming hd 23478 as a new magnetic b star hosting an hα-bright centrifugal magnetosphere |
turbulence in space plasmas usually exhibits two regimes separated by a spectral break that divides the so called inertial and kinetic ranges. large scale magnetic fluctuations are dominated by non-linear mhd wave-wave interactions following a -5/3 or -2 slope power-law spectrum. after the break, at scales in which kin... | the effect of background turbulence on the relaxation of ion temperature anisotropy in space plasmas |
aims: massive b-type stars with strong magnetic fields and fast rotation are very rare and pose a mystery for theories of star formation and magnetic field evolution. only two such stars, called σ ori e analogues, were known until recently. a team involved in apogee, one of the sloan digital sky survey iii programs, an... | b fields in ob stars (bob): fors 2 spectropolarimetric follow-up of the two rare rigidly rotating magnetosphere stars hd 23478 and hd 345439 |
the sun and sun-like stars lose angular momentum to their magnetized stellar winds. this braking torque is coupled to the stellar magnetic field, such that changes in the strength and/or geometry of the field modifies the efficiency of this process. since the space age, we have been able to directly measure solar wind ... | solar angular momentum loss over the past several millennia |
recent exoplanet studies have revealed that the orbital planes of planets are not always aligned with one another or with the equatorial plane of the central star. the misalignment has been ascribed to gravitational scattering by giant planets and/or companion stars1-3 or to fly-bys in stellar cluster environments4. al... | a warped disk around an infant protostar |
by applying magnetohydrodynamic simulations, we investigate the launching of jets driven by a disk magnetic field generated by a mean-field disk dynamo. extending our earlier studies, we explore the bipolar evolution of the disk α 2ω-dynamo and the outflow. we confirm that a negative dynamo-α leads to a dipolar field g... | bipolar jets launched by a mean-field accretion disk dynamo |
fluctuations in the flow velocity and magnetic fields are ubiquitous in the solar system. these fluctuations are turbulent, in the sense that they are disordered and span a broad range of scales in both space and time. the study of solar wind turbulence is motivated by a number of factors all keys to the understanding ... | turbulence in the solar wind: spectra from voyager 2 data at 5 au |
we employ high-resolution spectroscopy and spectropolarimetry to derive the physical properties and magnetic characteristics of the multiple system hd 164492c, located in the young open cluster m20. the spectrum reveals evidence of three components: a broad-lined early b star (hd 164492c1), a narrow-lined early b star ... | hd 164492c: a rapidly rotating, hα-bright, magnetic early b star associated with a 12.5 d spectroscopic binary |
young neutron stars (nss) have magnetic fields in the range 1012-1015 g, believed to be generated by dynamo action at birth. we argue that such a dynamo is actually too inefficient to explain the strongest of these fields. dynamo action in the mature star is also unlikely. instead we propose a promising new precession-... | generating neutron-star magnetic fields: three dynamo phases |
ram-pressure stripping is a crucial evolutionary driver for cluster galaxies and jellyfish galaxies characterized by very extended tails of stripped gas, and they are the most striking examples of it in action. recently, those extended tails are found to show ongoing star formation, raising the question of how the stri... | role of magnetic fields in ram pressure stripped galaxies |
this paper reports on the x-ray emission evolution of the ultraluminous galactic x-ray pulsar swift j0243.6+6124 during the giant outburst from 2017 october to 2018 january as observed by the maxi gsc all-sky survey. the 2-30 kev light curve and the energy spectra confirm the source luminosity lx assuming an isotropic ... | x-ray emission evolution of the galactic ultraluminous x-ray pulsar swift j0243.6+6124 during the 2017-2018 outburst observed by the maxi gsc |
context. massive binary stars play a crucial role in many astrophysical fields. investigating the statistical properties of massive binary stars is essential to trace the formation of massive stars and constrain the evolution of stellar populations. however, no consensus has been achieved on the statistical properties ... | the statistical properties of early-type stars from lamost dr8 |
we study the instability of magnetic fields in a neutron star core driven by the parity violating part of the electron-nucleon interaction in the standard model. assuming a seed field of the order 1012 g, that is a common value for pulsars, one obtains its amplification due to such a novel mechanism by about five order... | generation of the magnetic helicity in a neutron star driven by the electroweak electron-nucleon interaction |
almost 50 years after radio pulsars were discovered in 1967, our understanding of these objects remains incomplete. on the one hand, within a few years it became clear that neutron star rotation gives rise to the extremely stable sequence of radio pulses, that the kinetic energy of rotation provides the reservoir of en... | radio pulsars |
context. observations from the solar dynamics observatory (sdo) have the potential for allowing the helioseismic study of the formation of hundreds of active regions, which would enable us to perform statistical analyses.aims: our goal is to collate a uniform data set of emerging active regions observed by the sdo/hmi ... | sdo/hmi survey of emerging active regions for helioseismology |
in the present study, the magnetic field scaling on density, | b| \propto {ρ }κ , was revealed in a single starless core for the first time. the κ index of 0.78 ± 0.10 was obtained toward the starless dense core fest 1-457 based on the analysis of the radial distribution of the polarization angle dispersion of backgrou... | distortion of magnetic fields in a starless core. iv. magnetic field scaling on density and mass-to-flux ratio distribution in fest 1-457 |
context. massive stars with solar metallicity lose important amounts of rotational angular momentum through their winds. when a magnetic field is present at the surface of a star, efficient angular momentum losses can still be achieved even when the mass-loss rate is very modest, at lower metallicities, or for lower-in... | close binary evolution. ii. impact of tides, wind magnetic braking, and internal angular momentum transport |
magnetic fields in wolf-rayet (wr) stars are not well explored, although there is indirect evidence, e.g. from spectral variability and x-ray emission, that magnetic fields should be present in these stars. being in an advanced stage of their evolution, wr stars have lost their hydrogen envelope, but their dense winds ... | the search for magnetic fields in two wolf-rayet stars and the discovery of a variable magnetic field in wr 55 |
the spin axis of a rotationally deformed planet is forced to precess about its orbital angular momentum vector, due to the tidal gravity of its host star, if these directions are misaligned. this induces internal fluid motions inside the planet that are subject to a hydrodynamic instability. we study the turbulent damp... | on turbulence driven by axial precession and tidal evolution of the spin-orbit angle of close-in giant planets |
we investigate the evolution of fast magnetoacoustic pulses in randomly structured plasmas, in the context of large-scale propagating waves in the solar atmosphere. we perform one-dimensional numerical simulations of fast wave pulses propagating perpendicular to a constant magnetic field in a low-β plasma with a random... | evolution of fast magnetoacoustic pulses in randomly structured coronal plasmas |
measurements of solar wind turbulence reveal the ubiquity of discontinuities. in this study we investigate how the discontinuities, especially rotational discontinuities (rds), are formed in mhd turbulence. in a simulation of the decaying compressive three-dimensional (3d) mhd turbulence with an imposed uniform backgro... | the formation of rotational discontinuities in compressive three-dimensional mhd turbulence |
the modification of the rotating vector model in the case of magnetars are calculated. magnetars may have twisted magnetic field compared with normal pulsars. the polarization position angle of magnetars will change in the case of a twisted magnetic field. for a twisted dipole field, we found that the position angle wi... | rotating vector model for magnetars |
the kelvin-helmholtz (kh) instability of a shear layer with an initially-uniform magnetic field in the direction of flow is studied in the framework of 2d incompressible magnetohydrodynamics with finite resistivity and viscosity using direct numerical simulations. the shear layer evolves freely, with no external forcin... | the impact of magnetic fields on momentum transport and saturation of shear-flow instability by stable modes |
we present results from a circular polarimetric survey of candidate detached magnetic white dwarf - m dwarf binaries obtained using the nordic optical telescope, la palma. we obtained phase resolved spectropolarimetry and imaging polarimetry of seven systems, five of which show clearly variable circular polarisation. t... | circular polarimetry of suspect wind-accreting magnetic pre-polars |
in the work we present the results of two deep broadband observations of the poorly studied x-ray pulsar igr j19294+1816 obtained with the nustar observatory. the source was observed during type i outburst and in the quiescent state. in the bright state a cyclotron absorption line in the energy spectrum was discovered ... | study of the x-ray pulsar igr j19294+1816 with nustar: detection of cyclotron line and transition to accretion from the cold disk |
we study the recently observed jellyfish galaxies (jfgs), which are found to have their gas content ram pressure stripped away in galaxy clusters. these galaxies are observed to have an enhanced star formation rate of about 0.2 dex compared with a control sample of the same stellar mass in their discs. we model the inc... | explaining the enhanced star formation rate of jellyfish galaxies in galaxy clusters |
x-ray observations play a crucial role in understanding the emission mechanism and relevant physical phenomena of magnetars. we report on x-ray observations made in 2016 of a young magnetar, sgr 1900+14, which is famous for a giant flare in 1998 august. simultaneous observations were conducted with xmm-newton and nusta... | temporal and spectral x-ray properties of magnetar sgr 1900+14 derived from observations with nustar and xmm-newton |
ambipolar diffusion likely plays a pivotal role in the formation and evolution of dense cores in weakly ionized molecular clouds. linear analyses show that the evolutionary times and fragmentation scales are significantly greater than the hydrodynamic (jeans) values even for clouds with mildly supercritical mass-to-flu... | variation of the core lifetime and fragmentation scale in molecular clouds as an indication of ambipolar diffusion |
implosive formation of current sheets is a fundamental plasma process. previous studies focused on the early time evolution, while here our primary aim is to explore the longer-term evolution, which may be critical for determining the efficiency of energy release. to address this problem, we investigate two closely rel... | resistively-limited current sheet implosions in planar anti-parallel (1d) and null-point containing (2d) magnetic field geometries |
accreting white dwarfs in binary systems known as cataclysmic variables (cvs) have in recent years been shown to produce radio flares during outbursts, qualitatively similar to those observed from neutron star and black hole x-ray binaries, but their ubiquity and energetic significance for the accretion flow has remain... | late-outburst radio flaring in ss cyg and evidence for a powerful kinetic output channel in cataclysmic variables |
we present the discovery of a magnetic field on the white dwarf component in the detached post-common envelope binary (pceb) cc cet. magnetic white dwarfs in detached pcebs are extremely rare, in contrast to the high incidence of magnetism in single white dwarfs and cataclysmic variables. we find zeeman-split absorptio... | discovery of a young pre-intermediate polar |
the last few decades have seen significant progress in our understanding of the occurrence of magnetic fields in stars with radiative envelopes, in particular in massive stars and in intermediate mass stars at early evolutionary stages. this book provides a comprehensive review of the most recent achievements in the me... | magnetic fields in o, b, and a stars |
any observable repercussion of electromagnetic properties of neutrinos will provide a perspicuous signature of new physics. this includes the phenomenon of neutrino spin flip in the propinquity of an external magnetic field. in this work, we study the inklings of spin flip in a neutron star with a radially varying magn... | can neutron star discriminate between dirac and majorana neutrinos? |
we present the analysis of archival xmm-newton european photon imaging camera (epic) x-ray observations of the symbiotic star r aquarii. we used the extended source analysis software package to disclose diffuse soft x-ray emission extending up to 2.'2 (≈0.27 pc) from this binary system. the depth of these xmm-newton ep... | an xmm-newton epic x-ray view of the symbiotic star r aquarii |
in order to predict the spins of stellar remnants we need to understand the evolution of the internal rotation of stars, and to identify at which stage the rotation of the contracting cores of evolved stars decouples from their expanding envelopes. the donor stars of mass transferring binaries lose almost their entire ... | the spins of stripped b stars support magnetic internal angular momentum transport |
euv imaging observations from several space missions (soho/eit, trace, and sdo/aia) have revealed a presence of propagating intensity disturbances in solar coronal loops. these disturbances are typically interpreted as slow magnetoacoustic waves. however, recent spectroscopic observations with hinode/eis of active regi... | excitation of flare-induced waves in coronal loops and the effects of radiative cooling |
a canonical description of a corotating solar wind high-speed stream in terms of velocity profile would indicate three main regions: a stream interface or corotating interaction region characterized by a rapid increase in flow speed and by compressive phenomena that are due to dynamical interaction between the fast win... | sudden depletion of alfvénic turbulence in the rarefaction region of corotating solar wind high-speed streams at 1 au: possible solar origin? |
fingering convection is a turbulent mixing process that can occur in stellar radiative regions whenever the mean molecular weight increases with radius. in some cases, it can have a significant observable impact on stellar structure and evolution. the efficiency of mixing by fingering convection as a standalone process... | the interaction between shear and fingering (thermohaline) convection |
we describe a method of implementing the axisymmetric evolution of general-relativistic hydrodynamics and magnetohydrodynamics through modification of a multipatch grid scheme. in order to ease the computational requirements required to evolve the post-merger phase of systems involving binary compact massive objects in... | axisymmetric hydrodynamics in numerical relativity using a multipatch method |
we investigate in this paper the structures of neutron stars under a strong magnetic field in the framework of f( t) gravity, where t denotes the scalar torsion. the tov equations in this theory of gravity have been considered and the numerical resolution of these equations has been performed within the perturbative ap... | strong magnetic field effects on neutron stars within f(t) theory of gravity |
we present high-speed optical photometric observations, spanning ∼2 yr, of the recently discovered white dwarf pulsar ar scorpii. the amplitudes of the orbital, spin, and beat modulations appear to be remarkably stable and repeatable over the time span of our observations. it has been suggested that the polarized and n... | a reevaluation of the proposed spin-down of the white dwarf pulsar in ar scorpii |
magnetars are neutron stars with extremely high surface magnetic fields. they show diverse x-ray pulse profiles in the quiescent state. we perform a systematic fourier analysis of their soft x-ray pulse profiles. we find that most magnetars have a single-peaked profile and hence have low amplitudes of the second fourie... | a systematic study of soft x-ray pulse profiles of magnetars in quiescence |
it is commonly believed that the magnetic field threading a neutron star provides the ultimate mechanism (on top of fluid viscosity) for enforcing long-term corotation between the slowly spun-down solid crust and the liquid core. we show that this argument fails for axisymmetric magnetic fields with closed field lines ... | persistent crust-core spin lag in neutron stars |
we investigate properties of a solar wind-like plasma, including a secondary alpha particle population exhibiting a parallel temperature anisotropy with respect to the background magnetic field, using linear and quasi-linear predictions and by means of one-dimensional hybrid simulations. we show that anisotropic alpha ... | fire hose instability driven by alpha particle temperature anisotropy |
we analyze the latest suzaku observation of the bright neutron star (ns) low-mass x-ray binary serpens x-1 taken in 2013 october and 2014 april. the observation was taken using the burst mode and only suffered mild pile-up effects. a broad iron line is clearly detected in the x-ray spectrum. we test different models an... | on the evolution of the inner disk radius with flux in the neutron star low-mass x-ray binary serpens x-1 |
the long-term rotational evolution of the old, isolated pulsar, psr b0950+08, is intriguing in that its spin-down rate displays sinusoidal-like oscillations due to alternating variations, both in magnitude and sign, of the second time derivative of the pulse frequency. we show that the large internal temperature to pin... | on the peculiar rotational evolution of psr b0950+08 |
assuming wind-fed accretion magnetars in long-period x-ray pulsars, we calculated the rotational evolution of neutron stars. our calculations considered the effects of magnetic field decay in magnetars. the results show that wind-fed accretion magnetars can evolve to long-period x-ray pulsars with a spin period much lo... | understanding the coexistence of spin-up and spin-down behaviours in long-period x-ray pulsars |
we present a study of timing properties of the accreting pulsar 2s 1417-624 observed during its 2018 outburst, based on swift/bat, fermi/gbm, insight-hxmt, and nicer observations. we report a dramatic change of the pulse profiles with luminosity. the morphology of the profile in the range 0.2-10.0 kev switches from dou... | timing analysis of 2s 1417-624 observed with nicer and insight-hxmt |
psr j1141-6545 is a precessing binary pulsar that has the rare potential to reveal the two-dimensional structure of a non-recycled pulsar emission cone. it has undergone ∼25° of relativistic spin precession in the ∼18 yr since its discovery. in this letter, we present a detailed bayesian analysis of the precessional ev... | relativistic spin precession in the binary psr j1141-6545 |
the tayler instability (ti) is a non-axisymmetric linear instability of an axisymmetric toroidal magnetic field in magnetohydrostatic equilibrium (mhse). in a differentially rotating radiative region of a star, the ti could drive the tayler-spruit dynamo, which generates magnetic fields that can significantly impact st... | the tayler instability in the anelastic approximation |
bright-rimmed clouds (brcs) are formed at the periphery of h ii regions as the radiation from the central star interacts with dense gas. the ionization and resulting compression of the clouds may lead to cloud disruption causing secondary star formation depending on the stellar and gas parameters. here we use r-band po... | magnetic field structure of ic 63 and ic 59 associated with h ii region sh 185 |
we have developed a new numerical code that is able to perform 2.5d simulations of a magnetohydrodynamic (mhd) wave propagation in the corona, and its interaction with a low-density region, such as a coronal hole (ch). we show that the impact of the wave on the ch leads to different effects, such as reflection and tran... | a numerical simulation of coronal waves interacting with coronal holes. i. basic features |
spin precession equations including the spin-orbit (so), spin-spin (ss), quadrupole-monopole (qm) and magnetic dipole-magnetic dipole (dd) leading-order interactions are derived for compact binary systems in order to investigate the dd contribution in the orbit-averaged spin precession equations for binary neutron star... | spin precession of binary neutron stars with magnetic dipole moments |
the origin and evolution of magnetic fields of neutron stars from birth have long been a source of debate. here, motivated by recent simulations of the hall cascade with magnetic helicity, we invoke a model where the large-scale magnetic field of neutron stars grows as a product of small-scale turbulence through an inv... | confronting the neutron star population with inverse cascades |
we use archival wise and spitzer photometry to derive optical line fluxes for a sample of distant quasars at z ~6. we find evidence for exceptionally high equivalent width [oiii] emission (rest-frame ew ~400 å) similar to that inferred for star-forming galaxies at similar redshifts. the median halpha and hbeta equivale... | insights into physical conditions and magnetic fields from high redshift quasars |
context. we explore the formation, energetics, and geometry of relativistic jets along with the variability of their central engine. we study both fast and slowly rotating black holes and address our simulations to active galaxy centers as well as gamma ray burst engines.aims: the structured jets are postulated to acco... | magnetically arrested accretion disks launching structured jets in application to grb and agn engines |
situation with highly magnetized neutron stars in binary systems is not yet certain. on the one hand, all best studied magnetars seem to be isolated objects. on the other, there are many claims based on model-dependent analysis of spin properties or/and luminosity of neutron stars in x-ray binaries in favour of large f... | high magnetic field neutron stars and magnetars in binary systems |
we use the point process mapping (ppmap) algorithm to reanalyse the herschel and scuba-2 observations of the l1688 and l1689 subregions of the ophiuchus molecular cloud. ppmap delivers maps with high resolution (here 14 arcsec, corresponding to ${\sim}0.01\, {\rm pc}$ at ${\sim}140\, {\rm pc}$), by using the observatio... | a ppmap analysis of the filamentary structures in ophiuchus l1688 and l1689 |
the circumnuclear disc (cnd) orbiting the galaxy's central black hole is a reservoir of material that can ultimately provide energy through accretion, or form stars in the presence of the black hole, as evidenced by the stellar cluster that is presently located at the cnd's centre. in this paper, we report the results ... | the inner cavity of the circumnuclear disc |
context. despite 50 yr of extensive binary research, we must conclude that the roche lobe overflow/mass transfer process that governs close binary evolution is still poorly understood.aims: it is the scope of the present paper to lift the edge of the veil by studying the spin-up and spin-down processes of the o-type co... | spin rates and spin evolution of o components in wr+o binaries |
in certain astrophysical systems, the commonly employed ideal magnetohydrodynamics (mhd) approximation breaks down. here, we introduce novel explicit and implicit numerical schemes of ohmic resistivity terms in the moving-mesh code arepo. we include these non-ideal terms for two mhd techniques: the powell 8-wave formal... | non-ideal magnetohydrodynamics on a moving mesh |
g. srinivasan et al. (1990) proposed a simple and elegant explanation for the reduction of the neutron star magnetic dipole moment during binary evolution leading to low mass x-ray binaries and eventually to millisecond pulsars: quantized vortex lines in the neutron star core superfluid will pin against the quantized f... | flux-vortex pinning and neutron star evolution |
the mirror mode evolving in collisionless magnetised high-temperature thermally anisotropic plasmas is shown to develop an interesting macro-state. starting as a classical zero-frequency ion fluid instability it saturates quasi-linearly at very low magnetic level, while forming elongated magnetic bubbles which trap the... | electron pairing in mirror modes: surpassing the quasi-linear limit |
a framework is introduced for coupling the evolution of galactic magnetic fields sustained by the mean-field dynamo with the formation and evolution of galaxies in cold dark matter cosmology. estimates of the steady-state strength of the large-scale and turbulent magnetic fields from mean-field and fluctuation dynamo m... | galactic magnetic fields and hierarchical galaxy formation |
we examine the magnetic field evolution occurring in a neutron star crust. beyond the elastic limit, the lattice ions are assumed to act as a plastic flow. the ohmic dissipation, hall drift, and bulk fluid velocity driven by the lorentz force are considered in our numerical simulation. a magnetically induced quadrupole... | evolution of magnetic deformation in neutron star crust |
short-orbit gas giant planet formation/evolution mechanisms are still not well understood. one promising pathway to discriminate between mechanisms is to constrain the occurrence rate of these peculiar exoplanets at the earliest stage of the system's life. however, a major limitation when studying newly born stars is s... | planets around young active solar-type stars: assessing detection capabilities from a non-stabilized spectrograph |
g183-35 is an unusual white dwarf that shows an h α line split into five components, instead of the usual three components seen in strongly magnetic white dwarfs. potential explanations for the unusual set of lines include a double degenerate system containing two magnetic white dwarfs and/or rotational modulation of a... | a magnetic white dwarf with five h α components |
observations of the faraday rotation measure, combined with the dispersion measure, can be used to infer the magnetoionic environment of a radio source. we investigate the magnetoionic environments of fast radio bursts (frbs) by deriving their estimated average magnetic field strengths along the line of sight <b∥>... | on the magnetoionic environments of fast radio bursts |
we report the orbital x-ray variability of the high-mass x-ray binary (hmxb) gx 301-2. gx 301-2 underwent a spin-up process in 2018-2020 with the period evolving from ~685-670 s. the energy-resolved pulse profiles of the pulsar at 1-60 kev varied from single-peaked and sinusoidal shapes to multipeaked ones across diffe... | timing and spectral variability of the high-mass x-ray pulsar gx 301-2 over orbital phases observed by insight-hxmt |
we investigate the relation between rotation periods p rot and photometric modulation amplitudes r per for ≈4000 sun-like main-sequence stars observed by kepler, using p rot and r per from mcquillan et al., effective temperature t eff from lamost dr6, and parallax data from gaia edr3. as has been suggested in previous ... | on the evolution of rotational modulation amplitude in solar-mass main-sequence stars |
we present a detailed study of the high-mass x-ray binary vela x-1, using observations performed by insight-hxmt in 2019 and 2020, concentrating on timing analysis and spectral studies including pulse phase-resolved spectroscopy. the cyclotron line energy is found to be ~21-27 and 43-50 kev for the fundamental and firs... | variations of cyclotron resonant scattering features in vela x-1 revealed with insight-hxmt |
we present a study based on the high-resolution spectroscopy and k2 space photometry of five chemically peculiar stars in the region of the open cluster m44. the analysis of the high-precision photometric k2 data reveals that the light variations in hd 73045 and hd 76310 are rotational in nature and caused by spots or ... | study of chemically peculiar stars - i. high-resolution spectroscopy and k2 photometry of am stars in the region of m44 |
context.σ ori e, a massive helium b-type star, shows high surface rotation and a strong surface magnetic field, potentially challenging the process of wind magnetic braking.aims: the gaia satellite provides an accurate distance to σ ori e and confirms its membership to the σ ori cluster. we account for these two key pi... | news from gaia on σ ori e: a case study for the wind magnetic braking process |
plasma relaxation in the presence of an initially braided magnetic field can lead to self-organization into relaxed states that retain non-trivial magnetic structure. these relaxed states may be in conflict with the linear force-free fields predicted by the classical taylor theory, and remain to be fully understood. he... | evolution of field line helicity in magnetic relaxation |
the correlation between space environment conditions and the properties of escaping ions is a central topic of mars research. although empirical correlations have been visible in the data, a physics-based interpretation, rather than statistics-based pictures, has not been established yet. as a first effort, we investig... | solar wind interaction with mars: electric field morphology and source terms |
orca (oscillations research with cosmics in the abyss) is the low-energy branch of km3net, the underwater cherenkov neutrino detector in the mediterranean. its primary goal is to resolve the long-standing unsolved question of the neutrino mass ordering by measuring matter oscillation effects in atmospheric neutrinos. t... | km3net - orca: measuring the neutrino mass ordering in the mediterranean |
reno (reactor experiment for neutrino oscillation) has obtained the first measured value of effective neutrino mass difference from a spectral analysis of reactor neutrino disappearance. the measurement absolutely relies on the accurate energy calibration. several radioactive sources such as 137cs, 54mn, 68ge, 65zn, 60... | prompt energy calibration at reno |
the opera experiment reached its main goal by proving the appearance of ν_{τ} in the cngs ν_μ beam. five ν_{τ} candidates were detected with a s/b ratio of ∼ 10, allowing to reject the null hypothesis at 5.1σ . the search has been extended by loosening the selection criteria in order to improve the statistical uncertai... | more results from the opera experiment |
orca (oscillations research with cosmics in the abyss) is a megaton-scale cherenkov neutrino detector currently under construction by the km3net collaboration, at a depth of 2450m in the mediterranean sea. atmospheric neutrinos cross the earth along a wide range of baselines, undergoing matter effects which enhance neu... | sensitivity of orca to the neutrino mass ordering and oscillation parameters |
papers on the searches for dark matter and exotics, neutrino oscillations and detector calibration, prepared for the 35th international cosmic ray conference (icrc 2017, busan, south korea) by the antares collaboration | the antares collaboration: contributions to icrc 2017 part iii: searches for dark matter and exotics, neutrino oscillations and detector calibration |
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