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planck data when combined with ancillary data provide a unique opportunity to separate the diffuse emission components of the inner galaxy. the purpose of the paper is to elucidate the morphology of the various emission components in the strong star-formation region lying inside the solar radius and to clarify the rela... | planck intermediate results. xxiii. galactic plane emission components derived from planck with ancillary data |
to have a more comprehensive understanding of the water ecological security status of the yellow river basin, this paper constructs a water ecological security evaluation index system founded on the pressure-state-response (psr) model. the indicators are selected by considering factors such as meteorological conditions... | water ecological security assessment and spatial autocorrelation analysis of prefectural regions involved in the yellow river basin |
superluminous supernovae (slsne) are massive star explosions that are too luminous to be powered by traditional energy sources, such as the radioactive decay of 56ni. instead, they may be powered by a central engine, such as a millisecond pulsar or magnetar, whose relativistic wind inflates a nebula of high-energy part... | gamma-ray thermalization and leakage from millisecond magnetar nebulae: toward a self-consistent model for superluminous supernovae |
the galactic center gev excess (gce) has garnered great interest as a possible signal of either dark matter annihilation or some novel astrophysical phenomenon, such as a new population of gamma-ray emitting pulsars. in a companion paper, we showed that in a 10° radius region of interest (roi) surrounding the galactic ... | the enigmatic galactic center excess: spurious point sources and signal mismodeling |
in this work, large eddy simulations (les) of a gas turbine model combustor (gtmc) are done using a five-step global mechanism that includes separate thermal and non-thermal nox formation parts. to verify the accuracy of the solution, time-averaged profiles of the flow variables and fluctuations are compared to the ava... | an investigation on flame structure and nox formation in a gas turbine model combustor using large eddy simulation |
radio pulsars show remarkable clock-like stability, which make them useful astronomy tools in experiments to test equation of state of neutron stars and detecting gravitational waves using pulsar timing techniques. a brief review of relevant astrophysical experiments is provided in this paper highlighting the current s... | precision pulsar timing with the ort and the gmrt and its applications in pulsar astrophysics |
we introduce a new method for evaluating the oscillatory integrals which describe natural interference patterns. as an illustrative example of contemporary interest, we consider astrophysical plasma lensing of coherent sources like pulsars and fast radio bursts in radio astronomy. plasma lenses are known to occur near ... | oscillatory path integrals for radio astronomy |
we calculate the sensitivity to a circular polarization of an isotropic stochastic gravitational wave background (isgwb) as a function of frequency for ground- and space-based interferometers and observations of the cosmic microwave background. the origin of a circularly polarized isgwb may be due to exotic primordial ... | sensitivity to a frequency-dependent circular polarization in an isotropic stochastic gravitational wave background |
with the doors beginning to swing open on the new gravitational wave astronomy, this review provides an up-to-date survey of the most important physical mechanisms that could lead to emission of potentially detectable gravitational radiation from isolated and accreting neutron stars. in particular we discuss the gravit... | gravitational waves from single neutron stars: an advanced detector era survey |
we explore the burst energy distribution of fast radio bursts (frbs) in the low-twist magnetar model of wadiasingh & timokhin (wt19). motivated by the power-law fluence distributions of frb 121102, we propose an elementary model for the frb luminosity function of individual repeaters with an inversion protocol that... | the fast radio burst luminosity function and death line in the low-twist magnetar model |
an association of gw190425 and frb 20190425a had been claimed recently. given the $\sim 2.5$ hour delay of the occurrence of frb 20190425a, a uniformly rotating supramassive magnetar remnant is favored. the required maximum gravitational mass of the nonrotating neutron star (ns) is $m_{\rm tov}\approx 2.77m_\odot$, whi... | mass and radius of the most massive neutron star: the probe of the equation of state and perturbative qcd |
the fermi large area telescope gamma-ray source 3fgl j2039.6-5618 contains a periodic optical and x-ray source that was predicted to be a 'redback' millisecond pulsar (msp) binary system. however, the conclusive identification required the detection of pulsations from the putative msp. to better constrain the orbital p... | einstein@home discovery of the gamma-ray millisecond pulsar psr j2039-5617 confirms its predicted redback nature |
lorentz invariance is one of the fundamental tenets of special relativity, and has been extensively tested with laboratory and astrophysical observations. however, many quantum gravity models and theories beyond the standard model of particle physics predict a violation of lorentz invariance at energies close to the pl... | astrophysical and cosmological searches for lorentz invariance violation |
tests of gravity are important to the development of our understanding of gravitation and spacetime. binary pulsars provide a superb playground for testing gravity theories. in this chapter we pedagogically review the basics behind pulsar observations and pulsar timing. we illustrate various recent strong-field tests o... | tests of classical gravity with radio pulsars |
the high-energy diffuse gamma-ray emission and neutrino emission are expected from the galactic plane, generated by hadronuclear interactions between cosmic rays (cr) and interstellar medium (ism). therefore, measurements of these diffuse emissions will provide important clues on the origin and nature of galactic crs. ... | on the origin of galactic diffuse tev-pev emission: insight from lhaaso and icecube |
we study the motion of electrically charged particles, magnetic monopoles, and magnetic dipoles around electrically and magnetically charged stringy black holes. from the analysis of the radius of the innermost stable circular orbit of electrically charged particles, we show that the electric charge q of stringy black ... | can the dynamics of test particles around charged stringy black holes mimic the spin of kerr black holes? |
we show that some or all of the inventory of r -process nucleosynthesis can be produced in interactions of primordial black holes (pbhs) with neutron stars (nss) if pbhs with masses 10-14 m⊙<mpbh<10-8 m⊙ make up a few percent or more of dark matter. a pbh captured by a ns sinks to the center of the ns and consume... | primordial black holes and r -process nucleosynthesis |
we present the results of a bayesian search for gravitational wave (gw) memory in the nanograv 12.5-yr data set. we find no convincing evidence for any gravitational wave memory signals in this data set (bayes factor = 2.8). as such, we go on to place upper limits on the strain amplitude of gw memory events as a functi... | the nanograv 12.5-year data set: search for gravitational wave memory |
the neutron star interior composition explorer observed several rotation-powered millisecond pulsars (msps) to search for or confirm the presence of x-ray pulsations. when broad and sine-like, these pulsations may indicate thermal emission from hot polar caps at the magnetic poles on the neutron star surface. we report... | nicer x-ray observations of seven nearby rotation-powered millisecond pulsars |
the hypothesis that pulsar wind nebulae (pwne) can significantly contribute to the excess of the positron (e+) cosmic-ray flux has been consolidated after the observation of a γ -ray emission at tev energies of a few degree size around geminga and monogem pwne, and at gev energies for geminga at a much larger extension... | contribution of pulsars to cosmic-ray positrons in light of recent observation of inverse-compton halos |
we consider critically the three most widely favoured pulsar radio emission mechanisms: coherent curvature emission (cce), beam-driven relativistic plasma emission (rpe), and anomalous doppler emission (ade). we assume that the pulsar plasma is 1d, streaming outwards with a bulk lorentz factor γs ≫ <γ> - 1 ≳ 1, w... | pulsar radio emission mechanisms: a critique |
pulsar timing array experiments have recently reported strong evidence for a common-spectrum stochastic process with a strain spectral index consistent with that expected of a nanohertz-frequency gravitational-wave background, but with negligible yet non-zero evidence for spatial correlations required for a definitive ... | consistency of the parkes pulsar timing array signal with a nanohertz gravitational-wave background |
the damping effect of the free-streaming neutrinos on the second order gravitational waves is investigated in detail. we solve the boltzmann equation and give the anisotropic stress induced by neutrinos to second order. the first order tensor and its coupling with scalar perturbations induced gravitational waves are co... | impact of the free-streaming neutrinos to the second order induced gravitational waves |
strong evidence of the existence of the stochastic gravitational wave background (sgwb) has been reported recently by the north american nanohertz observatory for gravitational waves, the parkes pulsar timing array, the european pulsar timing array, and the chinese pulsar timing array collaborations. the bayesian poste... | detecting new fundamental fields with pulsar timing arrays |
after nanograv, the ipta collaboration also reports a strong evidence of a stochastic gravitation wave background. this hint has very important implications for fundamental physics. with the recent ipta data release two, we attempt to search signals of light new physics. and give new constraints on the audible axion, d... | novel physics with international pulsar timing array: axionlike particles, domain walls and cosmic strings |
we study the early universe evolution of axion-like particle (alp) domain walls taking into account the effect of friction from particles in the surrounding plasma, including the case of particles in thermal equilibrium and frozen out species. we characterize the friction force from interactions within the alp effectiv... | friction on alp domain walls and gravitational waves |
it was recently found that, in certain flavors of scalar-gauss-bonnet gravity, linearly stable bald black holes can coexist with stable scalarized solutions. the transition between both can be ignited by a large nonlinear perturbation, thus the process was dubbed nonlinear scalarization, and it happens with a jump that... | effects of mass and self-interaction on nonlinear scalarization of scalar-gauss-bonnet black holes |
in the frame of gauss–bonnet gravity and in the limit of d→4, based on the fact that spherically symmetric solution derived using any of regularization schemes will be the same form as the original theory, we derive a new interior spherically symmetric solution assuming specific forms of the metric potentials that have... | anisotropic compact stars in d → 4 limit of gauss–bonnet gravity |
following the idea that a stable sexaquark state with quark content (u u d d s s ) would have gone unnoticed by experiments so far and that such a particle would be a good dark matter candidate, we investigate the possible role of a stable sexaquark in the physics of compact stars given the stringent constraints on the... | sexaquark dilemma in neutron stars and its solution by quark deconfinement |
<p id="par1">millisecond pulsars in tight binaries have recently challenged our understanding of physical processes governing the evolution of binaries and the interaction between astrophysical plasma and electromagnetic fields. transitional systems that showed changes from rotation-powered to accretion-powered s... | transitional millisecond pulsars |
context. the psr j2222−0137 binary system has a set of features that make it a unique laboratory for tests of gravity theories.aims: to fully exploit the system's potential for these tests, we aim to improve the measurements of its physical parameters, spin and orbital orientation, and post-keplerian parameters, which ... | psr j2222−0137. i. improved physical parameters for the system |
we demonstrate that next-generation cosmic microwave background spectral distortion and pulsar timing array experiments can either detect signatures of primordial black holes in the mass range o (0.1 - 1012) m⊙ , which are sourced from primordial overdensities within the standard thermal history of the universe, or con... | multimessenger probes of inflationary fluctuations and primordial black holes |
as the era of gravitational-wave astronomy has well and truly begun, gravitational radiation from rotating neutron stars remains elusive. rapidly spinning neutron stars are the main targets for continuous-wave searches since, according to general relativity, provided they are asymmetrically deformed, they will emit gra... | modelling neutron star mountains |
the radio galaxy 3c 66b has been hypothesized to host a supermassive black hole binary (smbhb) at its center based on electromagnetic observations. its apparent 1.05-year period and low redshift ($\sim0.02$) make it an interesting testbed to search for low-frequency gravitational waves (gws) using pulsar timing array (... | the nanograv 12.5-year data set: a computationally efficient eccentric binary search pipeline and constraints on an eccentric supermassive binary candidate in 3c 66b |
the recent data from nanograv provide strong evidence of the existence of the \acp{sgwb}. we investigate \acp{sigw} from finslerian inflation as a potential source of stochastic gravitational wave background. small-scale ($\lesssim$1 mpc) statistically anisotropic primordial scalar perturbations can be generated in fin... | scalar induced gravitational waves from finslerian inflation and pulsar timing arrays observations |
white dwarf stars are the most common stellar fossils. when in binaries, they make up the dominant form of compact object binary within the galaxy and can offer insight into different aspects of binary formation and evolution. one of the most remarkable white dwarf binary systems identified to date is ar scorpii (ar sc... | a 5.3-min-period pulsing white dwarf in a binary detected from radio to x-rays |
coupling of axions or axion-like particles (alps) with photons may lead to photons escaping optically opaque regions by oscillating into alps. this phenomenon may be viewed as the light shining through wall (lsw) scenario. while this lsw technique has been used previously in controlled laboratory settings to constrain ... | light shining through wall bounds on axions from obscured magnetars |
significant evidence for a stochastic gravitational-wave background has recently been reported by several pulsar timing array observations. these studies have shown that, in addition to astrophysical explanations based on supermassive black hole binaries (smbhbs), cosmological origins are considered equally important s... | on the anisotropies of the cosmological gravitational-wave background from pulsar timing array observations |
we report the properties of more than 800 bursts detected from the repeating fast radio burst (frb) source frb 20201124a with the five-hundred-meter aperture spherical radio telescope during an extremely active episode on utc 2021 september 25th-28th in a series of four papers. in this fourth paper of the series, we pr... | fast observations of an extremely active episode of frb 20201124a. iv. spin period search |
the apparent n-independence observed in the evolution of massive black hole binaries (mbhbs) in recent simulation of merging stellar bulges suggests a simple interpretation beyond complex time-dependent relaxation processes. we conjecture that the mbhb hardening rate is roughly equivalent to that of a binary immersed i... | scattering experiments meet n-body - i. a practical recipe for the evolution of massive black hole binaries in stellar environments |
the location of radio pulsars in the period-period derivative (p-\dot{p}) plane has been a key diagnostic tool since the early days of pulsar astronomy. of particular importance is how pulsars evolve through the p-\dot{p} diagram with time. here we show that the decay of the inclination angle (\dot{α }) between the mag... | pulsar braking and the p-dot{p} diagram |
we present results from the first directed search for nontensorial gravitational waves. while general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. this analysis is sensitive to continuous signals of scalar, ... | first search for nontensorial gravitational waves from known pulsars |
based on phase-resolved broadband spectroscopy using xmm-newton and nustar, we report on a potential cyclotron resonant scattering feature (crsf) at e ∼ 13 kev in the pulsed spectrum of the recently discovered ultraluminous x-ray source (ulx) pulsar ngc 300 ulx1. if this interpretation is correct, the implied magnetic ... | a potential cyclotron resonant scattering feature in the ultraluminous x-ray source pulsar ngc 300 ulx1 seen by nustar and xmm-newton |
decade-long timing observations of arrays of millisecond pulsars have placed highly constraining upper limits on the amplitude of the nanohertz gravitational-wave stochastic signal from the mergers of supermassive black hole binaries (∼10-15 strain at f = 1 yr-1). these limits suggest that binary merger rates have been... | are we there yet? time to detection of nanohertz gravitational waves based on pulsar-timing array limits |
we study the efficiency of pair production in polar caps of young pulsars under a variety of conditions to estimate the maximum possible multiplicity of pair plasma in pulsar magnetospheres. we develop a semi-analytic model for calculation of cascade multiplicity which allows efficient exploration of the parameter spac... | on the polar cap cascade pair multiplicity of young pulsars |
we perform a systematic assessment of models for the equation of state (eos) of dense matter in the context of recent neutron star mass and radius measurements to obtain a broad picture of the structure of neutron stars. we demonstrate that currently available neutron star mass and radius measurements provide strong co... | using neutron star observations to determine crust thicknesses, moments of inertia, and tidal deformabilities |
the psr j1023+0038 binary system hosts a neutron star and a low-mass, main-sequence-like star. it switches on year timescales between states as an eclipsing radio millisecond pulsar and a low-mass x-ray binary (lmxb). we present a multi-wavelength observational campaign of psr j1023+0038 in its most recent lmxb state. ... | coordinated x-ray, ultraviolet, optical, and radio observations of the psr j1023+0038 system in a low-mass x-ray binary state |
we present results from a circular polarization survey for radio stars in the rapid askap continuum survey (racs). racs is a survey of the entire sky south of δ = +41○ being conducted with the australian square kilometre array pathfinder telescope (askap) over a 288 mhz wide band centred on 887.5 mhz. the data we analy... | a circular polarization survey for radio stars with the australian ska pathfinder |
the interaction between refraction from a distribution of inhomogeneous plasma and gravitational lensing introduces novel effects to the paths of light rays passing by a massive object. the plasma contributes additional terms to the equations of motion, and the resulting ray trajectories are frequency-dependent. lensin... | frequency-dependent effects of gravitational lensing within plasma |
the fast folding algorithm (ffa) is a phase-coherent search technique for periodic signals. it has rarely been used in radio pulsar searches, having been historically supplanted by the less computationally expensive fast fourier transform (fft) with incoherent harmonic summing (ihs). here, we derive from first principl... | optimal periodicity searching: revisiting the fast folding algorithm for large-scale pulsar surveys |
the recent discovery of pulsating ultraluminous x-ray sources (ulxs) shows that the apparent luminosity of accreting neutron stars can exceed the eddington luminosity by a factor of 100s. the relation between the actual and apparent luminosity is a key ingredient in theoretical models of ulxs, but it is still under deb... | pulsating ulxs: large pulsed fraction excludes strong beaming |
nonthermal relativistic plasmas are ubiquitous in astrophysical systems like pulsar wind nebulae and active galactic nuclei, as inferred from their emission spectra. the underlying nonthermal particle acceleration (ntpa) processes have traditionally been modeled with a fokker-planck (fp) diffusion-advection equation in... | first-principles demonstration of diffusive-advective particle acceleration in kinetic simulations of relativistic plasma turbulence |
we investigate the hadron-quark phase transition in cold neutron stars in light of (i) the observed limits on the maximum-mass of heavy pulsars, (ii) constraints on the tidal properties inferred from the gravitational waves emitted in binary neutron-star mergers, and (iii) mass and radius constraints derived from the o... | delta baryons and diquark formation in the cores of neutron stars |
we analyze dispersion measure (dm) variations of 37 millisecond pulsars in the nine-year north american nanohertz observatory for gravitational waves (nanograv) data release and constrain the sources of these variations. dm variations can result from a changing distance between earth and the pulsar, inhomogeneities in ... | the nanograv nine-year data set: measurement and analysis of variations in dispersion measures |
we use compiled high-precision pulsar timing measurements to directly measure the galactic acceleration of binary pulsars relative to the solar system barycenter. given the vertical accelerations, we use the poisson equation to derive the oort limit, i.e., the total volume mass density in the galactic mid-plane. our be... | a measurement of the galactic plane mass density from binary pulsar accelerations |
aims: we investigate the extension of the very high-energy spectral tail of the crab pulsar at energies above 400 gev.methods: we analyzed ~320 h of good-quality crab data obtained with the magic telescope from february 2007 to april 2014.results: we report the most energetic pulsed emission ever detected from the crab... | teraelectronvolt pulsed emission from the crab pulsar detected by magic |
we describe the north american nanohertz observatory for gravitational waves (nanograv) and its efforts to directly detect and study gravitational waves and other synergistic physics and astrophysics using radio timing observations of millisecond pulsars. | the nanograv program for gravitational waves and fundamental physics |
we study the implications of the very recently reported mass m={2.17}-0.10+0.11 m ⊙ of psr j0740+6620 on the equation of state (eos) of super-dense neutron-rich nuclear matter with respect to existing constraints on the eos based on the mass m = 2.01 ± 0.04 m ⊙ of psr j0348+0432, the maximum tidal deformability of gw17... | implications of the mass m={2.17}_{-0.10}^{+0.11} m ⊙ of psr j0740+6620 on the equation of state of super-dense neutron-rich nuclear matter |
the square kilometre array (ska) will make ground breaking discoveries in pulsar science. in this chapter we outline the ska surveys for new pulsars, as well as how we will perform the necessary follow-up timing observations. the ska's wide field-of-view, high sensitivity, multi-beaming and sub-arraying capabilities, c... | a cosmic census of radio pulsars with the ska |
the dispersion measure (dm), the column density of free electrons to a pulsar, is shown to be frequency dependent because of multipath scattering from small-scale electron-density fluctuations. dms vary between propagation paths whose transverse extent varies strongly with frequency, yielding arrival times that deviate... | frequency-dependent dispersion measures and implications for pulsar timing |
the repeating fast radio burst (frb) localized to a globular cluster (gc) in m81 challenges our understanding of frb models. in this letter, we explore dynamical formation scenarios for objects in old gcs that may plausibly power frbs. using n-body simulations, we demonstrate that young neutron stars (nss) may form in ... | dynamical formation channels for fast radio bursts in globular clusters |
we compare the results of a large grid of n-body simulations with the surface brightness and velocity dispersion profiles of the globular clusters ω cen and ngc 6624. our models include clusters with varying stellar-mass black hole retention fractions and varying masses of a central intermediate-mass black hole (imbh).... | no evidence for intermediate-mass black holes in the globular clusters ω cen and ngc 6624 |
the main aim of this study is to explore the existence and salient features of spherically symmetric relativistic quark stars in the background of massive brans-dicke gravity. the exact solutions to the modified einstein field equations are derived for specific forms of coupling and scalar field functions using the equ... | exploring physical features of anisotropic quark stars in brans-dicke theory with a massive scalar field via embedding approach |
in this work some families of relativistic anisotropic charged fluid spheres have been obtained by solving the einstein-maxwell field equations with a preferred form of one of the metric potentials, and suitable forms of electric charge distribution and pressure anisotropy functions. the resulting equation of state (eo... | some new wyman-leibovitz-adler type static relativistic charged anisotropic fluid spheres compatible to self-bound stellar modeling |
in this work, we investigate anisotropic effects on the equations of state (eos) used to describe neutron and quark stars in the framework of rastall-rainbow gravity. all our calculations are computed using two different eos to describe the matter contained within the star: the mit bag model for quark stars and the iu-... | anisotropic compact stars in rastall-rainbow gravity |
nonequilibrium conditions imposed by neutrino cooling through the liquid-solid transition lead to disorder in the solid crust of neutron stars. disorder reduces the superfluid fraction, $\rho_s/\rho$, at densities above that of neutron drip, $\rho_d \approx 4\times 10^{11}\,g/cm^3$. for an amorphous solid crust the sup... | superfluidity in disordered neutron stars crusts |
we explore the possible mass radius relation of compact stars for the equation of states with a first order phase transition. the low density matter is described by a nuclear matter equation of state resulting from fits to nuclear properties. a constant speed of sound parametrization is used to describe the high densit... | classifications of twin star solutions for a constant speed of sound parameterized equation of state |
there are two outstanding issues regarding the neutron-star merger event gw170817: the nature of the compact remnant and the interstellar shock. the mass of the remnant of gw170817, ∼2.7 {m}⊙ , implies that the remnant could be either a massive rotating neutron star, or a black hole. we report chandra director’s discre... | gw170817 most likely made a black hole |
we have constructed a new time-scale, tt(ipta16), based on observations of radio pulsars presented in the first data release from the international pulsar timing array (ipta). we used two analysis techniques with independent estimates of the noise models for the pulsar observations and different algorithms for obtainin... | a pulsar-based time-scale from the international pulsar timing array |
the detection of gravitational waves from neutron star merger events has opened up a new field of multimessenger astronomy linking gravitational-wave events to short gamma-ray bursts and kilonova afterglows. a further - yet to be discovered - electromagnetic counterpart is a precursor emission produced by the nontrivia... | electromagnetic precursors to gravitational-wave events: numerical simulations of flaring in pre-merger binary neutron star magnetospheres |
strong magnetic fields, synchrotron emission, and compton scattering are omnipresent in compact celestial x-ray sources. emissions in the x-ray energy band are consequently expected to be linearly polarized. x-ray polarimetry provides a unique diagnostic to study the location and fundamental mechanisms behind emission ... | shedding new light on the crab with polarized x-rays |
relativistic jets are observed throughout the universe and strongly affect their surrounding environments on a range of physical scales, from galactic binary systems1 to galaxies and clusters of galaxies2. all types of accreting black hole and neutron star have been observed to launch jets3, with the exception of neutr... | an evolving jet from a strongly magnetized accreting x-ray pulsar |
gravitational waves (gws) create correlations in the arrival times of pulses from different pulsars. the expected correlation μ (γ ) as a function of the angle γ between the directions to two pulsars was calculated by hellings and downs for an isotropic and unpolarized gw background, and several pulsar timing array (pt... | variance of the hellings-downs correlation |
pulsar wind nebulae are highly intriguing astrophysical objects in many respects. they are the brightest and closest class of relativistic sources, and hence the ultimate laboratory for the physics of relativistic plasmas: several processes observed (or inferred to occur) in other classes of relativistic sources can he... | the theory of pulsar wind nebulae: recent progress |
the crab nebula is so far the only celestial object with a statistically significant detection in soft x-ray polarimetry1-4, a window that has not been explored in astronomy since the 1970s. however, soft x-ray polarimetry is expected to be a sensitive probe of magnetic fields in high-energy astrophysical objects, incl... | re-detection and a possible time variation of soft x-ray polarization from the crab |
ultra-light primordial black holes with masses m bh < 109 g evaporate before big-bang nucleosynthesis producing all matter fields, including dark matter, in particular super-heavy dark matter: m dm ≳ 1010 gev. if the dark matter gets its mass via u(1) symmetry-breaking, the phase transition that gives a mass to the ... | testing super heavy dark matter from primordial black holes with gravitational waves |
pulsar timing arrays (ptas) consisting of widely distributed and well-timed millisecond pulsars can serve as a galactic interferometer to measure gravitational waves. with the same data acquired for ptas, we propose to develop pulsar polarization arrays (ppas), to explore astrophysics and fundamental physics. as in the... | pulsar polarization arrays |
the discovery of a radioactively powered kilonova associated with the binary neutron-star merger gw170817 remains the only confirmed electromagnetic counterpart to a gravitational-wave event1,2. observations of the late-time electromagnetic emission, however, do not agree with the expectations from standard neutron-sta... | asymmetric mass ratios for bright double neutron-star mergers |
the first fast radio burst (frb) to be precisely localized was associated with a luminous persistent radio source (prs). recently, a second frb/prs association was discovered for another repeating source of frbs. however, it is not clear what makes frbs or prs or how they are related. we compile frb and prs properties ... | on the fast radio burst and persistent radio source populations |
we review electrodynamics of rotating magnetized neutron stars, from the early vacuum model to recent numerical experiments with plasma-filled magnetospheres. significant progress became possible due to the development of global particle-in-cell simulations which capture particle acceleration, emission of high-energy p... | electrodynamics of pulsar magnetospheres |
i present an empirical study of the properties of fast radio bursts (frbs): gigahertz-frequency, dispersed pulses of extragalactic origin. i focus my investigation on a sample of 17 frbs detected at the parkes radio telescope with largely self-consistent instrumentation. of this sample, six are temporally unresolved, e... | the observed properties of fast radio bursts |
we consider ultraluminous x-ray systems (ulxs) where the accretor is a neutron star rather than a black hole. we show that the recently discovered example (m82 x-2) fits naturally into the simple picture of ulxs as beamed x-ray sources fed at super-eddington rates, provided that its magnetic field is weaker (≃1011g) th... | ulxs: neutron stars versus black holes |
pulsar timing arrays (ptas) detect gravitational waves (gws) via the correlations they induce in the arrival times of pulses from different pulsars. we assume that the gws are described by a gaussian ensemble, which models the confusion noise produced by expected pta sources. the mean correlation h2μu(γ ) as a function... | hellings and downs correlation of an arbitrary set of pulsars |
context. by providing information about the location of scattering material along the line of sight (los) to pulsars, scintillation arcs are a powerful tool for exploring the distribution of ionized material in the interstellar medium (ism). here, we present observations that probe the ionized ism on scales of ~0.001-3... | a scintillation arc survey of 22 pulsars with low to moderate dispersion measures |
in the framework of the thomas-fermi approximation, we systematically study the eoss and microscopic structures of neutron star matter in a vast density range with n b ≈ 10-10-2 fm-3, where various covariant density functionals are adopted, i.e., those with nonlinear self couplings (nl3, pk1, tm1, gm1, mtvtc) and densi... | unified neutron star eoss and neutron star structures in rmf models |
the main focus of this paper is to explore the possibility of providing a new family of exact solutions for suitable anisotropic spherically symmetric systems in the realm of general relativity involving the embedding spherically symmetric static metric into the five-dimensional pseudo-euclidean space. in this regard, ... | anisotropic compact stars via embedding approach in general relativity: new physical insights of stellar configurations |
gravity theories beyond general relativity typically predict dipolar gravitational emission by compact-star binaries. this emission is sourced by "sensitivity" parameters depending on the stellar compactness. we introduce a general formalism to calculate these parameters, and show that in shift-symmetric horndeski theo... | gravitation-wave emission in shift-symmetric horndeski theories |
in present article we extend one of our earlier works bhar et al. (astrophys. space sci. 359: 13, 2015) by considering quadratic equation of state for the matter distribution. the solution has its distinct feature as the eos chosen is quadratic and is presenting for the first time in tolman vii background. the solution... | compact star modeling with quadratic equation of state in tolman vii space-time |
lorentz symmetry violations can be described by an effective field theory framework that contains both general relativity and the standard model of particle physics called the standard model extension (sme). recently, postfit analysis of gravity probe b and binary pulsars led to an upper limit at the 10-4 level on the ... | lorentz symmetry and very long baseline interferometry |
continued observation of psr j0737-3039, the double pulsar, is expected to yield a precise determination of its primary component’s moment of inertia in the next few years. since the moment of inertia depends sensitively on the neutron star’s internal structure, such a measurement will constrain the equation of state o... | constraints on the moment of inertia of psr j0737-3039a from gw170817 |
while binary pulsar systems are fantastic laboratories for a wide array of astrophysics, they are particularly difficult to detect. the orbital motion of the pulsar changes its apparent spin frequency over the course of an observation, essentially “smearing” the response of the time series in the fourier domain. we rev... | a fourier domain “jerk” search for binary pulsars |
we construct realistic sensitivity curves for pulsar timing array searches for gravitational waves, incorporating both red and white noise contributions to individual pulsar noise spectra, and the effect of fitting to a pulsar timing model. we demonstrate the method on both simulated pulsars and a realistic array consi... | realistic sensitivity curves for pulsar timing arrays |
we study the formation and evolution of topological defects in an aligned axion model with multiple peccei-quinn scalars, where the qcd axion is realized by a certain combination of the axions with decay constants much smaller than the conventional peccei-quinn breaking scale. when the underlying u(1) symmetries are sp... | topological defects and nano-hz gravitational waves in aligned axion models |
the canadian hydrogen observatory and radio-transient detector (chord) is a next-generation radio telescope, proposed for construction over the next 3-5 years, which will leverage canadian technology developments to yield breakthrough measurements of the cosmos. chord is a pan-canadian project, designed to work with an... | the canadian hydrogen observatory and radio-transient detector (chord) |
magnetic braking (mb) likely plays a vital role in the evolution of low-mass x-ray binaries (lmxbs). however, there is still uncertainty around the physics of mb, and there are various proposed scenarios for mb in the literature. to examine and discriminate the efficiency of mb, we investigate the lmxb evolution with f... | evolution of lmxbs under different magnetic braking prescriptions |
∼6% of all known pulsars have been observed to exhibit sudden spin-up events, known as glitches. for more than fifty years, these phenomena have played an important role in helping to understand pulsar (astro)physics. based on the review of pulsar glitches search method, the progress made in observations in recent year... | pulsar glitches: a review |
we describe the ongoing relativistic binary programme (relbin), a part of the meertime large survey project with the meerkat radio telescope. relbin is primarily focused on observations of relativistic effects in binary pulsars to enable measurements of neutron star masses and tests of theories of gravity. we selected ... | the relativistic binary programme on meerkat: science objectives and first results |
gravitational-wave (gw) astronomy, together with precise pulsar timing and long baseline interferometry, is changing our ability to perform tests of fundamental physics with astrophysical observations. some of these tests are based on electromagnetic (em) probes or electrically charged bodies, and assume an empty unive... | the tune of the universe: the role of plasma in tests of strong-field gravity |
we consider the current observed ensemble of pulsing ultraluminous x-ray sources (pulxs). we show that all of their observed properties (luminosity, spin period, and spin-up rate) are consistent with emission from magnetic neutron stars with fields in the usual range 10^{11}-10^{13} g, which is collimated (`beamed') by... | no magnetars in ulxs |
the timing of millisecond pulsars has long been used as an exquisitely precise tool for testing the building blocks of general relativity, including the strong equivalence principle and lorentz symmetry. observations of binary systems involving at least 1 ms pulsar have been used to place bounds on the parameters of ei... | new binary pulsar constraints on einstein-æther theory after gw170817 |
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