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<p id="par1">understanding the physics of rotation-powered millisecond pulsars (msps) presents a number of challenges compared to that of the non-recycled pulsar population. even though their fast rotation rates can produce high spin-down power<index-term id="iterm1"><term>spin-down power</term>... | the emission physics of millisecond pulsars |
the millisecond pulsar psr j1713+0747 has undergone a distinct change in the shape of its pulse profile. using data from the fast telescope, in combination with the kunming 40 meter radio telescope and telescopes of the european pulsar timing array (nrt, effelsberg, srt, lovell and leap) we have determined that the eve... | a sustained pulse shape change in psr j1713+0747 possibly associated with timing and dm events |
we present a timing and glitch analysis of the young x-ray pulsar psr j0537-6910, located within the large magellanic cloud, using 13 yr of data from the now-decommissioned rossi x-ray timing explorer. rotating with a spin period of 16 ms, psr j0537-6910 is the fastest-spinning and most energetic young pulsar known. it... | the glitches and rotational history of the highly energetic young pulsar psr j0537-6910 |
in an accreting x-ray pulsar, a neutron star accretes matter from a stellar companion through an accretion disk. the high magnetic field of the rotating neutron star disrupts the inner edge of the disc, funneling the gas to flow onto the magnetic poles on its surface. hercules x-1 is in many ways the prototypical x-ray... | x-ray polarization reveals the precessions of the neutron star in hercules x-1 |
we describe the signatures of a circularly polarized gravitational-wave background on the timing residuals obtained with pulsar-timing arrays. most generally, the circular polarization will depend on the gravitational-wave direction, and we describe this angular dependence in terms of spherical harmonics. while the amp... | chirality of the gravitational-wave background and pulsar-timing arrays |
we investigate the influence of a specific class of slow baryon number violation (bnv) -- one that induces quasi-equilibrium evolution -- on pulsar spin characteristics. this work reveals how bnv can potentially alter observable parameters, including spin-down rates, the second derivative of spin frequency, and braking... | pulsar timing anomalies: a window into baryon number violation |
in this work, we made an extensive study about the possible presence of anisotropies in strange stars. to accomplish this task, we use three different configurations for the strange matter: the unpaired matter, a two-flavor super-conducting (2sc) strange matter, and a fully three-flavor super-conducting strange matter ... | spherically symmetric anisotropic strange stars |
recent advances in numerical algorithms and computational power have enabled first-principles simulations of pulsar magnetospheres using particle-in-cell techniques. these ab initio simulations seem to indicate that pair creation through photon-photon collision at the light cylinder is required to sustain the pulsar en... | filling the magnetospheres of weak pulsars |
chain inflation is an alternative to slow-roll inflation in which the inflaton tunnels along a large number of consecutive minima in its potential. in this work we perform the first comprehensive calculation of the gravitational wave spectrum of chain inflation. in contrast to slow-roll inflation the latter does not st... | the gravitational wave spectrum of chain inflation |
we explore the phenomenological consequences of breaking discrete global symmetries in quantum gravity (qg). we extend a previous scenario where discrete global symmetries are responsible for scalar dark matter (dm) and domain walls (dws), to the case of fermionic dm, considered as a feebly interacting massive particle... | quantum gravity effects on fermionic dark matter and gravitational waves |
we consider an inflationary kinetic function with an integrable pole that is traversed during inflation. this scenario leads to enhanced spectra of primordial scalar inhomogeneities with detectable signals: formation of primordial black holes (that could explain dark matter) and scalar-induced gravitational waves (that... | traversing a kinetic pole during inflation: primordial black holes and gravitational waves |
some fast-moving pulsars, such as the guitar and the lighthouse, exhibit asymmetric non-thermal emission features that extend well beyond their ram pressure confined pulsar wind nebulae (pwne). based on our 3d relativistic simulations, we analytically explain these features as kinetically streaming pulsar wind particle... | kinetic `jets' from fast-moving pulsars |
we report on a search for radio transients at 340 mhz with the jansky very large array low-band ionosphere and transient experiment (vlite). between 2015 july 29 and september 27, operating in commensal mode, vlite imaged approximately 2800 pointings covering 12,000 deg2 on the sky, sampling timescales ranging from ten... | exploring the transient radio sky with vlite: early results |
the use of pulsars as astrophysical clocks for gravitational wave (gw) experiments demands the highest possible timing precision. pulse times of arrival (toas) are limited by stochastic processes that occur in the pulsar itself, along the line of sight through the interstellar medium, and in the measurement process. on... | the nanograv nine-year data set: noise budget for pulsar arrival times on intraday timescales |
pairs of active galactic nuclei (agn) are observational flags of merger-driven smbh growth, and represent an observable link between galaxy mergers and gravitational wave (gw) events. thus, studying these systems across their various evolutionary phases can help quantify the role mergers play in the growth of smbhs as ... | tracking smbh mergers from kpc to sub-pc scales with axis |
the most massive globular cluster in our galaxy, omega centauri, is an interesting target for pulsar searches, because of its multiple stellar populations and the intriguing possibility that it was once the nucleus of a galaxy that was absorbed into the milky way. the recent discoveries of pulsars in this globular clus... | meerkat discovery of 13 new pulsars in omega centauri |
ray tracing plays a vital role in black hole imaging, modeling the emission mechanisms of pulsars, and deriving signatures from physics beyond the standard model. in this work we focus on one specific application of ray tracing, namely, predicting radio signals generated from the resonant conversion of axion dark matte... | generalized ray tracing for axions in astrophysical plasmas |
we describe ixpe polarization observations of the pulsar wind nebula (pwn) msh 15-52, the "cosmic hand." we find x-ray polarization across the pwn, with b-field vectors generally aligned with filamentary x-ray structures. high-significance polarization is seen in arcs surrounding the pulsar and toward the end of the "j... | the polarized cosmic hand: ixpe observations of psr b1509-58/msh 15-52 |
we present bskg3, the latest entry in the brussels-skyrme-on-a-grid series of large-scale models of nuclear structure based on an energy density functional. compared to its predecessors, the new model offers a more realistic description of nucleonic matter at the extreme densities relevant to neutron stars. this achiev... | skyrme-hartree-fock-bogoliubov mass models on a 3d mesh: iii. from atomic nuclei to neutron stars |
in this work, we investigate the relativistic structure of compact stars within the framework of f(q) gravity, where q is the nonmetricity scalar. in particular, we focus on the f(q) = αq + β gravity model, with α and β being free parameters of the theory. this study is split up into: 1. models of dark energy stars by ... | dark energy stars and quark stars within the context of f(q) gravity |
recent observations of ver j2227+608 reveal a broken power γ-ray spectrum with the spectral index increasing from ∼1.8 in the gev energy range to ∼2.3 in the tev range. such a spectral break can be attributed to radiative energy loss of energetic electrons in the leptonic scenario for the γ-ray emission, which, in comb... | hadronic versus leptonic models for γ-ray emission from ver j2227+608 |
black widow and redback systems are compact binaries in which a millisecond pulsar heats and may even ablate its low-mass companion by its intense wind of relativistic particles and radiation. in such systems, an intrabinary shock can form as a site of particle acceleration and associated nonthermal emission. we model ... | x-ray through very high energy intrabinary shock emission from black widows and redbacks |
in this work, we use the equation of state (eos) of the (2 +1 )-flavor nambu-jona-lasinio (njl) model to study the structure of the strange quark star. with a new free parameter α , the lagrangian is constructed by two parts, the original njl lagrangian and the fierz transformation of it, as l =(1 -α )lnjl+α lfierz . t... | strange quark stars within proper time regularized (2 +1 )-flavor njl model |
recent measurements of cosmic-ray electron and positron spectra at energies from a gev to 5 tev, as well as radio, x-ray and a wide range of gamma-ray observations of pulsar-wind nebulae, indicate that pulsars are significant sources of high-energy cosmic-ray electrons and positrons. here, we calculate the local cosmic... | studying the milky way pulsar population with cosmic-ray leptons |
in this work we consider strange stars formed by quark matter in the color-flavor-locked (cfl) phase of color superconductivity. the cfl phase is described by a nambu-jona-lasinio model with four-fermion vector and diquark interaction channels. the effect of the color superconducting medium on the gluons are incorporat... | tidal deformability of strange stars and the gw170817 event |
variations of the dispersion measures (dm) and rotation measures (rm) of fast radio bursts (frbs) 121102 indicate magnetic fields ∼3-17 mg in the dispersing plasma. the electron density may be ${\sim}10^4\,$ cm-3. the observed time scales ∼1 yr constrain the size of the plasma cloud. increasing dm excludes simple model... | the environment of frb 121102 and possible relation to sgr/psr j1745-2900 |
neutron stars (nss) in scalar-tensor (st) theories of gravitation can acquire scalar charges and generate distinct spacetimes from those in general relativity (gr) through the celebrated phenomenon of spontaneous scalarization. taking on an st theory with the mass term of the scalar field, we determine the theory param... | strong-field effects in massive scalar-tensor gravity for slowly spinning neutron stars and application to x-ray pulsar pulse profiles |
the detection of a stochastic background of low-frequency gravitational waves by pulsar-timing and astrometric surveys will enable tests of gravitational theories beyond general relativity. these theories generally permit gravitational waves with non-einsteinian polarization modes, which may propagate slower than the s... | subluminal stochastic gravitational waves in pulsar-timing arrays and astrometry |
context. psr j1910−5959a is a binary millisecond pulsar in a 0.837 day circular orbit around a helium white dwarf (hewd) companion. the position of this pulsar is 6.3 arcmin (∼74 core radii) away from the optical centre of the globular cluster (gc) ngc 6752. given the large offset, the association of the pulsar with th... | psr j1910-5959a: a rare gravitational laboratory for testing white dwarf models |
we report the detection of x-ray pulsations from the rotation-powered millisecond-period pulsars psr j0740+6620 and psr j1614-2230, two of the most massive neutron stars known, using observations with the neutron star interior composition explorer (nicer). we also analyze x-ray multi-mirror mission (xmm-newton) data fo... | nicer detection of thermal x-ray pulsations from the massive millisecond pulsars psr j0740+6620 and psr j1614-2230 |
doppler anisotropies, induced by our relative motion with respect to the source rest frame, are a guaranteed property of stochastic gravitational wave backgrounds of cosmological origin. if detected by future pulsar timing array measurements, they will provide interesting information on the physics sourcing gravitation... | kinematic anisotropies and pulsar timing arrays |
neutral hydrogen (hi) is the fundamental component of the interstellar medium. the galactic plane pulsar snapshot (gpps) survey is designed for hunting pulsars by using the five-hundred-meter aperture spherical radio telescope (fast) from the visible galactic plane within ∣b∣≤ 10°. the survey observations are conducted... | peering into the milky way by fast: i. exquisite hi structures in the inner galactic disk from the piggyback line observations of the fast gpps survey |
we report on observations of psr b1508 + 55's scintillation at the effelsberg 100-m telescope spanning from early 2020 to early 2022. in the autumn of 2020, close to the time the pulsar was predicted to cross echoes in its pulse profile, a sudden transition in the scintillation arcs from peculiar stripe-like features t... | double-lens scintillometry: the variable scintillation of pulsar b1508 + 55 |
in this work, a modified nambu-jona-lasinio (njl) model with proper-time regularization is employed to study the properties of hypothetical nonstrange quark stars. the coupling constant of the four-fermion interaction in the conventional njl model is modified as g =g1+g2⟨ψ ¯ ψ ⟩ to highlight the feedback of the quark p... | study of nonstrange quark stars within a modified njl model |
pulsar timing is a technique that uses the highly stable spin periods of neutron stars to investigate a wide range of topics in physics and astrophysics. pulsar timing arrays (ptas) use sets of extremely well-timed pulsars as a galaxy-scale detector with arms extending between earth and each pulsar in the array. these ... | pulsar timing array experiments |
we present detailed timing and spectral analyses of the transient x-ray pulsar rx j0209.6-7427 in the small magellanic cloud during its 2019 giant outburst. with a better known distance than most galactic x-ray pulsars, its peak luminosity is determined to be (1.11 ± 0.06) × 1039 erg s-1; it is thus a bona fide pulsati... | fan-beamed x-ray emission from 1 to above 130 kev from the ultraluminous x-ray pulsar rx j0209.6-7427 in the small magellanic cloud |
spectral lag of the low-energy photons with respect to the high-energy ones is a common astrophysical phenomenon (such as gamma-ray bursts and the crab pulsar) and may serve as a key probe to the underlying radiation mechanism. however, spectral lag in kev range of the magnetar bursts has not been systematically studie... | discovery of the linear energy dependence of the spectral lag of x-ray bursts from sgr j1935+2154 |
annual variations of interstellar scintillation can be modelled to constrain parameters of the ionized interstellar medium. if a pulsar is in a binary system, then investigating the orbital parameters is possible through analysis of the orbital variation of scintillation. in observations carried out from 2011 to 2020 b... | periodic interstellar scintillation variations of psrs j0613-0200 and j0636+5128 associated with the local bubble shell |
x persei is a persistent low-luminosity x-ray pulsar of period of ≈ 835 s in a be binary system. the field strength at the neutron star surface is not known precisely, but indirect signs indicate a magnetic field above 1013 g, which makes the object one of the most magnetized known x-ray pulsars. here we present the re... | x-ray polarimetry of x-ray pulsar x persei: another orthogonal rotator? |
with axions now a primary candidate for dark matter, understanding their indirect astrophysical signatures is of paramount importance. key to this is the production of photons from axions in magnetised astrophysical plasmas. while simple formulae for axion-photon mixing in 1d have been sketched several decades ago, the... | axion-photon conversion in 3d media and astrophysical plasmas |
the population of radio pulsars is observed to demonstrate certain polarization properties not explained by the conventional picture of pulsar polarization, namely frequency evolution of polarization, deviations of the linear polarization angle from a curve of geometric origins, and the presence of features in the circ... | pulsar polarization: a partial-coherence model |
the detections of four apparently young radio pulsars in the milky way globular clusters are difficult to reconcile with standard neutron star formation scenarios associated with massive star evolution. here, we discuss formation of these young pulsars through white dwarf mergers in dynamically old clusters that have u... | connecting the young pulsars in milky way globular clusters with white dwarf mergers and the m81 fast radio burst |
understanding the natal kicks received by neutron stars (nss) during formation is a critical component of modelling the evolution of massive binaries. natal kicks are an integral input parameter for population synthesis codes, and have implications for the formation of double ns systems and their subsequent merger rate... | an observationally derived kick distribution for neutron stars in binary systems |
magnetic fields in the ionized medium of the disk and halo of the milky way impose faraday rotation on linearly polarized radio emission. we compare two surveys mapping the galactic faraday rotation, one showing the rotation measures of extragalactic sources seen through the galaxy, and one showing faraday depth of the... | structure in the magnetic field of the milky way disk and halo traced by faraday rotation |
we present baseband radio observations of the millisecond pulsar j1909 - 3744, the most precisely timed pulsar, using the meerkat telescope as part of the meertime pulsar timing array campaign. during a particularly bright scintillation event the pulsar showed strong evidence of pulse mode changing, among the first mil... | mode changing in j1909 - 3744: the most precisely timed pulsar |
the search for pulsars in a sample of pulsar candidates found based on a multi-year survey conducted with low (six channels; sampling 0.1s) time-frequency resolution on declinations -9° < δ < +42° was carried out with the large phased array of the lebedev physical institute (lpa lpi). lpa is a transit telescope o... | pushchino multibeam pulsar search - i. targeted search of weak pulsars |
we present a framework for modeling astrophysical pulses from radio pulsars and fast radio bursts (frbs). this framework, called fitburst, generates synthetic representations of dynamic spectra that are functions of several physical and heuristic parameters; the heuristic parameters can nonetheless accommodate a vast r... | modeling the morphology of fast radio bursts and radio pulsars with fitburst |
context. accretion onto magnetic neutron stars results in x-ray spectra that often exhibit a cyclotron resonance scattering feature (crsf) and, sometimes, higher harmonics of it. two places are suspect for the formation of a crsf: the surface of the neutron star and the radiative shock in the accretion column.aims: her... | cyclotron line formation by reflection on the surface of a magnetic neutron star |
we investigate systematically the quark-hadron mixed phase in dense stellar matter and its influence on compact star structures. the properties of quark matter and hadronic matter are fixed based on various model predictions. beside adopting constant values, the surface tension σ for the quark-hadron interface is estim... | systematic study on the quark-hadron mixed phase in compact stars |
pulsar timing array (pta) experiments are becoming increasingly sensitive to gravitational waves (gws) in the nanohertz frequency range, where the main astrophysical sources are supermassive black hole binaries (smbhbs), which are expected to form following galaxy mergers. some of these individual smbhbs may power acti... | multi-messenger approaches to supermassive black hole binary detection and parameter estimation: implications for nanohertz gravitational wave searches with pulsar timing arrays |
we develop a new theoretical model describing the formation of the radiation spectrum in accretion-powered x-ray pulsars as a result of bulk and thermal comptonization of photons in the accretion column. the new model extends the previous model developed by the authors in four ways: (1) we utilize a conical rather than... | a generalized analytical model for thermal and bulk comptonization in accretion-powered x-ray pulsars |
recently ligo collaboration discovered gravitational waves [1] predicted 100 years ago by a. einstein. moreover, in the key paper reporting about the discovery, the joint ligo & virgo team presented an upper limit on graviton mass such as mg < 1.2 × 10-22 ev [2] (see also more details in another ligo paper [3] d... | constraining the range of yukawa gravity interaction from s2 star orbits ii: bounds on graviton mass |
fast radio bursts (frbs) are millisecond-duration, luminous radio transients of extragalactic origin. these events have been used to trace the baryonic structure of the universe using their dispersion measure (dm) assuming that the contribution from host galaxies can be reliably estimated. however, contributions from t... | a fast radio burst localized at detection to a galactic disk using very long baseline interferometry |
the extended nebulae formed as pulsar winds expand into their surroundings provide information about the composition of the winds, the injection history from the host pulsar, and the material into which the nebulae are expanding. observations from across the electromagnetic spectrum provide constraints on the evolution... | pulsar wind nebulae |
there have been significant developments in the period estimation tools and methods for analysing high energy pulsars in the past few decades. however, these tools lack well-standardised methods for calculating uncertainties in period estimation and other recovered parameters for poisson--dominated data. error estimati... | quantifying period uncertainty in x-ray pulsars with poisson-limited data |
we construct new effective interactions using the relativistic mean-field models with the isoscalar- and isovector-meson mixing, σ2δ2 and ωμωμρνρν. taking into account the particle flow data in heavy-ion collisions, the observed mass of psr j0740+6620, and the tidal deformability of a neutron star from the binary merge... | can the prex-2 and crex results be understood by relativistic mean-field models with the astrophysical constraints? |
in this paper we obtain a new static and spherically symmetric model of compact star whose spacetime satisfies karmarkar's condition (1948). the einstein's field equations are solved by employing a physically reasonable choice of the metric coefficient g_{rr} so that the obtained solution is free from central singulari... | solutions of the einstein's field equations with anisotropic pressure compatible with cold star model |
mems (micro electro mechanical system) gyroscopes have been widely applied to various fields, but mems gyroscope random drift has nonlinear and non-stationary characteristics. it has attracted much attention to model and compensate the random drift because it can improve the precision of inertial devices. this paper ha... | modeling and compensation of random drift of mems gyroscopes based on least squares support vector machine optimized by chaotic particle swarm optimization |
the heps plans to adopt on-axis injection scheme because the dynamic aperture of machine is not large enough for off-axis injection for its baseline 7ba lattice design. a couple sets of strip-line kicker and fast pulser of ±15 kv amplitude, 15 ns pulse bottom width are needed for bunch spacing of 10 ns to minimize pert... | strip-line kicker and fast pulser r&d for the heps on-axis injection system |
fermi large area telescope data reveal an excess of gev gamma rays from the direction of the galactic center and bulge. several explanations have been proposed for this excess including an unresolved population of millisecond pulsars (msps) and self-annihilating dark matter. it has been claimed that a key discriminant ... | consistency between the luminosity function of resolved millisecond pulsars and the galactic center excess |
this document describes a code to perform parameter estimation and model selection in targeted searches for continuous gravitational waves from known pulsars using data from ground-based gravitational wave detectors. we describe the general workings of the code and characterise it on simulated data containing both nois... | a nested sampling code for targeted searches for continuous gravitational waves from pulsars |
if millisecond pulsars (msps) are responsible for the excess gamma-ray emission observed from the region surrounding the galactic center, the same region should also contain a large population of low-mass x-ray binaries (lmxbs). in this study, we compile and utilize a sizable catalog of lmxbs observed in the the milky ... | low mass x-ray binaries in the inner galaxy: implications for millisecond pulsars and the gev excess |
few statistically compelling correlations are found in pulsar timing data between the size of a rotational glitch and the time to the preceding glitch (backward waiting time) or the succeeding glitch (forward waiting time), except for a strong correlation between sizes and forward waiting times in psr j0537-6910. this ... | size-waiting-time correlations in pulsar glitches |
we monitor established and putative redback millisecond pulsars (msps) in time-series photometry, repeatedly covering their 5-6 hr orbital light curves in r‧ or r. on timescales of months, psr j1048+2339 and xmmu j083850.38-282756.8 exhibit similar variability of ≈0.3 mag on the heated side of the companion star. howev... | variable heating and flaring of three redback millisecond pulsar companions |
a number of low-mass millisecond pulsar (msp) binaries in their rotation-powered state exhibit double-peaked x-ray orbital modulation centered at inferior pulsar conjunction. this state, which has been known to persist for years, has recently been interpreted as emission from a shock that enshrouds the pulsar. however,... | pressure balance and intrabinary shock stability in rotation-powered-state redback and transitional millisecond pulsar binary systems |
the population of young, non-recycled pulsars with spin-down energies $\dot{e} \gt 10^{35}$ erg s-1 is sampled predominantly at γ-ray and radio wavelengths. a total of 137 such pulsars are known, with partial overlap between the sources detectable in radio and γ-rays. we use a very small set of assumptions in an attemp... | the galactic population and properties of young, highly energetic pulsars |
we have used the nanshan 25 m radio telescope at xinjiang astronomical observatory to obtain timing observations of 87 pulsars from 2002 july to 2014 march. using the "cholesky" timing analysis method we have determined positions and proper motions for 48 pulsars, 24 of which are improved positions compared to previous... | results of 12 yr of pulsar timing at nanshan. i. |
we present a general relativistic (gr) model of jet variability in active galactic nuclei due to orbiting blobs in helical motion along a funnel or cone-shaped magnetic surface anchored to the accretion disk near the black hole. considering a radiation pressure driven flow in the inner region, we find that it stabilize... | kinematics of and emission from helically orbiting blobs in a relativistic magnetized jet |
recently we have proposed a novel method to probe primordial gravitational waves from upper bounds on the abundance of primordial black holes (pbhs). when the amplitude of primordial tensor perturbations generated in the early universe is fairly large, they induce substantial scalar perturbations due to their second-or... | primordial black holes as a novel probe of primordial gravitational waves. ii. detailed analysis |
in the presence of massive bosonic degrees of freedom, rotational superradiance can trigger an instability that spins down black holes. this leads to peculiar gravitational-wave signatures and distribution in the spin-mass plane, which in turn can impose stringent constraints on ultralight fields. here, we demonstrate ... | superradiance in rotating stars and pulsar-timing constraints on dark photons |
thermal x-ray emission from rotation-powered pulsars is believed to originate from localized `hotspots' on the stellar surface occurring where large-scale currents from the magnetosphere return to heat the atmosphere. light-curve modelling has primarily been limited to simple models, such as circular antipodal emitting... | x-ray light curves from realistic polar cap models: inclined pulsar magnetospheres and multipole fields |
in the last decade, the relativistic magnetohydrodynamic (mhd) modelling of pulsar wind nebulae, and of the crab nebula in particular, has been highly successful, with many of the observed dynamical and emission properties reproduced down to the finest detail. here, we critically discuss the results of some of the most... | multi-d magnetohydrodynamic modelling of pulsar wind nebulae: recent progress and open questions |
we describe the history, methods, tools, and challenges of using pulsars to detect gravitational waves. pulsars act as celestial clocks detecting gravitational perturbations in space-time at wavelengths of light-years. the field is poised to make its first detection of nanohertz gravitational waves in the next 10 years... | pulsar timing arrays: the promise of gravitational wave detection |
observations of psr b0943+10 with xmm-newton and the lofar, lwa, and arecibo radio telescopes in 2014 november confirm the synchronous x-ray/radio switching between a radio-bright (b) mode and a radio-quiet (q) mode, in which the x-ray flux is a factor ∼2.4 higher than in the b-mode. we discovered x-ray pulsations duri... | a deep campaign to characterize the synchronous radio/x-ray mode switching of psr b0943+10 |
searches for millisecond-duration, dispersed single pulses have become a standard tool used during radio pulsar surveys in the last decade. they have enabled the discovery of two new classes of sources: rotating radio transients and fast radio bursts. however, we are now in a regime where the sensitivity to single puls... | single-pulse classifier for the lofar tied-array all-sky survey |
we present first results for faraday rotation of compact polarized sources (1-2 ghz continuum) in the h i/oh/recombination line (thor) survey of the inner galaxy. in the galactic longitude range 39° < ℓ < 52°, we find rotation measures (rms) in the range -310 rad m-2 ≤ rm ≤ +4219 rad m-2, with the highest values ... | strong excess faraday rotation on the inside of the sagittarius spiral arm |
it has been widely argued that type-i superluminous supernovae (slsne-i) are driven by powerful central engines with a long-lasting energy injection after the core-collapse of massive progenitors. one of the popular hypotheses is that the hidden engines are fast-rotating pulsars with a magnetic field of b ∼ 1013-1015 g... | radio emission from embryonic superluminous supernova remnants |
symmetries play important roles in modern theories of physical laws. in this paper, we review several experimental tests of important symmetries associated with the gravitational interaction, including the universality of free fall for self-gravitating bodies, time-shift symmetry in the gravitational constant, local po... | tests of gravitational symmetries with radio pulsars |
we have collected and analyzed the complete archive of xmm-newton (116), chandra (151), and rxte (952) observations of the small magellanic cloud (smc), spanning 1997-2014. the resulting observational library provides a comprehensive view of the physical, temporal, and statistical properties of the smc pulsar populatio... | a comprehensive library of x-ray pulsars in the small magellanic cloud: time evolution of their luminosities and spin periods |
in this paper we report on ∼ 10 yr of observations of psr j2051-0827, at radio frequencies in the range 110-4032 mhz. we investigate the eclipse phenomena of this black widow pulsar using model fits of increased dispersion and scattering of the pulsed radio emission as it traverses the eclipse medium. these model fits ... | long-term variability of a black widow's eclipses - a decade of psr j2051-0827 |
we present new observations of the c-band continuum emission and masers to assess high-mass (>8 {m}⊙ ) star formation at early evolutionary phases in the inner 200 pc of the central molecular zone (cmz) of the galaxy. the continuum observation is complete to free-free emission from stars above 10-11 {m}⊙in 91% of th... | a census of early-phase high-mass star formation in the central molecular zone |
the construction of accurate and consistent initial data for various binary parameters is a critical ingredient for numerical relativity simulations of the compact binary coalescence. in this article, we present an upgrade of the pseudospectral uc(sgrid) code, which enables us to access even larger regions of the binar... | constructing binary neutron star initial data with high spins, high compactnesses, and high mass ratios |
the direct detection of gravitational waves now provides a new channel for testing gravity theories. despite that the parametrized post-einsteinian framework is a powerful tool to quantitatively investigate the effects of modifications to gravity theory, the gravitational waveform in this framework is still extendable.... | testing massive-field modifications of gravity via gravitational waves |
the very long baseline interferometry (vlbi) technique offers angular resolutions superior to any other instruments at other wavelengths, enabling unique science applications of high-resolution imaging of radio sources and high-precision astrometry. the east asia vlbi network (eavn) is a collaborative effort in the eas... | capabilities and prospects of the east asia very long baseline interferometry network |
certain physical quantities that characterize neutron stars and quark stars (e.g. their mass, spin angular momentum, and quadrupole moment) have recently been found to be interrelated in a manner that is approximately insensitive to their internal structure. such approximately universal relations are useful to break de... | i-love-q anisotropically: universal relations for compact stars with scalar pressure anisotropy |
we have explored exact solutions free from any physical and geometrical singularities, as well as the existence of compact stellar systems throughout linear and starobinsky- f(r , t) - gravity theory. as we generally well-known, the general exact solutions of the altered einstein field equations (efes) in the backgroun... | physical properties of class i compact star model for linear and starobinsky - f(r , t) functions |
rare earth elements (ree) include the lanthanide series elements (la, ce, pr, nd, pm, sm, eu, gd, tb, dy, ho, er, tm, yb, and lu) plus sc and y. currently these metals have become very critical to several modern technologies ranging from cell phones and televisions to led light bulbs and wind turbines. this article sum... | rare earth elements: a review of applications, occurrence, exploration, analysis, recycling, and environmental impact |
magic is a system of two imaging atmospheric cherenkov telescopes located in the canary island of la palma, spain. during summer 2011 and 2012 it underwent a series of upgrades, involving the exchange of the magic-i camera and its trigger system, as well as the upgrade of the readout system of both telescopes. we use o... | the major upgrade of the magic telescopes, part ii: a performance study using observations of the crab nebula |
we present the first catalog of tev gamma-ray sources realized with data from the newly completed high altitude water cherenkov observatory (hawc). it is the most sensitive wide field-of-view tev telescope currently in operation, with a one-year survey sensitivity of ∼5%-10% of the flux of the crab nebula. with an inst... | the 2hwc hawc observatory gamma-ray catalog |
this paper presents and discusses algorithms, hardware, and software architecture developed by the team costar (collaborative subterranean autonomous robots), competing in the darpa subterranean challenge. specifically, it presents the techniques utilized within the tunnel (2019) and urban (2020) competitions, where co... | nebula: quest for robotic autonomy in challenging environments; team costar at the darpa subterranean challenge |
language models (lms) can be directed to perform target tasks by using labeled examples or natural language prompts. but selecting examples or writing prompts for can be challenging--especially in tasks that involve unusual edge cases, demand precise articulation of nebulous preferences, or require an accurate mental m... | eliciting human preferences with language models |
we present our new atacama large millimeter/submillimeter array (alma) observations targeting [o iii]88 μm, [c ii]158 μm, [n ii]122 μm, and dust-continuum emission for three lyman break galaxies at z = 6.0293-6.2037, identified in the subaru/hyper suprime-cam survey. we clearly detect [o iii] and [c ii] lines from all ... | large population of alma galaxies at z > 6 with very high [o iii] 88 μm to [c ii] 158 μm flux ratios: evidence of extremely high ionization parameter or pdr deficit? |
the crab nebula is the brightest tev gamma-ray source in the sky and has been used for the past 25 years as a reference source in tev astronomy, for calibration and verification of new tev instruments. the high altitude water cherenkov observatory (hawc), completed in early 2015, has been used to observe the crab nebul... | observation of the crab nebula with the hawc gamma-ray observatory |
we use integral field spectroscopy from the phangs-muse survey, which resolves the ionised interstellar medium structure at ∼50 pc resolution in 19 nearby spiral galaxies, to study the origin of the diffuse ionised gas (dig). we examine the physical conditions of the diffuse gas by first removing morphologically define... | a tale of two digs: the relative role of h ii regions and low-mass hot evolved stars in powering the diffuse ionised gas (dig) in phangs-muse galaxies |
for some decades now, nanotechnology has been touted as the 'next big thing' with potential impact comparable to the steam, electricity or internet revolutions -- but has it lived up to these expectations? while advances in top-down nanolithography, now reaching 10-nm resolution, have resulted in devices that are rapid... | the nanotechnology of life-inspired systems |
when a star is tidally disrupted by a supermassive black hole (smbh), roughly half of its mass falls back to the smbh at super-eddington rates. as this gas is tenuously gravitationally bound and unable to cool radiatively, only a small fraction fin ≪ 1 may accrete, with the majority instead becoming unbound in an outfl... | a bright year for tidal disruptions |
we present photometric and spectroscopic data for sn 2022joj, a nearby peculiar type ia supernova (sn ia) with a fast decline rate ($\rm{\delta m_{15,b}=1.4}$ mag). sn 2022joj shows exceedingly red colors, with a value of approximately ${b-v \approx 1.1}$ mag during its initial stages, beginning from $11$ days before m... | sn 2022joj: a potential double detonation with a thin helium shell |
we report on the highest energy photons from the crab nebula observed by the tibet air shower array with the underground water-cherenkov-type muon detector array. based on the criterion of a muon number measured in an air shower, we successfully suppress 99.92% of the cosmic-ray background events with energies e >10... | first detection of photons with energy beyond 100 tev from an astrophysical source |
we present tev gamma-ray observations of the crab nebula, the standard reference source in ground-based gamma-ray astronomy, using data from the high altitude water cherenkov (hawc) gamma-ray observatory. in this analysis we use two independent energy estimation methods that utilize extensive air shower variables such ... | measurement of the crab nebula spectrum past 100 tev with hawc |
forthcoming observational facilities will make the exploration of the early universe routine, likely probing large populations of galaxies at very low metallicities. it will therefore be important to have diagnostics that can solidly identify and distinguish different classes of objects in such low metallicity regimes.... | diagnostics for popiii galaxies and direct collapse black holes in the early universe |
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