Related papers: Nonlinear Orbital Variations in Binary Radio Pulsa…

We derive expressions and develop a numerical technique for the analysis of the line profile moment variations for stars pulsating in oblique non-radial modes. This represents an extension of the widely used spectroscopic moment mode…

We report on gamma-ray orbital modulation of the transitioning millisecond pulsar binary XSS J12270-4859 detected in the Fermi Large Area Telescope (LAT) data. We use long-term optical data taken with the XMM-Newton Optical Monitor and the…

We report on orbital modulation of the 100-600 MeV gamma-ray emission of the $P_{\rm B}=4.6$ hr millisecond pulsar binary PSR J2339$-$0533 using 11 yr of Fermi Large Area Telescope data. The modulation has high significance (chance…

General relativity predicts that a rotating body produces a frame-dragging (or Lense-Thirring) effect: the orbital plane of a test particle in a non-equatorial orbit precesses about the body's symmetry axis. In this paper we compute the…

Transitional millisecond pulsars are systems that alternate between an accreting low-mass X-ray binary (LMXB) state, and a non-accreting radio pulsar state. When at the LMXB state, their X-ray and optical light curves show rapid flares and…

We present an analysis of $23~$yr of pulse arrival times for PSR B1259$-$63. The pulsar is in a binary orbit about its approximately $20~M_{\odot}$ companion LS$~$2883. Our best-fitting timing solution has none of the pulse-number…

At present, 19 double neutron star (DNS) systems are detected by radio timing and 2 merging DNS systems are detected by kilo-hertz gravitational waves. Because of selection effects, none of them has an orbital period $P_b$ in the range of a…

The recent discovery of a roughly simultaneous periodic variability in the light curves of the BL Lac object PG 1553+113 at several electromagnetic bands represents the first case of such odd behavior reported in the literature. Motivated…

We present an updated timing solution and an analysis of the profile evolution - including precession and beam shape - of the young, relativistic binary pulsar J1906+0746. The 144-ms pulsar, in a 3.98-hour orbit with eccentricity 0.085…

We present the first optical polarimetric study of the two transitional pulsars PSR J1023+0038 and XSS J12270-4859. This work is focused on the search for intrinsical linear polarisation (LP) in the optical emission from the two systems. We…

Stochastic temporal wandering of the spin frequency $\nu$ of a rotation-powered pulsar (i.e.~the achromatic component of timing noise unrelated to interstellar propagation) affects the accuracy with which the secular braking torque can be…

Pulsars are famous for their rotational stability. Most of them steadily spin down and display a highly repetitive pulse shape. But some pulsars experience timing irregularities such as nulling, intermittency, mode changing and timing…

The following results of dissertation are submitted for defense: 1. Precise measurements of coordinates and proper motion of the pulsar PSR 0329+54 using the VLBI method. 2. Establishing of the reason for the discrepancy between the…

Propagation effects in the interstellar medium and intrinsic profile changes can cause variability in the timing of pulsars, which limits the accuracy of fundamental science done via pulsar timing. One of the best timing pulsars, PSR…

The parabolic structure of the secondary or conjugate spectra of pulsars is often the result of isolated one-dimensional (or at least highly anisotropic) lenses in the ISM. The curvature of these features contains information about the…

Compact binary systems emitting gravitational waves (GWs) can exhibit orbital eccentricity, along with generic spin orientations, leading to the precession of the orbital angular momentum, individual spins, and the orbital plane. While…

PSR B1937+21 was the first millisecond pulsar ever measured. Which has been appeared as a singular pulsar. The high-precision observation of this pulsar shows systemic long-term variation in the residual of time of arrivals. This paper…

Pulsar timing is a powerful tool that, by accounting for every rotation of a pulsar, precisely measures the spin frequency, spin frequency derivatives, astrometric position, binary parameters when applicable, properties of the ISM, and…

The double pulsar (PSR J0737-3039A/B) provides some of the most stringent tests of general relativity (GR) and its alternatives. The success of this system in tests of GR is largely due to the high-precision, long-term timing of its…

Pulsar's position, proper motion and parallax are important parameters in timing equations. It is a really challenging work to fit astrometric parameters accurately through pulsar timing, especially for pulsars that show irregular timing…