Analysis of the ionized interstellar medium and orbital dynamics of PSR J1909-3744 using scintillation arcs

ABSTRACT Long-term studies of binary millisecond pulsars (MSPs) provide precise tests strong-field gravity, and can be used to measure neutron-star masses. PSR J1909-3744, a MSP has been the subject several pulsar timing analyses. The edge-on orbit enables measurement its mass using Shapiro delay; however, there is degeneracy in sense inclination angle, i, multiple solutions for longitude ascending node, Ω. Radio scintillate due inhomogeneities ionized interstellar medium (IISM). This result scintillation arcs power spectrum dynamic that use these study constrain orbits. Here, we J1909-3744 observations from 64-m Parkes Telescope (Murriyang) over ≈13 yr, techniques lower signal-to-noise regime. By monitoring annual orbital variations arc-curvature measurements, are able characterize velocity IISM. We find statistics IISM remained stationary this time slightly anisotropic model (axial ratio ≳1.2) preferred. relative distance single dominant thin scattering screen at s = 0.49 ± 0.04, or Ds 590 50 pc, with an angle anisotropy ζ 85 6° (East North) direction VIISM,ζ 14 10 km s−1. combining physical current results, also Ω 225 3° i 86.46 0.05°.