Timing and scintillation of a young Galactic halo pulsar

TL;DR

This study combines timing and scintillation observations of pulsar PSR J1740+1000 to measure its proper motion, velocity, and scattering environment, revealing a likely pulsar wind nebula influence on scintillation patterns.

Contribution

First measurement of proper motion for PSR J1740+1000, linking its velocity to Galactic halo origin, and detailed scintillation analysis indicating PWN-dominated scattering.

Findings

Proper motion of 56.9 mas/yr with velocity 329 km/s.

Detection of scintillation arcs and arclets.

Scattering likely dominated by pulsar wind nebula.

Abstract

We present a timing and scintillation study of the young Galactic halo pulsar PSR J1740+1000 using observations from the Nanshan, FAST, and Parkes radio telescopes. From timing analysis, we measure the pulsar's proper motion for the first time, indicating motion away from the Galactic plane at a position angle of 16.7 +/- 4.8 degrees (Galactic coordinates), with a total proper motion of 56.9 +/- 8.0 mas/yr and a corresponding transverse velocity of 329 +/- 80 km/s. This velocity suggests that PSR J1740+1000 is a typical-velocity young pulsar born within the Galactic halo. In scintillation studies, we detect scintillation arcs, arclets, and double-layered adjacent arcs in the secondary spectra. Under isotropic and anisotropic scattering assumptions, the screen-to-pulsar distance is 370 +/- 72 pc and 1 +/- 12 pc, respectively. The latter closely matches the scale of the pulsar wind nebula associated with PSR J1740+1000 and provides a better fit, suggesting that scattering is likely dominated by the PWN. The double-layered adjacent arcs observed on MJD 60180 imply that the pulsar's scattered image consists of two dominant components (A and B) and multiple weaker components. Component A is located at the pulsar's geometric position (0 uas), while Component B is located 112 +/- 16 uas and 23 +/- 17 uas from the central component under isotropic and anisotropic scattering, respectively. The frequency-independent angular position of Component B hints at refraction by an AU-scale structure within the scattering region, possibly originating from the PWN.