Timing and Scintillation of a Young Galactic Halo Pulsar

Abstract We conducted a timing and scintillation study of a young Galactic halo pulsar, PSR J1740+1000, using observations from the Nanshan, FAST, and Parkes radio telescopes. From a timing analysis, we measured the proper motion of this pulsar for the first time. The proper motion measurement indicates that the pulsar is moving away from the Galactic plane at a position angle of 16 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>°</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 7 ± 4 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>°</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 8 (in Galactic coordinates), with a total proper motion of 56.9 ± 8.0 mas yr −1 and a corresponding transverse velocity of 329 ± 80 km s −1 . This velocity suggests that PSR J1740+1000 is a typical-velocity, young pulsar born within the Galactic halo. For scintillation, we detected scintillation arcs, arclets, and double-layered adjacent arcs in the secondary spectra. Under the isotropic and anisotropic scattering cases, the screen-to-pulsar distance is 370 ± 72 and 1 ± 12 pc, respectively. The latter value closely matches the scale of the pulsar wind nebula (PWN) associated with PSR J1740+1000 and provides a better fit, suggesting that its scattering is most 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), along with multiple weaker components. Component A is located at the pulsar’s geometric position with an angular position of 0 μ as, while Component B is located 112 ± 16 and 23 ± 17 μ as away from the central component under the isotropic and anisotropic scattering cases, respectively. Since the angular position of Component B is independent of observing frequency, this hints at refraction by an au-scale structure located within the scattering region, which may originate from the PWN.