New constraints on the kinematic, relativistic, and evolutionary properties of the PSR J1757−1854 double neutron star system

• Published in: Monthly notices of the Royal Astronomical Society Vol. 523; no. 4; pp. 5064 - 5085
• Main Authors: Cameron, A D, Bailes, M, Champion, D J, Freire, P C C, Kramer, M, McLaughlin, M A, Ng, C, Possenti, A, Ridolfi, A, Tauris, T M, Wahl, H M, Wex, N
• Format: Journal Article
• Language: English
• Published: Oxford University Press 22.06.2023
• Subjects: binaries: close; gravitation; pulsars: individual: PSR J1757−1854; stars: neutron
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stad1712

ABSTRACT PSR J1757−1854 is one of the most relativistic double neutron star binary systems known in our Galaxy, with an orbital period of $P_\text{b}=4.4\, \text{h}$ and an orbital eccentricity of e = 0.61. As such, it has promised to be an outstanding laboratory for conducting tests of relativistic gravity. We present the results of a 6-yr campaign with the 100-m Green Bank and 64-m Parkes radio telescopes, designed to capitalize on this potential. We identify secular changes in the profile morphology and polarization of PSR J1757−1854, confirming the presence of geodetic precession and allowing the constraint of viewing geometry solutions consistent with General Relativity. We also update PSR J1757−1854’s timing, including new constraints of the pulsar’s proper motion, post-Keplerian parameters, and component masses. We conclude that the radiative test of gravity provided by PSR J1757−1854 is fundamentally limited to a precision of 0.3 per cent due to the pulsar’s unknown distance. A search for pulsations from the companion neutron star is also described, with negative results. We provide an updated evaluation of the system’s evolutionary history, finding strong support for a large kick velocity of $w\ge 280\, \rm{km\,s}^{-1}$ following the second progenitor supernova. Finally, we reassess PSR J1757−1854’s potential to provide new relativistic tests of gravity. We conclude that a 3-σ constraint of the change in the projected semimajor axis ($\dot{x}$) associated with Lense–Thirring precession is expected no earlier than 2031. Meanwhile, we anticipate a 3-σ measurement of the relativistic orbital deformation parameter δθ as soon as 2026.