This paper presents the first detection of Shapiro delay from the binary millisecond pulsar PSR J1811-2405. We report a 11-σ measurement of the orthometric amplitude, h3=6.8(6)x10−7, and a 16-σ measurement of the orthometric ratio, ς= 0.81(5). Given the relatively high orbital inclination, i= 79(2) deg, of this binary system, we obtain constraints on the companion mass of mc= 0.31+0.08−0.06M⊙. The pulsar mass is currently less well constrained, with a value of 2.0+0.8−0.5M⊙. The companion mass and the orbital period are in agreement with the prediction made by previous numerical calculations of the evolution of compact binary systems. From a study of the polarization, we find that the orbital inclination angle is ~100 deg and that PSR J1811-2405 is an orthogonal rotator. In addition, the μs-level timing precision together with its narrow profile make PSR J1811-2405 a good candidate for inclusion in the pulsar timing arrays being used to detect nHz Gravitational waves.
@article{arxiv.2002.01009,
title = {Shapiro delay in PSR~J1811$-$2405},
author = {C. Ng and L. Guillemot and P. C. C. Freire and M. Kramer and D. J. Champion and I. Cognard and G. Theureau and E. D. Barr},
journal= {arXiv preprint arXiv:2002.01009},
year = {2020}
}