The MSPSR$\pi$ catalogue: VLBA astrometry of 18 millisecond pulsars

H. Ding , A.T. Deller , B.W. Stappers , T.J.W. Lazio , D. Kaplan , S. Chatterjee , W. Brisken , J. Cordes , P.C.C. Freire , E. Fonseca , I. Stairs , L. Guillemot (1, 2) , A. Lyne , Ismaël Cognard (2, 1) , D.J. Reardon , Gilles Theureau (2, 1, 3)

1 USN - Unité Scientifique de la Station de Nançay
2 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
3 LUTH (UMR_8102) - Laboratoire Univers et Théories

With unparalleled rotational stability, millisecond pulsars (MSPs) serve as ideal laboratories for numerous astrophysical studies, many of which require precise knowledge of the distance and/or velocity of the MSP. Here, we present the astrometric results for 18 MSPs of the "MSPSR$\pi$" project focusing exclusively on astrometry of MSPs, which includes the re-analysis of 3 previously published sources. On top of a standardized data reduction protocol, more complex strategies (i.e., normal and inverse-referenced 1D interpolation) were employed where possible to further improve astrometric precision. We derived astrometric parameters using sterne, a new Bayesian astrometry inference package that allows the incorporation of prior information based on pulsar timing where applicable. We measured significant ($>3\,\sigma$) parallax-based distances for 15 MSPs, including $0.81\pm0.02\,$kpc for PSR J1518+4904 -- the most significant model-independent distance ever measured for a double neutron star system. For each MSP with a well-constrained distance, we estimated its transverse space velocity and radial acceleration. Among the estimated radial accelerations, the updated ones of PSR J1012+5307 and PSR J1738+0333 impose new constraints on dipole gravitational radiation and the time derivative of Newton's gravitational constant. Additionally, significant angular broadening was detected for PSR J1643-1224, which offers an independent check of the postulated association between the HII region Sh 2-27 and the main scattering screen of PSR J1643-1224. Finally, the upper limit of the death line of $\gamma$-ray-emitting pulsars is refined with the new radial acceleration of the hitherto least energetic $\gamma$-ray pulsar PSR J1730-2304.

Domaines: Astrophysique [astro-ph]; Relativité Générale et Cosmologie Quantique [gr-qc]

H. Ding, A.T. Deller, B.W. Stappers, T.J.W. Lazio, D. Kaplan, et al.. The MSPSR$\pi$ catalogue: VLBA astrometry of 18 millisecond pulsars. Monthly Notices of the Royal Astronomical Society, 2023, 519 (4), pp.4982-5007. ⟨10.1093/mnras/stac3725⟩. ⟨hal-03925284⟩