# Timing observations of three Galactic millisecond pulsars

D. R. Lorimer, A. M. Kawash, P. C. C. Freire, D. A. Smith, M. Kerr, M. A. McLaughlin, M. B. Mickaliger, R. Spiewak, M. Bailes, E. Barr, M. Burgay, A. D. Cameron, F. Camilo, S. Johnston, F. Jankowski, E. F. Keane, M. Keith, M. Kramer, A. Possenti

Research output: Contribution to journalArticlepeer-review

## Abstract

We report observed and derived timing parameters for three millisecond pulsars (MSPs) from observations collected with the Parkes 64-m telescope, Murriyang. The pulsars were found during re-processing of archival survey data by Mickaliger et al. One of the new pulsars (PSR J1546-5925) has a spin period $P=7.8$ ms and is isolated. The other two (PSR J0921-5202 with $P=9.7$ ms and PSR J1146-6610 with $P=3.7$ ms) are in binary systems around low-mass ($>0.2 M_{\odot}$) companions. Their respective orbital periods are $38$.2 d and $62.8$ d. While PSR J0921-5202 has a low orbital eccentricity $e=1.3 \times 10^{-5}$, in keeping with many other Galactic MSPs, PSR J1146-6610 has a significantly larger eccentricity, $e = 7.4 \times 10^{-3}$. This makes it a likely member of a group of eccentric MSP-He white dwarf binary systems in the Galactic disk whose formation is poorly understood. Two of the pulsars are co-located with previously unidentified point sources discovered with the Fermi satellite's Large Area Telescope, but no $\gamma$-ray pulsations have been detected, likely due to their low spin-down powers. We also show that, particularly in terms of orbital diversity, the current sample of MSPs is far from complete and is subject to a number of selection biases.
Original language English 5303-5309 7 Royal Astronomical Society. Monthly Notices 507 4 2 Sep 2021 https://doi.org/10.1093/mnras/stab2474 Published - 1 Nov 2021

## Keywords

• pulsars: individual (PSR J0921-5202, PSR J1146-6610, PSR J1546-5925)
• stars: neutron

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