Timing of Five PALFA-Discovered Millisecond Pulsars

We report the discovery and timing results for five millisecond pulsars (MSPs) from the Arecibo PALFA survey: PSRs J1906+0055, J1914+0659, J1933+1726, J1938+2516, and J1957+2516. Timing observations of the five pulsars were conducted with the Arecibo and Lovell telescopes for time spans ranging from 1.5 to 3.3 years. All of the MSPs except one (PSR J1914+0659) are in binary systems with low eccentricities. PSR J1957+2516 is likely a redback pulsar, with a $\sim 0.1\,{M}_{\odot }$ companion and possible eclipses that last ~10% of the orbit. The position of PSR J1957+2516 is also coincident with a near-infrared source. All five MSPs are distant ($\gt 3.1$ kpc) as determined from their dispersion measures, and none of them show evidence of γ-ray pulsations in a fold of Fermi Gamma-Ray Space Telescope data. These five MSPs bring the total number of MSPs discovered by the PALFA survey to 26 and further demonstrate the power of this survey in finding distant, highly dispersed MSPs deep in the Galactic plane

Polarimetry of the Eclipsing Pulsar PSR J1748-2446A

© 2018. The American Astronomical Society. All rights reserved.. Observations with the Parkes radio telescope of the eclipsing millisecond binary pulsar PSR J1748-2446A, which is in the globular cluster Terzan 5, are presented. These include the first observations of this pulsar in the 3 GHz frequency band, along with simultaneous observations in the 700 MHz band, and new observations around 1400 MHz. We show that the pulsar signal is not eclipsed in the 3 GHz band and observe the known eclipses in the lower-frequency bands. We find that the observed pulse signal becomes depolarized during particular orbital phases and postulate that this depolarization occurs because of rotation-measure fluctuations resulting from turbulence in the stellar wind responsible for the eclipses