Two Millisecond Pulsars Discovered by the PALFA Survey and a Shapiro Delay Measurement

TL;DR

This paper reports the discovery of two millisecond pulsars by the PALFA survey, with detailed timing measurements including a Shapiro delay detection in one system, enabling precise mass and orbital parameter determinations.

Contribution

The study presents new millisecond pulsar discoveries and provides the first measurement of the Shapiro delay in one system, enhancing understanding of pulsar masses and testing general relativity.

Findings

Discovered two millisecond pulsars with precise timing.

Detected Shapiro delay in one pulsar, enabling mass measurements.

Measured pulsar and companion masses with uncertainties.

Abstract

We present two millisecond pulsar discoveries from the PALFA survey of the Galactic plane with the Arecibo telescope. PSR J1955+2527 is an isolated pulsar with a period of 4.87 ms, and PSR J1949+3106 has a period of 13.14 ms and is in a 1.9-day binary system with a massive companion. Their timing solutions, based on 4 years of timing measurements with the Arecibo, Green Bank, Nan\c{c}ay and Jodrell Bank telescopes, allow precise determination of spin and astrometric parameters, including precise determinations of their proper motions. For PSR J1949+3106, we can clearly detect the Shapiro delay. From this we measure the pulsar mass to be 1.47(+0.43/-0.31) solar masses, the companion mass to be 0.85(+0.14/-0.11) solar masses and the orbital inclination to be i = 79.9(+1.6/-1.9) degrees, where uncertainties correspond to +/- 1-\sigma\ confidence levels. With continued timing, we expect to also be able to detect the advance of periastron for the J1949+3106 system. This effect, combined with the Shapiro delay, will eventually provide very precise mass measurements for this system and a test of general relativity.