Improving Distances to Binary Millisecond Pulsars with Gaia

Abstract

Pulsar distances are notoriously difficult to measure, and play an important role in many fundamental physics experiments, such as pulsar timing arrays (PTAs). Here we perform a cross-match between International PTA pulsars (IPTA) and Gaia's DR2 and DR3. We then combine the IPTA pulsar's parallax with its binary companion's parallax, found in Gaia, to improve the distance measurement to the binary. We find 7 cross-matched IPTA pulsars in Gaia DR2, and when using Gaia DR3, we find 6 IPTA pulsar cross-matches, but with 7 Gaia objects. Moving from Gaia DR2 to Gaia DR3, we find that the Gaia parallaxes for the successfully cross-matched pulsars improved by $53\%$, and pulsar distances improved by $29\%$. Finally, we find that binary companions with a $<3.0\sigma$ detection are unreliable associations, setting a high bar for successful cross-matches.