Date of Completion

Spring 5-1-2023

Project Advisor(s)

Chiara Mingarelli, Masha Gordina, Jonathan Trump

University Scholar Major

Physics

Second University Scholar Major

Applied Mathematical Sciences

Disciplines

Cosmology, Relativity, and Gravity | Other Astrophysics and Astronomy | Stars, Interstellar Medium and the Galaxy

Abstract

We have conducted a cross match of objects in Gaia Early Data Release 3 and millisecond pulsars (MSPs) in the International Pulsar Timing Array’s Data Release 2 (IPTA DR2) to identify binary systems. Gaia has parallax measurements for these optical companions, which we combine with pulsar timing based parallax measurements to calculate new combined MSP distances. Through this crossmatch with IPTA DR2 we improved five distance measurements and found the first parallax measurement for one MSP.

Using this Gaia crossmatch method now with a well-timed subset of the Australia Telescope National Facility’s database, we found three new pulsar distances. We use only pulsars which are so precisely timed that the time derivatives of their binary periods have been measured. This change is in part the result of the relative acceleration between Earth and the pulsar. When measurements of the pulsar’s proper motion and distance are available, it is possible to isolate this effect and measure the galactic acceleration at the pulsar’s position. Thus by employing the Gaia cross match to find new pulsar distances, we make it possible to find more measurements of galactic acceleration.

We have created a data release of these acceleration values for 31 pulsars and mapped the data in three dimensions. This includes all stable pulsars which have measured orbital period derivatives, distances, and proper motions in the galaxy. We validate the data with an analysis of a simple local acceleration model and find the local acceleration gradient. The results indicate a local disk density of 0.062-0.034+0.026 solar masses per cubic parsec.

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