GBT20A-570

Measuring the Mass of the Binary Pulsar J0218+4232

Abstract

We request 15 hours for a concentrated observing campaign targeting the part of the orbit of PSR J0218+4232 when the pulsar is in superior conjunction. Existing long-term timing data from multiple instruments have allowed us to detect the relativistic Shapiro delay, which peaks at superior conjunction. However, the properties of this data set mean we can only get an imprecise estimate of the pulsar mass: 1.7+/-0.5 Msun. The proposed observations will allow us to get a better measurement of the Shapiro delay, and shrink the uncertainty of the pulsar mass. J0218+4232 may contain a massive pulsar; its properties make it almost the twin of the binary system J0740+6620 which contains the most massive neutron star currently known: 2.14 (+0.10/-0.09) Msun. Precise measurements of high pulsar masses are required in order to constrain the NS equation of state. (This is a DDT proposal in response to the special call for filler proposals in the 2020A semester.)

Investigators

Name	Institution
Julia Deneva *	Naval Research Laboratory
Paul Ray	Naval Research Laboratory
Matthew Kerr	Naval Research Laboratory
Andrea Lommen	Franklin and Marshall College
Scott Ransom	National Radio Astronomy Observatory; Virginia, University of

* indicates the PI