GBT21B-352

Hunting the Pulsar in a Unique Compact Binary

Abstract

We have discovered a new low-mass X-ray binary located within the error ellipse of the Fermi-LAT gamma-ray source 4FGL J1120.0-2204. The presumed X-ray and optical counterpart shows emission consistent with a rare type of binary: a millisecond pulsar being orbited by a companion in an intermediate stage of becoming an extremely-low-mass white dwarf. If confirmed, this system is the first of its kind, providing new insights on the late stages of the millisecond pulsar recycling process and the formation of canonical millisecond pulsar binaries. Here we request 1.0 hr of GBT time (as part of our dedicated buy-in time (PI: P. Pay)) to detect the suspected radio pulsar primary, which will confirm the nature of the system and allow us to understand the origin of this intriguing binary.

Investigators

Name	Institution
Samuel Swihart *	Michigan State University; Naval Research Laboratory
Paul Ray	Naval Research Laboratory
Julia Deneva	Naval Research Laboratory
Megan DeCesar	George Mason University

* indicates the PI