Strengthening Gravitational-Wave and Pulsar Science with the CHIME Telescope

Radio pulsars – rotating neutron stars with beamed emission observed as periodic radio pulses – are uniquely powerful tools for probing open questions in “fundamental physics.” Such questions that pulsars may answer include: are there gravitational waves (GWs) at low frequencies, perhaps from the early universe? How does matter behave in the extreme-density environments within neutron stars?

Can the effects imprinted on pulsar signals from the interstellar medium (ISM) further probe the environments and properties of neutron stars? A research team at West Virginia University will try to address these and other questions by increasing the capabilities of the NSF-funded North American Nanohertz Observatory for Gravitational Waves (NANOGrav), which uses observations of millisecond-period radio pulsars as a galaxy-sized detector of gravitational waves (GW).

The project will incorporate into NANOGrav data from the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope. Students working on the project will undertake studies of pulsar timing, ISM, and noise properties that together form the bedrock of a firm NANOGrav detection of GWs. In addition, the investigators will develop a series of open-source, educational activities regarding the searching for and timing of pulsars to help train people interested in pursuing academic study of radio pulsars.

The rotational stability of pulsars allows them to serve as precisely-ticking clocks in extreme environments where sub-microsecond-level effects predicted by Einstein’s general relativity can be resolved. Most of the key measurements in gravitational and nuclear astrophysics have come from studying pulsars and their timing properties. The recent evidence for GWs at nanohertz frequencies, recently established by NANOGrav, have shown that the “discovery space” of GW astronomy and neutron-star physics remains largely unexplored.

The proposed work leverages these facts in order to build a research program focused on low-frequency GW astronomy and, by the nature of NANOGrav analysis, high-accuracy pulsar science. The resultant studies supported by this grant proposal will: characterize the stability of pulse morphology for all NANOGrav pulsars and thus the noise properties for a GW detection; yield a large number of new neutron-star mass measurements using the maturing framework of scintillation theory; and derive new and unique

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.