Pulsar observations at low frequencies: applications to pulsar timing and solar wind models
Abstract
Efforts are underway to use high-precision timing of pulsars in order to detect low-frequency gravitational waves. A limit to this technique is the timing noise generated by dispersion in the plasma along the line of sight to the pulsar, including the solar wind. The effects due to the solar wind vary with time, influenced by the change in solar activity on different time-scales, ranging up to ∼11 yr for a solar cycle. The solar wind contribution depends strongly on the angle between the pulsar line of sight and the solar disc, and is a dominant effect at small separations. Although solar wind models to mitigate these effects do exist, they do not account for all the effects of the solar wind and its temporal changes. Since low-frequency pulsar observations are most sensitive to these dispersive delays, they are most suited to test the efficacy of these models and identify alternative approaches. Here, we investigate the efficacy of some solar wind models commonly used in pulsar timing using long-term, high-cadence data on six pulsars taken with the Long Wavelength Array, and compare them with an operational solar wind model. Our results show that stationary models of the solar wind correction are insufficient to achieve the timing noise desired by pulsar timing experiments, and we need to use non-stationary models, which are informed by other solar wind observations, to obtain accurate timing residuals.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 04, 2022
- Source ID
- 10.1093/mnras/stac316
Entities
People
- Greg Taylor
- Jayce Dowell
- K. Stovall
- Prashanth Kumar
- Susan White
Organizations
- Air Force Office of Scientific Research
- Air Force Research Laboratory
- National Centers for Environmental Information
- National Oceanic and Atmospheric Administration
- National Science Foundation
- Office of Naval Research
- University of New Mexico