# Correcting for the solar wind in pulsar timing observations: the role of simultaneous a nd l ow-frequency observations

## TL;DR

This paper investigates how simultaneous low-frequency and wide-bandwidth observations can improve correction of solar wind effects in pulsar timing, which is crucial for gravitational wave detection.

## Contribution

It demonstrates that a single wide-bandwidth receiver can effectively model and remove solar wind effects, highlighting limitations for pulsars near the Sun.

## Key findings

- Wide-bandwidth receivers can model solar wind effects.
- Single observations may be insufficient near the Sun.
- Two-telescope observations are often inadequate for close-passing pulsars.

## Abstract

The primary goal of the pulsar timing array projects is to detect ultra-low-frequency gravitational waves. The pulsar data sets are affected by numerous noise processes including varying dispersive delays in the interstellar medium and from the solar wind. The solar wind can lead to rapidly changing variations that, with existing telescopes, can be hard to measure and then remove. In this paper we study the possibility of using a low frequency telescope to aid in such correction for the Parkes Pulsar Timing Array (PPTA) and also discuss whether the ultra-wide-bandwidth receiver for the FAST telescope is sufficient to model the solar wind variations. Our key result is that a single wide-bandwidth receiver can be used to model and remove the effect of the solar wind. However, for pulsars that pass close to the Sun such as PSR J1022+1022, the solar wind is so variable that observations at two telescopes separated by a day are insufficient to correct the solar wind effect.