Pulsar Timing Noise from Brownian Motion of the Sun

TL;DR

This paper suggests that the Brownian motion of the Sun caused by gravitational interactions with small asteroids introduces pulsar timing noise, which could affect the interpretation of gravitational wave signals in PTA data.

Contribution

It identifies a previously overlooked source of timing noise from asteroid-induced solar motion, emphasizing the need for improved asteroid modeling in PTA analyses.

Findings

Asteroid interactions cause solar Brownian motion affecting pulsar timing.

Timing noise from asteroids can account for up to 20% of the PTA signal.

Better asteroid mass modeling is necessary for accurate gravitational wave detection.

Abstract

Recently, Pulsar Timing Arrays (PTAs) reported a signal at nanohertz frequencies consistent with a stochastic gravitational wave background. Here, I show that the Brownian motion of the Sun as a result of its random gravitational interactions with the cluster of thousands of unmodeled Main-belt asteroids of diameters <80km, combined with small inaccuracies in the estimated masses of larger asteroids, introduces timing noise for pulsars which is up to 20% of the reported signal at frequencies of ~1/(few-years). The asteroid contribution needs to be modeled better in order to obtain accurate inferences from the PTA signal.