A Comparison of p-g Tidal Coupling Analyses

TL;DR

This paper examines conflicting claims about the presence of p-g tidal mode coupling in GW170817 data, clarifying that previous analyses' conclusions depend on the interpretation of posterior samples.

Contribution

It provides a detailed reanalysis of existing posterior samples, resolving discrepancies in previous studies' claims about p-g tidal effects.

Findings

Reyes & Brown's posterior samples do not disfavor p-g mode coupling.

The discrepancy arises from different interpretations of the same data.

Previous claims of disfavor are not supported by the reanalysis.

Abstract

Two recent studies have attempted to constrain the proposed $p$-$g$ tidal instability with gravitational-wave data from GW170817. The studies use Bayesian methods to compare a model that includes $p$-$g$ tidal effects with one that does not. Using the same data, they arrive at very different conclusions. Reyes & Brown find that the observations of GW170817 strongly disfavor the existence of $p$-$g$ mode coupling. However, the LIGO and Virgo Collaborations find that neither model is strongly favored. We investigate the origin of this discrepancy by analyzing Reyes & Brown's publicly available posterior samples. Contrary to their claims, we find that their samples do not disfavor $p$-$g$ mode coupling.