Effects of granulation on the visibility of solar oscillations

TL;DR

This paper investigates how solar oscillation observations are influenced by near-surface convection, revealing significant dependencies that could improve understanding of helioseismic surface effects.

Contribution

It provides observational evidence linking local granulation intensity to variations in solar oscillation amplitude and phase.

Findings

Oscillation properties vary with local granulation intensity

Significant dependence of observed modes on convection state

Potential implications for helioseismic surface effect corrections

Abstract

Context. The interaction of solar oscillations with near surface convection is poorly understood. These interactions are likely the cause of several problems in helio- and astero-seismology, including the so-called surface effect and apparently unphysical travel time shifts as a function of center to limb distance. There is thus a clear need for further theoretical understanding and observational tests. Aims. The aim is to determine how the observed modes are affected by the convection. Methods. I use HMI velocity and intensity images to construct k-$\omega$ diagrams showing how the oscillation amplitude and phase depend on the local granulation intensity. Results. There is a clear and significant dependence of the observed properties of the oscillations on the local convection state.