A comparison of G-band brightness as a proxy-magnetometer in various magnetic configurations

TL;DR

This study demonstrates that G-band filtergrams centered at 430.4 nm offer improved magnetic field diagnostics in the solar photosphere compared to the conventional 430.5 nm, especially in magnetized regions.

Contribution

It provides a detailed comparison of G-band filtergrams at 430.4 nm and 430.5 nm using MHD simulations, highlighting the superior diagnostic potential of the 430.4 nm filter.

Findings

Higher contrast in G-band filtergrams at 430.4 nm across magnetic environments

Enhanced sensitivity to temperature variations in magnetized regions

Potential applications in stellar magnetic activity diagnostics

Abstract

We investigate the diagnostic potential of the G-band at 430.4 nm for probing small-scale magnetic fields in the solar photosphere. Combining three-dimensional MHD simulations from the MURaM code and spectral synthesis via the RH 1.5D code, we evaluate the intensity contrast in the G-band filtergrams by comparing the filter centered at 430.4 nm in comparison to the conventional 430.5 nm. Our results show that filtergrams centered at 430.4 nm provide higher contrast across varying magnetic environments, particularly at narrow filter widths. This enhancement arises from its slightly higher formation height and greater sensitivity to temperature variations in magnetized regions. These findings indicate that G-band filtergrams centered at 430.4 nm show enhanced diagnostic potential under the assumptions of the present modeling. The obtained results are also relevant and suggest potential applications in stellar contexts, where molecular bands are often used as proxies for magnetic activity.