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

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 centred at 430.4 nm in comparison to the conventional 430.5 nm. Our results show that filtergrams centred 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 centred at 430.4 nm show enhanced diagnostic potential under the assumptions of the present modelling. The obtained results are also relevant and suggest potential applications in stellar contexts, where molecular bands are often used as proxies for magnetic activity.