  Magnetic topological materials are a class of compounds with the underlying
interplay of nontrivial band topology and magnetic spin configuration.
Extensive interests have been aroused due to their application potential
involved with an array of exotic quantum states. With angle-resolved
photoemission spectroscopy and first-principles calculations, here we study the
electronic properties of two magnetic Weyl semimetal candidates PrAlSi and
SmAlSi. Though the two compounds harbor distinct magnetic ground states
(ferromagnetic and antiferromagnetic for PrAlSi and SmAlSi, respectively) and
4$f$ shell fillings, we find that they share quite analogous low-energy band
structure. By the measurements across the magnetic transitions, we further
reveal that there is no evident evolution of the band structure in both
compounds and the experimental spectra can be well reproduced by the
nonmagnetic calculations, together suggesting a negligible effect of the
magnetism on their electronic structures and a possibly weak coupling between
the localized 4$f$ electrons and the itinerant conduction electrons. Our
results offer essential insights into the interactions between magnetism,
electron correlations, and topological orders in the $R$Al$X$ ($R$ = light rare
earth and $X$ = Si or Ge) family.
