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Axions could be a component of the dark matter and are of great interest forparticle physics. If present, their interaction with magnetic fields in thesolar photosphere should produce a polarization signal of real photons, whoseamplitude depends quadratically on the magnetic field strength. I search forpossible traces of axion-induced low-energy polarization signal in the visiblewavelength range near 630 nm. I use an observation of a sunspot and the nearbyactive region to study the dependence of the continuum polarization signal onmagnetic field strength. I correct the continuum polarization signal for thepolarization introduced by the telescope due to oblique reflections. Ireproduce the corrected polarization spectra using a spectral synthesis ofsolar model atmospheres that include the Zeeman effect. These synthetic spectraserve as a reference for the amount of polarization from a known source. I findno trace of an enhanced polarization signal in continuum polarization above apolarization level of around 0.05 % of I_c. I provide a weak upper limit forthe existence and interaction of axions with solar magnetic fields by proposingthat any model of solar axion generation and interaction should not lead topolarization effects above 0.05 % of the continuum intensity at a wavelength of630 nm, i.e., not more than 5 out of 10000 photons should show polarization dueto axion-related processes. Using estimates of photon and axion flux rates, Iderive an upper limit of $g_{a\gamma} < 700*10^{-10}$ GeV$^{-1}$ for theaxion-photon coupling constant $g_{a\gamma}$.

A weak upper limit for axion-related continuum polarization signal at 630 nm