Disc breaks across masses and wavelengths

In addition, optical Sloan Digital Sky Survey (SDSS) or Liverpool telescope data was used for 480 of these galaxies. We find that in low-mass galaxies the single exponential profiles (Type I) are most common, and that their fraction decreases with increasing galaxy stellar mass. The fraction of down-bending (Type II) profiles increases with stellar mass, possibly due to more common occurrence of bar resonance structures.

The up-bending (Type III) profiles are also more common in massive galaxies. The observed wavelength affects the scalelength of the disc of every profile type. Especially the scalelength of the inner disc (h_i_) of Type II profiles increases from infrared to u-band on average by a factor of ~2.2.

Consistent with the previous studies, but with a higher statistical significance, we find that Type II outer disc scalelengths (h_o_) in late-type and low mass galaxies (T>4, log10(M*/M_{sun}_)<~10.5) are shorter in bluer wavelengths, possibly due to stellar radial migration populating the outer discs with older stars. In Type III profiles h_o are larger in the u band, hinting to the presence of young stellar population in the outer disc.

While the observed wavelength affects the disc parameters, it does not significantly affect the profile type classification in our sample. Our results indicate that the observed wavelength is a significant factor when determining the profile types in very low mass dwarf galaxies, for which more Type II profiles have been previously found using optical data.