  Using deep imaging from the CANDELS and HFF surveys, we present bulge+disc
decompositions with GalfitM for $\sim$17,000 galaxies over $0.2 \leq z\leq
1.5$. We use various model parameters to select reliable samples of discs and
bulges, and derive their stellar masses using an empirically calibrated
relation between mass-to-light ratio and colour. Across our entire redshift
range, we show that discs follow stellar mass-size relations that are
consistent with those of star-forming galaxies, suggesting that discs primarily
evolve via star formation. In contrast, the stellar mass-size relations of
bulges are mass-independent. Our novel dataset further enables us to separate
components into star-forming and quiescent based on their specific star
formation rates. We find that both star-forming discs and star-forming bulges
lie on stellar mass-size relations that are similar to those of star-forming
galaxies, while quiescent discs are typically smaller than star-forming discs
and lie on steeper relations, implying distinct evolutionary mechanisms.
Similar to quiescent galaxies, quiescent bulges show a flattening in the
stellar mass-size relation at $\sim$10$^{10}$M$_\odot$, below which they show
little mass dependence. However, their best-fitting relations have lower
normalisations, indicating that at a given mass, bulges are smaller than
quiescent galaxies. Finally, we obtain rest-frame colours for individual
components, showing that bulges typically have redder colours than discs, as
expected. We visually derive UVJ criteria to separate star-forming and
quiescent components and show that this separation agrees well with component
colour. HFF bulge+disc decomposition catalogues used for these analyses are
publicly released with this paper.
