A universal stellar mass-size relation of galaxies in the GOODS-North region

We present scaling relations between the stellar mass (M _*) and size of galaxies at 0.3 < z < 3 for half-light (R ₅₀) and 90 percent-light (R ₉₀) radii, using a deep K-band-selected catalogue taken with the Subaru Telescope and Multi-Object Infrared Camera and Spectrograph (MOIRCS) in the Great Observatories Origins Deep Survey (GOODS)-North region. The logarithmic slope is independent of redshift in a wide mass range of M _*∼ 10 ⁸-10 ¹¹M _⊙, irrespective of galaxy populations (star forming and quiescent). The offset change is ≲50 percent. Provided that optical light in the rest frame traces the stellar mass of galaxies, the universal relation demonstrates that the stellar mass was built up in galaxies over their cosmic histories in a similar manner on average, irrespective of galaxy mass. The small offset in each stellar mass bin from the universal relation shows weak size evolution at a given mass. There is a moderate increase of 30-50 percent for R ₅₀ and R ₉₀ for less massive galaxies (M _* < 10 ¹⁰M _⊙) from z∼ 3 to 1, while the sizes remain unchanged or slightly decreased towards z∼ 0.3. For massive galaxies (M _*≳ 10 ¹¹M _⊙), the evolution increases by ∼70-80 percent in R ₉₀ from z∼ 3 to 0.3, though it is weaker in R ₅₀. The evolution of compactness factor, R ₅₀/R ₉₀, which becomes smaller at lower redshift, is suggestive of minor merging effect in the outer envelope of massive galaxies.