Selection criteria for OFGs at z ≳ 3. Left: color-magnitude diagram for the selection of OFGs. This diagram shows the evolutionary tracks of theoretical galaxy templates at z = 2 − 6, with stellar mass log(M_⋆/M_⊙) = 10 − 11 and solar metallicity. The numbers in the circles indicate the redshift. The solid and dashed evolutionary tracks correspond to stellar masses with log(M_⋆/M_⊙) = 11 and log(M_⋆/M_⊙) = 10, respectively. These templates are based on the BC03 models (Bruzual & Charlot 2003), including an instantaneous burst (i.e., simple stellar population; SSP) model formed at z = 10 (grey area) and a non-evolving constant star formation (CSF) model with an age of 300 Myr with varying degrees of reddening (blue, green, olive, and red areas). The SSP model corresponds to a passive or old galaxy with an age of 1 Gyr at z = 3.5. The blue triangular region shows the selection criteria for H-dropouts in Wang et al. (2019), i.e., no H-band flux above 5σ (H > 27 mag; blue dashed line) and [4.5] < 24 mag (blue solid line). The red triangular region shows the selection criteria for OFGs in this work. Right: different theoretical galaxy templates in HST/F160W (H-band) and IRAC 4.5 μm filters. The templates include a passive galaxy with an age of 1 Gyr at z = 3.5 and three star-forming galaxies with different degrees of reddening at z = 4. At a similar [4.5], the three star-forming galaxies with different dust extinction values exhibit different H-band magnitudes.