LIRG sample in the SFR - M_star and sSFR - M_star planes. Left: SFR as a function of the stellar mass M_star. The solid and dashed (orange) lines indicate the location of the local MS relation and the 1σ scatter, respectively, obtained by Elbaz et al. (2007) using SDSS galaxies at z ∼ 0 and converted to Kroupa IMF, in agreement with that derived by Whitaker et al. (2012). Our LIRGs are shown according to the color code defined in Fig. 1: isolated disks (RD), (PD), interacting, and merging systems are shown in blue, magenta, green, and red, respectively. The solid lines between the points (green and black) link galaxies that belong to the same system. Galaxies containing an AGN are identified with an empty black square. The horizontal red dashed line represents the threshold SFR to reach the LIRG IR luminosity (log L_IR/L_⊙ ≥ 11). Right: specific SFR as a function of the stellar mass M_star. The three (solid, dotted, and dashed) gray lines identify the different SFR regimes (i.e., 1, 5, and 20 M_⊙ yr⁻¹, respectively). The MS relation is also shown (in orange).