Context. Arp 299 is the brightest luminous infrared galaxy (LIRG) within 50 Mpc, with IR luminosity log( L ∕ ⊙ ) = 11.9. It provides a unique laboratory for testing physical processes in merging galaxies. Aims. We study first time low-frequency (~150 MHz) radio brightness distribution of at subarcsecond resolution, tracing both compact and extended emission regions local spectral energy (SED) o...