Resolving the Buried Starburst in Arp 299

We present new 37.7 μm far-infrared imaging of the infrared luminous (L_IR~5.16×10¹¹L_solar) interacting galaxy Arp 299 (= IC 694 + NGC 3690). We show that the 38 μm flux, like the 60 and 100 μm emission, traces the luminosity of star forming galaxies but at considerably higher spatial resolution. Our data establish that the major star formation activity of the galaxy originates from a point source in its eastern component, IC 694, which is inconspicuous in the optical, becoming visible only at the near- and mid-infrared. We find that IC 694 is 2 times more luminous than NGC 3690, contributing to more than 46% of the total energy output of the system at this wavelength. The spectral energy distribution of the different components of the system clearly shows that IC 694 has 6 times the infrared luminosity of M82, and it is the primary source responsible for the bolometric luminosity of Arp 299.