Chandra observations of the X-ray-luminous star-forming galaxy merger ARP 299

We report the results of a Chandra observation of the X-ray-luminous star-forming galaxy Arp 299 (NGC 3690/IC 694). We detect 18 discrete X-ray sources with luminosities above similar to10(39) ergs s(-1) (0.5-8.0 keV band), which contribute similar to40% of the total galactic emission in this band. The remaining emission is associated with a diffuse component spatially coincident with regions of widespread star formation. We detect X-ray emission from both nuclei. One of the discrete sources within the complex nuclear region of NGC 3690 is found to have a very hard spectrum, and therefore we associate it with the origin of the active galactic nucleus-like spectrum that has also been detected at high X-ray energies using BeppoSAX.