Circumnuclear Shock and Starburst in NGC 6240: Near-Infrared Imaging and Spectroscopy with Adaptive Optics

Abstract

We have obtained adaptive optics, high spatial resolution (0.15"),K-band spectra and images of the region around the two active nucleiin NGC 6240, which show the presence of circumnuclear shocks. Thedata are consistent with thermal excitation being the dominant mechanismin the nuclear region. UV fluorescence and associative detachmentmay also contribute to the fraction of energy emitted through molecularhydrogen transitions. The near-IR continuum emission appears closelyassociated with the two active nuclei. The morphological similaritiesbetween the near-IR images and the Chandra X-ray images indicatethat the same mechanisms may be responsible for the emission in thenear-IR and X-ray bands.