Scientific potential for LINC NIRVANA observations of galactic nuclei

Abstract

As a near-infrared (NIR) wide field interferometric imager offering an angular resolution of about 10 milliarcseconds LINC/NIRVANA at the Large Binocular Telescope will be an ideal instrument for imaging of galactic nuclei including the center of the Milky Way. Recent optical/IR imaging surveys can now quite successfully be used to search for star-galaxy pairs that are suitable for interferometric observation with LINC NIRVANA. These objects can then be used to efficiently investigate galaxy interaction, nuclear activity, and star formation in distant galaxies. In the NIR these investigations will be carried out at scales below 100~pc for z<0.05 and at scales below 500~pc at z<2. The Galactic Center measurements of stellar orbits and strongly variable NIR and X-ray emission from Sagittarius A* at the center of the Milky Way have provided the strongest evidence so far that the dark mass concentrations seen in many galactic nuclei are most likely super massive black holes. Observations with LINC NIRVANA will allow to simultaneously investigate the stellar dynamics of the entire central cluster, the determination of the amount of extended mass within the cusp region, and to monitor the activity of the 3 million solar mass black hole at the position of Sagittarius A* at separations of only about 10 light hours or 15 Schwarzschild radii.