Central kiloparsec of Nearby galaxies

The Active Galactic Nuclei (AGN) gain their luminosity from accretion of matter onto a supermassive black hole. What drives the matter to the center to ignite this activity, and how the AGN influences its host galaxy, are still open questions. The NUclei of GAlaxies (NUGA) project investigates the central kiloparsec of nearby galaxies to understand these feeding and feedback processes. We contribute to the NUGA project by observing several nearby galaxies in near-infrared (NIR) regime. The main tool we employ is the integral-field spectroscopy, which is ideal for understanding the distribution and dynamics of the gas and stars, providing a combination of image and spectra of the objects. In the NIR wavelength region it is possible to observe the line emission of several species that trace ionized and partially ionized gas from starburst and shocked regions. We can also detect absorption lines which trace the stellar populations and their kinematics. The comparison of gas and stellar velocity maps reveal irregularities in the kinematics and helps us finding streaming motions and outflows. Our results, in combination to the corresponding high-resolution ALMA observations, are essential to understand the gas and stellar dynamics in the center of galaxies and provide clues on their evolution.

Figure caption: We studied the central kiloparsec of NGC 1808, a nearby spiral-barred galaxy, using SINFONI. The flux distribution of ionized hydrogen reveals a star-forming ring close to the nucleus and the false-color map provide information about the age gradient in this ring. The line of sight velocity (LOSV) maps investigate the gas and stellar kinematics, revealing irregularities due to streaming motions.