Star formation and gas flows in the centre of the NUGA galaxy NGC 1808 observed with SINFONI
Résumé
NGC 1808 is a nearby barred spiral galaxy which hosts young stellar clusters in a patchy circumnuclear ring with a radius of 240 pc. In order to study the gaseous and stellar kinematics and the star formation properties of the clusters, we perform seeing-limited H K-band near-infrared integral-field spectroscopy with SINFONI of the inner 600 pc. From the MBH-sigma* relation, we find a black hole mass of a few 107M&sun;. We estimate the age of the young stellar clusters in the circumnuclear ring to be ≲10 Myr. No age gradient along the ring is visible. However, the starburst age is comparable to the travel time along the ring, indicating that the clusters almost completed a full orbit along the ring during their lifetime. In the central 600 pc, we find a hot molecular gas mass of 730 M&sun; which, with standard conversion factors, corresponds to a large cold molecular gas reservoir of several 108M&sun;, in agreement with CO measurements from the literature. The gaseous and stellar kinematics show several deviations from pure disc motion, including a circumnuclear disc and signs of a nuclear bar potential. In addition, we confirm streaming motions on the 200 pc scale that have recently been detected in CO(1-0) emission. Thanks to the enhanced angular resolution of
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