Regularized OSIRIS 3D spectroscopy at the circumnuclear disk ionization front

Abstract

AbstractThe Galactic central black hole and the central cluster of young stars are surrounded by a clumpy gas disk (the circumnuclear disk, CND) that rotates about them at a distance of ≃ 1 pc. The gas in this warm, turbulent, magnetized disk is ultimately likely to migrate into the central cavity and fuel future star formation and black hole accretion. We have observed two fields of approximately 20″ × 20″ in the CND at NIR wavelengths with the OSIRIS integral-field spectrometer at Keck Observatory. These two fields are located at the interface between the neutral and the ionized regions. Our data cover two H2 lines as well as the Brγ line of the Hi spectrum. The signal-to-noise ratio per spatial pixel of each line varies considerably across the field and becomes quite low in some regions. In order to avoid degrading the spatial resolution, we have developed a novel three-dimensional method to analyze the data in terms of regularized parameter maps. The method proves very efficient in retrieving all the information contained in the spectral line emission while not degrading the spatial resolution. We present this new method to analyze 3D spectroscopic data and describe our preliminary results on the structure of the ionized-neutral interface.