Observations of the Galactic Centre Circumnuclear Disk with FIFI-LS
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Beschreibung
The inner few 100 pc of the Milky Way’s Galactic Centre serve as a rich laboratory for the study of star formation in extreme environments, and provide the unique opportunity to observe the workings of a galactic nucleus at high resolution. Among the most pressing questions concerning the Galactic Centre is the “Paradox of Youth” – the issue of how the dense Nuclear Stellar Cluster (NSC) of early-type stars around Sgr A* formed within the last 10 Myr. If these stars formed in-situ, then the closest candidate site is the Circumnuclear Disk (CND), which appears as a clumpy ring, inclined along the line of sight, surrounding the NSC with an inner radius of 1.5 pc. The current multiwavelength and multiscale picture of the Galactic Centre as a star formation and ISM processing engine is examined, and several episodic patterns that well fit the ensemble of measurements and models of the region are identified. From this, several key open issues are established, along with observation goals that can be achieved through the use of far-infrared spectroscopy. The strategic and operational challenges involved in planning, executing and analysing observations in the far-infrared aboard an airborne observatory are outlined. Motivated by the aforementioned open issues, observations using the Far Infrared Field-Imaging Line Spectrometer (FIFI-LS) on board the Stratospheric Observatory for Infrared Astronomy (SOFIA) are presented. These comprise spatially resolved maps of 11 far-infrared emission lines of the region with an angular resolution approximately 4 times higher than previous published data. Together, these lines span a range of tracers of the atomic, molecular and ionised gas phases. With the use of PDR modelling and several data analysis techniques, inferences on the role of the CND in the formation of the NSC are made, allowing it to be placed it in the context of the episodic Galactic Centre.
Autor*in
Aaron Bryant
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