This book will provide a broad observational overview of the center of the Milky Way. This will highlight connections with current observations of the surrounding Milky Way galaxy and other galaxy centers, and facilitate future comparisons between these research areas by presenting a comprehensive summary of the properties and structure of the Milky Way’s central regions.
The book will be divided into three main sections, which will focus on views of the Galactic center at different size scales. It will begin with the big picture: why galaxy centers are unique and interesting, and what we know (and still do not know) about them. The next section will focus on spatially-resolved observations of the central ~1000 light years (300 parsecs) of the Milky Way, a region where the properties of the stars and gas become notably different than the typical conditions in the Milky Way disk. The final section will deal with the central ~5 light years, the region in which the gravitational influence of the black hole dominates over that of the stars and gas. This section will focus on following the structure of the stars and gas down to the smallest scales that we can observe, and end with an overview of current observational methods for probing the properties of the black hole itself.