Fig. 3.
Sketch showing an observation of a source consisting of a linear superposition of multiple components. In this scenario, the overall profile shown on the left will be the combination of a line in emission (3e), another in absorption against the background source (2a), and a third (1) partially overlapping the background source and therefore observed in both emission (1e) and absorption (1a). See text in Sect. 3.3.2 for details.
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