Dr. Oleg Tsupko
Projects & Publications
In space, there are objects exhibiting very high gravitational energy: black holes and neutron stars. In such objects, a large mass is concentrated in a small region of space, which gives rise to strong gravitational fields. An effect of these fields is that light rays that pass close by these objects, or that are emitted by them, move along curved paths. This affects the image of the object that a distant observer detects: we perceive them in unusual, distorted ways. An amazing example of such an object is what is known as the black hole shadow: a very specific dark silhouette of a black hole which was recently observed in the galaxy M87. By studying the properties of this image, we can draw conclusions about the properties of the distant object itself. In my project, I intend to focus on situations in which compact objects are surrounded by plasma. Plasma is
a dispersive medium, and in this case “rainbow effects” may be observed, caused by light rays of different frequencies that are deflected by it at different angles. In other words, gravitating objects surrounded by plasma act like refractive prisms, splitting light into its spectral colors. In my project, I will investigate how properties of such objects and their environments can be deduced from their appearance to the distant observer.