What if you have a black hole impostor without an event horizon? We calculated how it looks, for the example of a "Boson star". You get a shadow, but there are characteristic differences in the plasma properties. Olivares et al. (2020) @ERC_Researchhttps://t.co/1e5NlJYkYX pic.twitter.com/V4JMASmuUl

— Heino Falcke (@hfalcke) August 18, 2020