If It Looks Like a Duck, Walks Like a Duck, Is It a Duck?

          @misc{ pirsa_PIRSA:24090186,
            doi = {10.48660/24090186},
            url = {https://pirsa.org/24090186},
            author = {Giri, Suvendu},
            keywords = {Strong Gravity},
            language = {en},
            title = {If It Looks Like a Duck, Walks Like a Duck, Is It a Duck?},
            publisher = {Perimeter Institute},
            year = {2024},
            month = {sep},
            note = {PIRSA:24090186 see, \url{https://pirsa.org}}
          }
          

Abstract

The detection of gravitational waves by the Ligo-Virgo-Kagra collaboration, and the remarkable images produced by the EHT collaboration have opened new avenues into the study of highly compact objects in our universe. While observations suggest these objects are black holes, they don't rule out other possibilities. Black holes, however, create paradoxes that challenge well-established physical principles, leading to growing interest in horizonless ultra-compact objects — often called "black hole mimickers."   To understand mimickers, we need concrete, well-motivated models that are both feasible and astrophysically relevant — something that's currently scarce. In this talk, I will present a class of mimickers that we’ve been exploring: “AdS black shells,” which may provide a promising candidate model for further study.