Exotic Compact Objects with Reflecting Surfaces

We perform non-linear simulations of ultra-compact spacetimes with a light ring and an object with a surface that reflects scalar and/or gravitational fields.

The object's material is unknown, but replaced by reflecting boundary, whose location can be freely chosen. We investigate the dependence of the emitted waveforms on the position of the surface and compare to the non-reflecting case.

In the waveforms we are looking on features that are conjectured for some horizonless ultracompact objects, such as echoing signals and a cascade to higher multipoles