CMB spectral distortions from black holes formed by vacuum bubbles

Understand

Vacuum bubbles may nucleate and expand during the cosmic inflation.

• When inflation ends, the bubbles run into the ambient plasma, producing strong shocks followed by underdensity waves, which propagate outwards.
• The bubbles themselves eventually form black holes with a wide distribution of masses.
• It has been recently suggested that such black holes may account for LIGO observations and may provide seeds for supermassive black holes observed at galactic centers.