How Little Red Dots Turn Blue: Evolution of Kelvin-Helmholtz Contracting Black Hole Envelopes and Observational Diagnostics
The study proposes a model where a rapidly growing black hole is surrounded by a thick gaseous envelope with concurrent star formation. This model explains the observed difference between little red dots (LRDs) and little blue dots (LBDs) as different evolutionary stages connected by the Kelvin-Helmholtz contraction of the envelope. The model predicts specific spectral signatures in UV-optical slopes that can be used to distinguish these transitional systems.