Simulated spectral evolution of black holes

Once formed, massive seeds grow and emit copious amounts of radiation by accreting the left-over halo gas; their spectrum can then provide crucial information on their evolution. By combining radiation-hydrodynamic and spectral synthesis codes, we simulate the time-evolving spectrum emerging from the host halo of a MBH seed with initial mass 10^5^M_{sun}_, assuming both standard Eddington-limited accretion, or slim accretion discs, appropriate for super-Eddington flows.

The emission occurs predominantly in the observed infrared-submm (1-1000{mu}m) and X-ray (0.1-100keV) bands. Such signal should be easily detectable by JWST around ~1{mu}m up to z~25, and by ATHENA (between 0.1 and 10keV, up to z~15). Ultra-deep X-ray surveys like the Chandra Deep Field South could have already detected these systems up to z~15.