Cosmological 21cm line observations to test scenarios of super-Eddington accretion on to black holes being seeds of high-redshifted supermassive black holes

Understand

In this paper, we study scenarios of the super-Eddington accretion onto black holes at high redshifts $z > 10$, which are expected to be seeds to evolve to supermassive black holes until redshift $z \sim 7$.

• For an initial mass, $M_{\rm BH, ini} \lesssim 2 \times 10^{3} M_{\odot}$ of a seed BH, we definitely need the super-Eddington accretion, which can be applicable to both astrophysical and primordial origins.
• Such an accretion disk inevitably emitted high-energy photons which had heated the cosmological plasma of the inter-galactic medium continuously from high redshifts.
• In this case, the cosmic history of cosmological gas temperature is modified, by which the absorption feature of the cosmological 21 cm lines is suppressed.