http://arxiv.org/abs/1903.06788
We use a semi-analytic model to explore the impact of radio-loud black-holes on the HI hyperfine 21 cm signal during the Cosmic Dawn. Our formalism for black-hole growth can be incorporated into existing 21 cm simulations. We find that radio emission from super-massive black hole seeds can impact the global 21 cm signal at the level of tens to hundreds of percent provided that they were radio loud and obscured by gas with column depths of $N_\text{H}\gtrsim 10^{23}$ cm$^{-2}$. We find various sets of parameters that reproduce some of the striking features of the EDGES absorption feature including its depth, timing, and side steepness while producing radio/X-ray backgrounds and source counts that are consistent with published limits. Scenarios yielding a dramatic 21 cm signature also predict large populations of $\sim \mu$Jy point sources that will be detectable in upcoming deep surveys from the Square Kilometer Array (SKA). Thus, 21 cm measurements, complemented by deep point source surveys, have the potential to constrain the radio properties of super-massive black-hole progenitors.
A. Ewall-Wice, T. Chang and T. Lazio
Tue, 19 Mar 19
45/100
Comments: 18 pages. 14 figures. Prepared for submission to MNRAS. Comments welcome
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