Radio power from direct-collapse black holes

Direct-collapse black holes (DCBHs) forming at z ∼ 20 are currently the leading candidates for theseeds of the first quasars, over 200 of which have now been found at z > 6. Recent studies suggestthat DCBHs could be detected in the near infrared by the James Webb Space Telescope, Euclid, andthe Roman Space Telescope. However, new radio telescopes with unprecedented sensitivities such asthe Square Kilometer Array (SKA) and the Next-Generation Very Large Array (ngVLA) may openanother window on the properties of DCBHs in the coming decade. Here we estimate the radio fluxfrom DCBHs at birth at z = 8 - 20 with several fundamental planes of black hole accretion. We findthat they could be detected at z ∼ 8 by the SKA-FIN all-sky survey. Furthermore, SKA and ngVLAcould discover 10⁶- 10⁷ M_⊙ BHs out to z ∼ 20, probing the formation pathways of the first quasarsin the Universe.