Big and young supermassive black holes in the early Universe

Abstract

Blazars are Active Galactic Nuclei characterized by relativistic jets launched in the vicinity of the central engine (i.e. a supermassive black hole), that are oriented close to our line of sight. Their peculiar orientation makes them very efficient tracers of the overall jetted population, and due to their brightness they can be visible up to very high redshifts. A deep knowledge of these objects can provide fundamental clues to the models of formation and growth of the first supermassive black holes, but their search in the early Universe must be careful and follow a systematic approach. The discovery in the last $\sim 15$ years of extremely massive blazars at very high redshifts ($M_{\mathrm{BH}}>10^9{M}_{\odot },z>4$) revolutionized our perception of their earliest evolution: there seem to be different formation epochs for extremely massive black holes hosted in jetted ($z\sim 4$) and non-jetted systems ($z\sim 2.5$). This is not easy to explain, since one would expect that jetted sources accrete less efficiently. Small differences in the population are also derived from the search of such high-$z$ sources: we will go through the open questions in order to understand where the common knowledge stands and which steps must be undertaken to better understand the formation and common evolution of supermassive black holes and jets in the early Universe.

10 pages, 2 figures. Invited Review for the Special Issue "Jet Physics of Accreting Super Massive Black Holes" on Galaxies

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Cited by in corpus (10)

• Radio-loud Quasars above Redshift 4: VLBI Imaging of an Extended Sample
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• Radio Jet Proper-motion Analysis of Nine Distant Quasars above Redshift 3.5
• A compact symmetric radio source born at one-tenth the current age of the Universe
• Revealing faint compact radio jets at redshifts above 5 with very long baseline interferometry
• A small radio galaxy at z=4.026
• Superluminal Motion and Jet Parameters in the Gamma-ray-Emitting Narrow-Line Seyfert 1 Galaxy TXS 1206+549
• NVSS J151002+570243: accretion and spin of a z > 4 Fermi detected blazar
• Supermassive black holes and their surroundings: MeV signatures
• Milliarcsecond-resolution Radio-imaging Survey of Blazar Candidates at 4 < z < 5.4