Joint Astrophysical Colloquium
Why it’s so much fun beyond the Eddington limit of accreting compact objects?
Ciro Pinto (INAF - IASF Palermo)
Thursday 12/06/2025 @ 11:30, Sala Antonio Sollima (IV piano Battiferro)
In the last decades the discovery of fully-grown supermassive black holes powering active galactic nuclei at very high redshifts, when the Universe was young, challenged the theories of black holes growth, requiring long periods of high accretion, most likely above the Eddington limit. These objects are difficult to study in sufficient detail, even with the most advanced observatories. However, in the nearby Universe, there are several objects that shine beyond Eddington, can be studied in great detail and used as local representative of early black holes. In the supermassive regime we have some narrow line Seyfert 1 galaxies and tidal disruption events, while a constellation of stellar-mass black holes and neutron stars are known to power ultraluminous X-ray sources (ULXs). A common denominator to all these objects is the presence of extremely fast winds winds, blowing at 10-20% of the speed of light, just as predicted by theoretical simulations of super-Eddington accretion. These winds carry a huge amount of power, likely affecting the local star formation and limiting the amount of matter that can reach the central accretor. Accretion around and beyond the Eddington limit is therefore a realm of exciting discoveries and challenges including supermassive black hole growth, quasar outflows, and ultra-luminous objects, pushing the boundaries of what we know about the universe. In this seminar I will discuss the state-of-art of super-Eddington accretion in different mass regimes, some current limitations, and highlight future missions that will decisively boost this research field.