We welcome Orsolya Eszter Kovács, a postdoctoral fellow at Masaryk University, Czechia, as our guest blogger. She spent over two years at the Smithsonian Astrophysical Observatory as a pre-doctoral fellow while working on the PhD she obtained from Eötvös Loránd University, Hungary. She is the first author of a recent paper presenting one of the most distant supermassive black holes ever seen.
In the past six months1 Chandra has unveiled two supermassive black holes remarkably close to their formation epoch, only about 500 million years after the big bang. These findings mark some of the most distant supermassive black holes observed to date.
Supermassive black holes, the largest type of black holes, lurk in the heart of most big galaxies. These cosmic behemoths play a central role in the formation and evolution of their hosting galaxies, exerting influence so significant that they can even suppress star formation.
The origin of these giant black holes is a subject of debate. Do they originate from the collapse of the earliest stellar population, known as Population III stars? Although it seems like an obvious explanation, to reach those immense masses observed in their later stages, these “light black hole seeds” need to be fed with an extreme amount of matter in a relatively brief period (through a process that astronomers call “accretion”). Yet, such a high accretion rate seems improbable as a universal solution, because there are physical limits on how quickly material can fall inwards. The outwards pressure from the intense radiation associated with high accretion can overcome the gravitational forces pulling material inwards, causing the material to be pushed away instead.
