Flamsteed Lecture: The Most Distant Quasars and the First Super-Massive Black Holes

At the centre of every large galaxy there is a super-massive black hole, with a mass up to a billion times that of the sun. 

These incredible objects grow by accreting material which is heated to temperatures of tens of thousands of degrees, giving off more light than the surrounding galaxy of stars - this is what we see as a quasar.  

Quasars are so luminous that they can be detected at great distances and hence seen as they were billions of years in the past, when the Universe was just ~5% of its current age (of 13.8 billion years). Unfortunately, such early quasars are also very rare, with just a few hundred dotted across the entire sky. 

This talk will describe how astronomers search for the most distant quasars, with a particular focus on recent discoveries from the Euclid space telescope, as well as examining the implications for the unanswered astrophysics question of how these first super-massive black holes formed so rapidly in the early Universe.

Meet the speaker

Daniel Mortlock grew up in Melbourne, Australia, where he did an undergraduate degree and then a PhD, both in physics, at the University of Melbourne.

 He moved to the UK to work on the Planck cosmic microwave background mission at the University of Cambridge, where he subsequently held a PPARC (now STFC) research fellowship. Daniel then moved to Imperial College London, becoming a permanent member of staff in 2011. 

In his research he develops and uses statistical methods to analyse large astronomical data-sets, working on a broad range of problems including the measurement of the Hubble constant, the origin of the highest energy cosmic rays, galaxy evolution, and the subject of this talk: the search for the most distant quasars and super-massive black holes.

Main image: M51: The Whirlpool Galaxy © Richard Konrad - ZWO Astronomy Photographer of the Year 2025 Annie Maunder.