Lecture, Studium Generale

An international team of astronomers has published a map of the sky showing over 25,000 supermassive black holes. The map, to be published in the journal Astronomy & Astrophysics, is the most detailed celestial map in the field of so-called low radio frequencies. The astronomers, including Leiden astronomers,…

Meet the newest Full Professor at the Leiden Observatory: Joe Hennawi. All the way from Santa Barbara, California, Hennawi will strengthen the astronomy institute. In Leiden, he will use his recent ERC Advanced Grant to study how supermassive black holes come into existence.

Career and apply for jobs

An international team of astronomers led by Violeta Gámez Rosas (Leiden University) has observed a supermassive black hole hidden in a ring of dust. This discovery fits the idea that the so-called active centers of galaxies are much more similar than observations show, because the viewing angle from…

Since the Middle Passage is in the North Atlantic, and the North Atlantic has a relationship with the arctic, what relationship does the Arctic have with the Middle Passage? How can this relationship be used to provide a space of healing by uncovering Afro/diasporic counter narratives?

One unravels the origin of the largest black holes in the universe, the other investigates the influence of stellar wind on the atmosphere of exoplanets. Both Elena Maria Rossi and Aline Vidotto receive a Vici grant for their research into the mysteries of the universe. ‘I have no idea yet how we can…

Promotores: S.F. Portegies Zwart, E. M. Rossi

PhD defence

What is dark matter? How do supermassive black holes form? ‘Primordial’ black holes might hold the answer to these long-standing questions. Leiden and Chinese cosmologists have identified a new way in which these hypothetical objects could be produced just after the Big Bang. Publication in Physical…

The Sun and all the stars in the night sky reside in the Milky Way galaxy. In the at-rest reference frame of the Galaxy, typical stars travel with velocities of about 100-200 kilometres per second.

An Active Galactic Nucleus (AGN) is a highly luminous region at the center of a galaxy, powered by the accretion into a supermassive black hole and emitting energy from radio waves to gamma rays, often outshining the host galaxy.

Why do black holes emit thermal radiation? And how does a closed quantum system thermalize?

Schalm

The thesis deals with the study of giant radio galaxies (GRGs), which are radio galaxies of megaparsec sizes.

In this thesis, we use low-frequency and high-frequency radio observations to address the following questions regarding quasars: is the radio loud/quiet quasar dichotomy real?

Continuous optimization is never easy: the exact solution is always a luxury demand and the theory of it is not always analytical and elegant.

In this book Adam Fairclough chronicles the odyssey of black teachers in the South from emancipation in 1865 to integration one hundred years later.

This thesis aims to enhance our understanding of galaxies by testing theoretical models of galaxy formation against observations, particularly in the cases of extreme systems which have been found to have an excess of baryonic mass in their central regions, in the form of either supermassive black holes…

Optimization tasks in practice have multifaceted challenges as they are often black box, subject to multiple equality and inequality constraints and expensive to evaluate.

In White Lies and Black Markets, Fatah-Black offers a new account of the colonization of Suriname—one of the major European plantation colonies on the Guiana Coast—in the period between 1650-1800.

Lecture, Oort lecture

How is Indian foreign policy made? This special issue of the journal India Review, edited by political scientists Nicolas Blarel (Leiden University) and Avinash Paliwal (SOAS University of London) features a number of interesting case studies that bridge the gap between Foreign Policy Analysis and India’s…

An international team of astronomers has witnessed a cosmic weather event that has never been seen before.

Uncertainty and noise are frequently-encountered obstacles in real-world applications of numerical optimization. The practice of optimization that deals with uncertainties and noise is commonly referred to as robust optimization.

Donororganen zijn er nooit genoeg. De organen die wel beschikbaar zijn, moeten vliegensvlug getransplanteerd worden. De geneeskunde zet daarom volop in op het langer goedhouden van organen. Marlon de Haan (24) onderzoekt hoe je nieren buiten het lichaam in leven kunt houden.

This book is the first systematic analysis of the changes in the use of goods and services by households of Black South Africans since the early nineteenth century.

In de maanden maart, april en mei organiseerde het programma Transparantie in Informatie, van de ministeries van Economische Zaken en Klimaat (EZK) en Landbouw, Natuur en Voedselkwaliteit (LNV), gesprekken over de veranderopgave naar een Open Departement. De sessies hadden als doel om een eerlijk en…

Geheime diensten en criminelen kunnen inbreken in slimme apparaten, door slechte beveiliging. De markt lost het niet op: bedrijven willen gadgets verkopen, burgers doen ook weinig. NRC sprak hierover met Bibi van den Berg.

Through the clever use of two types of telescopes, a team of researchers has produced stunning images of clusters of galaxies. This not only produces beautiful images, but also provides more information about the enormous amounts of energy released around supermassive black holes in clusters. The astronomers,…

Finally we know for sure that there is a black hole at the centre of our own galaxy. Today, astronomers unveiled the first ever photo of Sagittarius A*, a super-massive object at the centre of the Milky Way. This picture could only be taken thanks to the cooperation of telescopes worldwide.

Een minuscuul cirkelvormig stukje DNA zorgt ervoor dat de darmbacterie Clostridioides difficile resistent raakt tegen een veelgebruikt antibioticum. Dat ontdekten wetenschappers van het Leids Universitair Medisch Centrum (LUMC) nadat artsen hen attendeerden op een patiënt met een moeilijk behandelbare…

Rossi

Scientists are asking your help to find the origin of hundreds of thousands of galaxies that have been discovered by the largest radio telescope ever built: LOFAR. Where do these mysterious objects, which extend for thousands of light-years, come from? A new citizen science project called LOFAR Radio…

When a star gets too close to a supermassive black hole, it is torn apart by strong tidal forces in a tidal disruption event (TDE).

The aim of the project is to contribute to the process of archive formation ongoing in Post-Apartheid South Africa through the inclusion of photographs that have been either unacknowledged or excised from the national canon.

The brightness peak of the ring around M87's supermassive black hole has shifted 30 degrees counterclockwise in a year. This is shown by new images released by the Event Horizon Telescope consortium.

In this thesis new methodologies are developed for the detection and systematic study of radio sources in the early universe. This allows us to gain a deeper understanding of the formation and evolution of galaxies, the activity of supermassive black holes, and the final phase transition of our universe:…

On 3 December the Europa Institute organised a debate about the figure of Black Pete. The central theme of the debate was the role which the law can play in deciding the future of Black Pete.

Lecture, Oort lecture

They are often referred to as ‘The Oscars of the Natural Sciences’: the Breakthrough Prizes in Life Sciences, Fundamental Physics and Mathematics. This year, the prize for physics went to the Event Horizon Telescope team, which took the first-ever picture of a black hole. Four Leiden astronomers were…

Stars orbit black holes while jumping up and down. This is the prediction of a theoretical model developed by Leiden physicist Satish Kumar Saravanan, based on Einstein’s theory of relativity. He defends his PhD thesis on July 7th.

Physicists understand little about quantum matter, which is a building block of future quantum computers. Theorists have now discovered that black holes with ‘dreadlocks’ harbor a similarly exotic order pattern, which makes calculations on quantum matter easier. Publication in Physical Review Letter…

All kinds of reasons have been put forward for why plants apparently fail to make maximum use of the available light. None of these reasons can explain why after two billion years of evolution they are not black, like industrial photovoltaic solar cells. Are we missing something?

Promotor: H.J.A. Rottgering, Co-Promotor: R.J. van Weeren

For the first time, astronomers have managed to take a photo of a supermassive black hole and its shadow. They used the Event Horizon Telescope (EHT), a worldwide network of eight radio telescopes that together form a virtual telescope the size of the earth. The news was presented in six press conferences…