This paper critically compares seven widely used risk assessment tools for violent extremism, including the VERA-2R, the ERG 22+, the SQAT, the IR46, the RRAP, the Radar, and the VAF.

In this thesis, we present new laboratory data of interstellar dust analogues.

The Faculty of Archaeology at Leiden University has a strong international reputation for its wide array of regional expertise. While our master’s specialisations consist of thematic courses, you are free to compliment this by choosing electives on specific regions.

Galaxies are often found in clusters, which contain many “red and dead” members that stopped forming stars in the distant past. Now, an international team of astronomers, led by Andra Stroe of Leiden Observatory and David Sobral of Leiden and the University of Lisbon, has discovered that these comatose…

Hot astrophysical plasma is ubiquitous in the Universe, from comets in our Solar system to the largest scale structures -- the cosmic web filaments. These hot plasmas, with the temperature of a few millions of degrees, are often observed in the X-ray wavelength range.

The Pontine Region Project (PRP) is an on-going archaeological project that aims to study the long-term history of settlement and landscape in the Pontine region

Dark matter is one of the biggest mysteries of the Universe. Its properties cannot be explained with the known laws of physics and elementary particles.

When galaxies collide, do the black holes at their centre form a supersized black hole? This is what we think happens, but it's not as simple as that, according to Simon Portegies Zwart. Zwart, computer scientist and astronomer, has been awarded a VICI grant to research this phenomenon.

Regional Federal Studies carefully reviews, selects and publishes high-quality articles dealing with various aspects of regionalism and federalism crossing substantive, thematic, geographical, theoretical, and methodological boundaries.

This collection of essays is the first to compare the emergence and development of these different types of regional identities.

Whilst government’s ability to design ‘context-specific’ regional innovation policy is generally assumed to depend on the region’s decision-making power, the aim of this study is to investigate how regional government matters. In order to open up the black box of policy design, the study develops a…

Building on the recent initiative to truly globalize the field of international relations, this book provides an innovative interrogation of regionalism.

What the Sex Lives of Bugs, Birds, and Beasts Tell Us About Evolution, Biodiversity, and Ourselves, Menno Schilthuizen reports from the front lines of evolutionary biology, on a quest to make sense of the origins, workings and evolution of our and other species’ reproductive selves.

How did Angkor interact with regional urban centers? How did the settlement system impact the society's agricultural system and regional resilience?

In 2015, Jorryt Matthee thought he discovered an extremely distant galaxy called CR7, which lacked elements heavier than helium. Three years later, he shows with measurements using the ALMA telescope that the galaxy does have carbon after all, and even in normal concentrations. The American Astronomical…

A galaxy is already incredibly large, but it can get even bigger. Astronomer Reinout van Weeren investigates clusters of galaxies, one of the largest structures in the universe. For his research into the origins and evolution of these clusters, he obtained an ERC Starting Grant of 1.5 million euros.…

An international team of astronomers, including Leiden's Maciej Bilicki, has discovered an enormous supercluster of galaxies. The supercluster had previously been overlooked because it was obscured by our own Milky Way. The researchers are publishing their findings in the Monthly Notices of the Royal…

A team of Leiden astronomers used the latest set of data from ESA’s Gaia mission to look for high-velocity stars being kicked out of the Milky Way, but were surprised to find stars instead sprinting inwards – perhaps from another galaxy.

Using the MUSE instrument on ESO’s Very Large Telescope in Chile, an international team of scientists, including many Leiden astronomers, have conducted the deepest spectroscopic survey ever. They focused on the Hubble Ultra Deep Field, measuring distances and properties of 1600 very faint galaxies…

Astronomers led by Pieter van Dokkum have discovered a galaxy that barely contains any dark matter, which actually proves that dark matter does indeed exist. The research results will be published this week in Nature.

An international team of astronomers that includes researchers from Leiden has discovered the most distant galaxy yet. The galaxy, called EGS8p7, is 13.23 billion light years away from Earth and already existed when the universe was only 550 million years old.

Dark matter represents around eighty per cent of the total mass in the Universe. Yet, we still don't really know what it's made of. Astronomer Pavel Mancera Piña is looking for answers. With a Veni grant from NWO and the most advanced telescopes, such as the James Webb Space Telescope, he will investigate…

Providing a valuable overview of regionalism throughout the entire continent, Regionalism in Modern Europe combines both geographical and thematic approaches to examine the origins and development of regional movements and identities in Europe from 1890 to the present.

Aviation safety is of global concern. Yet 43% of countries worldwide lack the expertise and administrative capacity to ensure effective safety oversight of the aviation activities for which they are responsible under international law.

Dwarf satellite galaxies in the Milky Way perform different dances than researchers initially expected. Marius Cautun from Durham University received a Marie Curie grant to unravel the mysteries of this orbital dance. October 1st 2018 he will start his research at the Leiden Observatory.

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

One of the key quests in astronomy is to study the growth and evolution of galaxies across cosmic time. Radio observations provide a powerful means of studying the formation of stars and subsequent buildup of distant galaxies, in a way that is unbiased by the presence of dust.

After almost twenty years the record for the most distant radio galaxy has been broken. A team of astronomers led by Leiden PhD candidate Aayush Saxena has discovered a radio galaxy from the time when the universe was just one billion years old. The galaxy is at a distance of 12 billion light years…

An international team of astronomers, with researchers at Leiden Observatory playing a leading role, has mapped the fuel for galaxy formation in the iconic Hubble Ultra Deep Field. The results of the research have been accepted for publication in The Astrophysical Journal.

By a stroke of luck, a team led by Dutch PhD student Martijn Oei has discovered a radio galaxy of at least 16 million lightyears long. The pair of plasma plumes is the largest structure made by a galaxy known thus far. The finding disproves some long-kept hypotheses about the growth of radio galaxie…

In pursuit of solutions to China’s inter-regional cross-border insolvency cooperation, my doctoral dissertation provides 10 original recommendations accompanied with comments, which are entitled “China’s Inter-regional Cross-border Insolvency Arrangement” (CICIA).

Promotor: Prof.dr. A.G.G.M. Tielens, Co-Promotor: J.B.R. Oonk

Our research primarily focuses on the early universe and its origins in theories that go beyond the Standard Model of particle physics.

In 2018, astronomer Jorryt Matthee won the C.J. Kok Jury Prize for the best dissertation of the Faculty of Science. He succeeded in finding a number of rare galaxies from the early Universe. One of them received the same initials as football player Cristiano Ronaldo: CR7.

Promotor: K. Kuijken, Co-Promotor: H. Hoekstra

Within the field of astronomy, understanding how galaxies grow and evolve from the Big Bang to the present day is a challenging and complex question.

My work is motivated by the necessity to extend Standard Model of Particle Physics in order to explain three observed phenomena that this great theory fails to accommodate

Promotor: K.H. Kuijken

Article by Leiden University political scientist Daniel Thomas about shifting norms for membership in international organisations.

How can Indonesia’s Ombudsman in the Regions be strengthened?

Freshwater biodiversity has been threatened by eutrophication due to excessive nutrients in the environment. Releasing the freshwater species from such pressures requires efforts from industry and manufacturers to avoid emissions to vulnerable and high-risk regions.

In ancient times, the steppe in the hinterland of Petra (Jordan) was transformed into a green oasis. This project tries to shed insights in the agricultural, water management and societal processes resulting in this transformation. This will be accomplished by practicing an interdisciplinary research…

The largest galaxies in the Universe feed off cosmic oceans, which helps them grow. This is the presumption of an international team of scientist with two Leiden astronomers, based on observations of the ‘Spiderweb’ galaxy. The researchers published their evidence in Science on 2 December 2016.

Galaxies in the early universe are shrouded in a kind of mist: a cloud of hydrogen. With galaxies in the later universe this mist has disappeared. Astronomer Jorryt Matthee has made the first images of this dissipating mist. PhD defence 19 September.

How do galaxies form? That is what astronomer Mariska Kriek will be researching in the coming years. She received an NWO Vici grant of 1.5 million euros to study galaxies in the early universe. ‘This research uses new and unprecedented observations from the James Webb Space Telescope (JWST). These allow…

Researchers have discovered the most distant Milky-Way-like galaxy yet observed. Dubbed REBELS-25, this disc galaxy seems as orderly as present-day galaxies, but we see it as it was when the Universe was only 700 million years old. This is surprising since, according to our current understanding of…

We explore the particle physics and quantum world at the time of the big bang.