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Stephen M. Wilkins

Professor of Astronomy and Public Understanding of Science, University of Sussex

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I am Professor of Astronomy and the Public Understanding of Science in the School of Mathematical and Physical Sciences (MPS) at the University of Sussex. I currently serve as Head of Physics and Astronomy, having previously served as Head of Astronomy.

Outside the University, I am the founder and chair of Curiosity Sussex, a Sussex-based science education charity that promotes curiosity and engagement with science across the local community. I am also a trustee of Science Projects, a non-profit organisation dedicated to bringing science to the public through interactive exhibits and hands-on experiences.

Research

My research focuses on understanding how galaxies form and evolve, with a particular emphasis on the early Universe and the first generations of galaxies. I investigate the physical processes that drive galaxy growth, including star formation, the assembly of stellar mass, and the interaction between galaxies and their environments across cosmic time.

My work combines both observational and theoretical approaches. On the observational side, I make use of data from some of the world’s leading astronomical facilities, including the Hubble Space Telescope, Spitzer Space Telescope, the Very Large Telescope (VLT), and ALMA, as well as the transformative capabilities of the James Webb Space Telescope (JWST). These observations are complemented by state-of-the-art galaxy formation simulations, allowing me to test theoretical models against the observed Universe and to explore the physical mechanisms shaping galaxies over billions of years.

By combining deep observations with numerical simulations, my research aims to build a more complete picture of galaxy evolution, from the earliest epochs after the Big Bang to the rich diversity of galaxies we observe today. You can see a list of publications (via ADS) here.

Observations

I previously worked extensively with observations from the Hubble Space Telescope, particularly following the installation of the Wide Field Camera 3 (WFC3) during Hubble’s final servicing mission in 2009. The dramatic improvement in near-infrared imaging provided by WFC3 opened a new window onto the distant Universe, enabling the discovery and characterisation of some of the earliest known galaxies.

More recently, my observational research has focused on the James Webb Space Telescope (JWST), whose unprecedented sensitivity and infrared capabilities are transforming our understanding of the first billion years of cosmic history. JWST is providing an unparalleled view of the earliest galaxies, allowing us to study their formation, growth, and physical properties in extraordinary detail. I wrote about some of the scientific opportunities offered by JWST in this article for The Conversation.

I am a member of several major international observational collaborations, including the Cosmic Evolution Early Release Science (CEERS) programme, COSMOS-Web, PRIMER, and NGDEEP, all of which have been awarded observing time on JWST. I am also a member of the COS Legacy Archive Spectroscopic SurveY (CLASSY), the Euclid Consortium, and the Galaxy and Mass Assembly (GAMA) Survey.

Through these collaborations, I work with large, multi-wavelength datasets spanning the nearby and distant Universe, combining observations from space- and ground-based facilities to address some of the most fundamental questions in galaxy formation and evolution.

Simulations

Alongside my observational work, I make extensive use of galaxy formation simulations, particularly large-scale hydrodynamical simulations that follow the coupled evolution of dark matter, gas, stars, and supermassive black holes across cosmic time. These simulations provide a powerful theoretical framework for interpreting observations and for exploring the physical processes that shape galaxies throughout the history of the Universe.

I was previously heavily involved in the MassiveBlack and BlueTides projects, led by Tiziana Di Matteo, which pioneered simulations of galaxy and black hole formation in the early Universe. In particular, BlueTides remains one of the largest cosmological hydrodynamical simulations ever performed and has provided important predictions for the populations of galaxies and quasars that are now being discovered by JWST.

I currently co-lead the First Light and Reionisation Epoch Simulations (FLARES) project. FLARES is a suite of cosmological zoom simulations based on the highly successful EAGLE model, but employing an innovative strategy that enables us to probe a much larger effective volume of the Universe than is possible with traditional high-resolution simulations. This approach allows us to study rare and extreme environments in the early Universe, providing new insights into the formation of the first galaxies and the processes that drove cosmic reionisation.

By combining simulations such as FLARES with cutting-edge observational data, my research seeks to build a coherent picture of how the first structures emerged from the aftermath of the Big Bang and evolved into the diverse galaxy population we observe today.

Synthetic observations

A major focus of my current research is the development of synthetic observations: techniques that transform the output of galaxy formation simulations into realistic mock observations that can be compared directly with astronomical data. This involves modelling the emission from stars, gas, and dust, accounting for observational effects such as instrumental resolution, noise, and survey selection functions, and producing synthetic images and spectra that mimic those obtained by modern telescopes.

To support this work, we have developed Synthesizer an open-source software tools that bridge the gap between theory and observation. These codes allow us to generate virtual Universes from simulations and analyse them in exactly the same way as observational datasets, enabling robust tests of galaxy formation models and helping to interpret the rapidly growing wealth of data from facilities such as JWST, Euclid, and ALMA.

Synthetic observations are becoming increasingly important in the era of precision astronomy. As both simulations and observations grow in scale and sophistication, realistic forward modelling provides a crucial link between the two, allowing us to quantify observational biases, make predictions for future surveys, and gain deeper insight into the physical processes that govern the formation and evolution of galaxies.

Research Culture

ACES

I am currently planning the STFC funded Advanced Cosmology and Extragalactic astronomy Summer school (ACES).

SAZERAC

During the COVID-19 pandemic I established the SAZERAC: the Summer All Zoom Epoch of Reionisation Astronomy Conference alongside Steve Finkelstein. SAZERAC was established to provide the opportunity for early career researchers to promote their work. The first SAZERAC meeting attracted almost 400 participants with a series of spin-offs (SIPS) and a second summer meeting in 2021.

Teaching

In addition to supervising a team of PhD students engaged in research I also teach several undergraduate or MSc modules (of parts of modules):

Administration

Civic and public engagement

Public engagement has been a cornerstone of my career, providing a pathway to achieving non-academic impact and fostering wider understanding of science. I have held leadership roles in public engagement at institutional, national, and international levels, and have extensive experience developing activities that connect cutting-edge research with diverse audiences.

Highlights include:

Through these activities, I aim to make astronomy accessible to as wide an audience as possible, inspire the next generation of scientists, and ensure that the excitement and benefits of scientific discovery are shared broadly across society.