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Professor Paul Clark

Head of Astronomy Group

School of Physics and Astronomy

+44 29208 75107
Queen's Buildings - North Building, Room N/2.16, 5 The Parade, Newport Road, Cardiff, CF24 3AA
Available for postgraduate supervision


I am a Professor in the School of Physics and Astronomy. On this site you will details of the courses I teach, and information about my research (papers, talks, movies, etc).

The focus of my research is to understand how stars form, and what physical conditions are responsible for setting their properties. In the tabs above, you will find an overview of my work to date, as well as news of recent and upcoming papers.

Most of my work involves numerical simulations, such as shown in the image below, and involve a wide range of physics, such as self-gravity, fluid dynamics, thermodynamics, and the transport of radiation. Modelling all these physical processes is extremely computationally demanding and so we need to run the simulations at large supercomputing facilities such as DiRAC in the UK, as well as abroad, in the Juelich Supercomputing Centre and the Leibniz-Rechnungszentrum (both in Germany) and Texas Advanced Computing Center (USA). Please take a look at my research page for a more detailed overview of what I do.

If you have any questions about studying Physics/Astrophysics at Cardiff University, are interested in applying for a PhD with me, or simply want to chat about my research, please feel free to contact me!

























The Universe appears to have one goal: to turn matter into stars. This means that star formation research lies at the heart of almost all of present-day astronomy and astrophysics. We use star-forming regions to probe the expansion of the Universe and to test our models of cosmology. We use these same regions to study how galaxies form, grow, and mature. We also use it to understand how planets form: our own solar system probably formed while the Sun itself was still being assembled. It is the goal of star formation researchers, such as myself, to understand how the star formation processes occurs, that is, what regulates it, and why it happens where it does. Ultimately we wish to use our knowledge of star fomation to better understand they way the Universe evolved to have galaxies such as the Milky Way, and planets such as the Earth.

In my research I make use of numerial simulations to study how stars form out of the gas that comprises the interstellar medium. Star formation is, however, a large topic, spaning many orders of magnitude and a wide range of extreme environments. As such, it is often split-up into different categories, such as 'low-mass star formation', 'high-mass star formation', 'primordial star formation'. The first deals with forming stars like the Sun, while 'high-mass star formation' focuses on forming stars like those that make up the 'Trapesium' in the Orion Nebula Cluster. The final category looks at the stars that form out of gas in the early universe, that contains only hydrogen and helium, unlike the gas that presides today, which has been polluted with the heavier elements that arise from the lives and deaths of other stars (such as AGB winds and supernovae explosions).

Despite these different categories of star formation research, one central theme remains the same: star formation is a fight between the force of gravity, acting to bring the gas together, and forces such as thermal pressure, acting to push the gas apart. Our goal, through the numerical simulations, is to find out why the conditions for star formation arise, and how regions of observed active star formation come to have the conditions that they do.


Here you will find an overview of the modules that I am currently teaching in Cardiff, as well as a description of the type of projects I offer for BSci / MPhys placements. Please feel free to contact me if you need any more information.

Current lecture courses

PX4128 Data Analysis

I am the Module Organiser on the new Data Analysis course. The course introduces students to the mathematical techniques that scientists use (or should use!) to make sense of data sets, and draw reliable conclusions from their measurements. The course aims to cover a wide range of topics that will be useful to all physics students, whether they decide to pursue research careers or make the move to industry or finance after graduation.

At the moment, the course covers an introduction to Bayesian analysis, hypothesis testing, model fitting/selection, Monte-Carlo Markov Chains, Principal Component Analysis, as well as many more basic features of data analysis. The course comprises a two hour lecture and 1 hour PC lab session per week.    The latter is unassessed, but gives students the chance to try out the techniques we learn about in the lectures, as well as brush up on their coding skills (python), and get feedback on their assessments.

PX4231 Energy and Gas in Interstellar Space

I am also the Module Organiser for our newly revamped Year 4 course on the Interstellar Medium (ISM).  This course introduces students to the wide array of physical processes that shape the evolution of this vast reservoir of gas, and how it regulates the star formation that controls galactic evolution.  One of the key features of  the  ISM is how atomic processes are able to control evolution on scales of parsecs and up. In the course, the students will learn how this works, examing the physics behind supernovea, ionisation regions, molecular and atomic cooling / emission processes, and dust-gas interactions. The students will also learn the basics of fluid dynamics, including shocks and perturbation analysis to derive  soundwaves and fluid instabilities.      Much of the physics of the ISM is similar to that involved in predicting the weather or designing airplanes, so this course provides a first look at these phenomenon for those students wishing to follow more earthly pursuits when finishing university!

UC-HiPACC's 2013 International Summer School on AstroComputing: Star & Planet Formation

In 2013, I was a guest lecturer at a computational workshop run by the University of California's High Performance Computing Centre (HiPACC). The workshop was organsied by Prof. Mark Krumholz and brought together experts in computational modelling who have research backgrounds in Star and Planet formation. My lectures covered modelling the interstellar medium in Smoothed Particle Hydrodynamics (SPH). The lectures from the week are given here. In the side links, you should also be able to find the wonderful talks given by the other guest lecturers (Patrick Hennebelle, Tom Quinn, Jim Stone, Stella Offner, Robi Banerjee), as well as numerous lectures on science topics by additional lectures.

Links to the YouTube videos of the Lectures:

Day 1: Chemically reactive flows in SPH: a basic overview

Day 2: Building a simple ISM model

Day 3: Improving the basic ISM model -- some bells and whistles...

Day 4: The chemistry and thermodynamics of Pop III star formation

Day 5: SPH extras


I studied for both my undergrad (MSci) and PhD in Astrophysics at the University of St Andrews, in Scotland. After completing my PhD in 2005, I held a UKAFF Fellowship for 1 year before moving to Germany in 2006. I had a brief appointment at the AIP in Potsdam, before moving to Heidelberg in May 2006, to work at the Institut für Theoretische Astrophysik (ITA) - one of the 3 institutes that comprise the Zentrum für Astronomie Heidelberg (ZAH), that belongs to Heidelberg University. In 2014 I moved back to the UK, to Cardiff, where I took up a Senior Lecturer in the School of Physics and Astronomy at Cardiff University. I am now a Reader in Astrophysics.


Current supervision

Matthew Cusack

Matthew Cusack

Graduate Demonstrator

External profiles