Charlotte Mason is an Associate Professor at the Cosmic Dawn Center, Niels Bohr Institute, University of Copenhagen.

Congratulations on receiving a Semper Ardens: Accelerate grant from the Carlsberg Foundation!

Please tell us about your research and why it is important.

How did we get here? Around 100 million years after the Big Bang, theoretical models predict the first stars and galaxies formed in our Universe. As they burned and exploded, the stars created every atom in our world, except hydrogen and helium, they drove the Universe’s final phase transition by heating and ionizing intergalactic gas, and these early galaxies were the building blocks for galaxies like our own home, the Milky Way. But all of this is untested – until now we have not been able to see the earliest galaxies, so we do not have concrete evidence for how these first stars and galaxies formed. The newly launched James Webb Space Telescope now enables us to look back in time to observe extremely distant, early universe galaxies. My research aims to constrain when and how these first galaxies formed from the new JWST data.

What are your plans and what are the possibilities that this grant opens for you?

The grant will enable me to hire a postdoc and PhD student to join my group to work on these topics.

Where have you studied and which positions have you held before your current one?

I did my undergraduate studies at the University of Oxford in the UK and then a Ph.D. in the US at the University of California in Santa Barbara and Los Angeles. After my Ph.D., I was a NASA Hubble Fellow and CfA Fellow at the Center for Astrophysics | Harvard & Smithsonian in Boston, USA. I moved to the University of Copenhagen in 2021.

What was your motivation to pursue a career in physics and how did you choose the field you are now specializing in?

I was lucky to grow up in village without streetlights and was always fascinated by the night sky. When I was about 11 years old, I came across the word “astrophysicist” and looked it up in the dictionary and thought that sounded like an amazing job and never looked back! I really enjoyed maths and physics at school, and I decided even if I didn’t end up being an astrophysicist, getting an education in physics was still the right path for me.

Have you had role models or mentors? If so, what inspiration did you get from them?

I think many kinds of mentoring have been very important during my career, I think it’s so valuable to find people who you can turn to for advice. I was fortunate to have had a lot of very supportive teachers throughout school and university who always encouraged me to pursue my interests in physics and astronomy. In my research career, my Ph.D. supervisor, Tommaso Treu, is someone I have learnt so much from in terms of how to approach science and the importance of looking at the bigger picture.

Throughout my career I’ve also found it really helpful to talk with people just a bit more senior than me, who may have recently gone through similar experiences and challenges, but also have some perspective. For example, during my Ph.D. I remember being really stuck on a research problem and I just couldn’t see the way out. One of the senior Ph.D. students in my group really lifted me up by talking to me about a similar experience she’d had and acknowledging that research always has ups and downs.

What advice would you give to young people (in particular women and minorities) who would like to pursue a career in science?

Take advantages of opportunities – there are many internships, workshops and research experiences around the world which can open doors to unexpected and exciting places. These can give you hands-on research experience, the opportunity to figure out what you enjoy and what motivates you and enables you to build your network. For example, I did a research internship at NASA’s Jet Propulsion Lab in California when I was at university, and that experience inspired me to apply for a PhD in the US.

Don’t doubt yourself — don’t be afraid to take chances and make mistakes, that’s usually how you learn the most.

Define your own goals and expectations rather than comparing yourself to others.

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