Bitten Gullberg

Project title

SUB-millimetre SelecTed gAlaxies iN Cluster Environments (SUBSTANCE)

What is your project about?

The structure of the universe is a cosmic web of almost empty space (the field) with a few galaxies and regions where galaxies clump together in clusters. This environmental difference is believed to influence the production of stars, and hence the evolutionary path of galaxies. At cosmic noon (8-11.5bill years ago; the time when galaxies produced stars faster than any other epoch), we start to see solid evidence of galaxy clustering. Galaxies at this time appeared radically different from today’s galaxies, for example starburst galaxies. Starburst galaxies produced stars 10-100 times faster than the Milky Way, and are believed to have evolved into the most massive galaxies. However, their role in galaxy evolution models is still an open question. The key to establishing this, is to map the impact of the environment. SUBSTANCE will measure the physical difference between cluster and field starburst galaxies, in order to determine the evolutionary paths dependence on the environment.

How did you become interested in your particular field of research?

I have always had an interest for science and especially the natural sciences. My parents have always been supportive and encouraging and we have had long discussions about the universe and the origin on life. I took my high-school degree from Solrød Gymnasium, where I was lucky to have a teacher who was highly engaged in physics and astronomy. She awakened my intersted for astronomy along with a fascination of the fact that we can study the largest and most extreme objects in the universe only using light. As a bachelor and master student at University of Copenhagen, I met a lot of inspiring scientist and it was here I became familier with starburst galaxies. I found it fascinating that, although we have been studying these galaxies for now almost 30 years, there is still a lot we do not know about them. This fascination and eager to know more, is part of what drives my science.

What are the scientific challenges and perspectives in your project?

We have some challenges when we study galaxies, for example are the galaxies so far away that we cannot travel to them and measure their size or how efficient they are at forming stars. The only thing we have to work with is the light they emit, which we have become very good at analysing. Another challenge occurs because of the large distances in the universe and large sizes of objects, everything then takes place over many millions of years. This means that when we observe the events or objects in the universe, it is similar to a still-frame picture of a very long movie. To determine how galaxies evolve, we therefore have to study what the galaxies have in common and where they are different. Similar to if you took a picture of the Earth, where you could see some of the humans and without further information had to determine how young humans evolved into old humans.

What is your estimate of the impact, which your project may have to society in the long term?

When astrophysicists study phenomena and objects, we use the largest laboratory possible: the universe. My project will provide new knowledge about why some galaxies are better at turning gas into stars than others, which is something we cannot study in a laboratory. Computer simulations are the closest we get to reproducing the events in the universe, but we have to compare simulations with what we see on the sky to know if the simulation is telling us the true story. Further more, the astronomy community is very good at driving the technology evolution: in our eagerness to know more about the origin of the universe, we constantly require bigger and more sensitive telescopes. This drives a technological evolution which slowly seeps into society to everybody’s benefits. The Wireless Local Area Network (WLAN, also know as Wi-Fi) was for example invented by an astrophysicist.

Which impact do you expect the Sapere Aude programme will have on your career as a researcher?

We have been studying starburst galaxies for almost 30 years now, however, there is still much we do not know. For example, where does all the gas used for producing stars come from? And which mechanisms drive the formation of stars? To be a Sapere Aude: DFF-Starting Grant holder will give me the opportunity to shed light on these questions from a different angle: if we consider starburst galaxies, which have neighbour galaxies, how are they then different from the starburst galaxies, which does not have neighbours? I will form a team of young scientist who will study this question using observations and simulations. The Sapere Aude program will allow me to further develop my science project, define new projects and further develop my leaderskills for future projects.

Background and personal life

I grew up in Solrød, where I also went to school and high-school. After high-school I started studying physics at Copenhagen University, with a special focus on astrophysics. I moved to Munich after my master and worked as a PhD student at the European Southern Observatory (ESO). I afterwards continued my research as a postdoctoral researcher for four years at Durham University in the North East of England, and two years as a Hassleblad Fellow at Chalmers University of Technology, before I moved back home to Denmark and DTU Space on a Carlsberg Reintegration fellowship, where I am now senior researcher. My years abroad have been very enriching both scientifically and personally, but I am happy to be back in Denmark to contribute to Danish research.

City of your current residence

Køge

High school

Solrød Gymnasium