I investigate the statistical properties of the first galaxies formed in the Universe around 500 million years after the Big Bang, and how their light helped re-ionize the large amounts of hydrogen gas present in the early Universe. 

The statistical properties of these are highly sensitive to e.g. the properties of dark energy and dark matter, the behaviour of gravity in untested regimes, as well as galaxy and star formation astrophysics.

I develop and perform measurements of this and other physics, using observations. For this, I am a member of the the Euclid Consortium Primeval Universe Working Group and the Square Kilometer Array Epoch of Reionization Working Group. I also collaborate with leading theorists and observers in Europe and the United States working on the data from the Hubble Space Telescope and the coming James Webb Space Telescope. 

Example work the first direct measurement of the statistics of the matter distribution when the Universe was less than 1 billion years old (soon to appear!). 

This work has been supported by Stiftelsen Olle Engkvist Byggmästare, the US-Sweden Fulbright Commission, Helge Ax:son Johnson Foundation, and Längmanska Kulturfonden.