Join us at the Kavli Building or online. Registration is required if you plan to attend the lecture in person.

The afterglow from the Big Bang, called the "cosmic microwave background radiation," serves as the backlight in a shadow theater where galaxies are the actors. The structure of galaxies is still mysterious despite ever-improving telescope observations, because many of their components – including dark matter and diffuse gas ­– are invisible in ordinary light. But we can indirectly detect these features by observing the shadows that galaxies cast on the cosmic microwave background radiation. The shadows  provide clues to how galaxies form and evolve, and help us to work out the nature of dark matter and dark energy in the universe. I will describe the efforts led by SLAC scientists to reveal these galaxy silhouettes, using cosmic microwave background experiments and galaxy surveys of unprecedented scale.

About the Speaker:

Emmanuel Schaan is a staff scientist at SLAC National Accelerator Laboratory. As a cosmologist, he studies the origin and evolution of the universe by analyzing data from large telescopes in the U.S., Chile and space. His work focuses on the cosmic microwave background, the earliest light visible after the Big Bang, and on the large-scale distribution of galaxies. Schaan grew up in Paris, France. After studying at Ecole Normale Supérieure, he moved to Princeton, where he received his PhD. in 2017, and then worked as a Chamberlain Fellow at Lawrence Berkeley National Laboratory before joining SLAC in 2022. He loves astrophotography, tinkering, electronics and DIY projects.