Starlight contains a wealth of information, not only about the stars themselves, but also of the exoplanets that are bound to them. The infinitesimal signal of the planet can reveal many secrets, for example the constituents of its atmosphere.

Black holes are formed deep within dying massive stars and they signal a special evolution away from the canonical picture where the star explodes and leaves behind a neutron star. To probe these special evolutions and the formation pathways of black holes is a crucial link between our understanding of stellar evolution and gravitational wave astrophysics.

Since the universe was formed during the Big Bang, it has undergone a number of large-scale phase transitions.

The Epoch of Reionization is the period when the first stars and galaxies formed, some 13 billion years ago. During this period ionizing light produced in these galaxies escaped into the medium inbetween the galaxies. This resulted in a gradual ionization and heating of the entire Universe.

When neutron stars collide they create both light and gravitational waves. Researchers at Stockholm University are studying these collisions in the hope they will find the answer to fundamental questions – such as how the heaviest elements are formed, and how fast the universe is expanding.

The direct detection of gravitational waves has opened a completely new chapter in the study of gravity and the physics of the most compact objects in nature, black holes and neutron stars, especially using the electromagnetic counterparts

Planets around other stars than the Sun are collectively called “Exoplanets”. The first exoplanets were discovered in the late 1990s, and since then, the field has rapidly developed, with thousands of exoplanets known to date.

Since the universe was formed during the Big Bang, it has undergone a number of large-scale phase transitions.

The Milky Way is a puzzle made of hundreds of billions of individual pieces: a spectacular mixture of stars of all ages, some newly born and some as old as the Universe itself.

Massive stars (at least 8 times that of the sun) end their lives in spectacular explosions known as supernovae. Modern large-scale supernova surveys are finding new, rare types of cosmic explosions, expanding our view of both possible stellar deaths and supernova explosion physics.

diagnosing the element factories of the Universe

unravelling the nucleosynthetic content of supernovae and kilonovae.

The James Webb Space Telescope will open up a new vista for supernova studies, in particular for their chemistry. This project serves to develop new theoretical models for molecular processes in supernova ejecta, to be able to interpret and analyse the new incoming data.

About 14 billion years ago, the Universe began with the Big Bang. A few minutes later, hydrogen, helium, and traces of lithium were formed during the Big Bang Nucleosynthesis. However, the Universe expanded and cooled, leading to the end of this process after 20 minutes. Where, when, and how were the remaining elements of the periodic table produced?

The ZTF project uses a robotic telescope on Palomar in California to search for cosmic explosions like supernovae (exploding stars) or kilonovae (colliding neutronstars). Several groups at the Department of Astronomy and the Department of Physics use these data to understand supernova physics, cosmology or the creation of the heavy elements in the universe.