Stockholm university

Research project Gravity Meets Light

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.

superluminal relativisitic jet
This is an artist's impression of two neutron stars colliding. The smashup between two dense stellar remnants unleashes the energy of 1,000 standard stellar nova explosions. In the aftermath of the collision a blowtorch jet of radiation is ejected at nearly the speed of light. Credit :Elizabeth Wheatley (STScI)

A neutron star is the ultra-dense collapsed core of an exploded star. They weigh about the same as our sun, but are a mere 20 kilometers across. Gravity at the surface of a neutron star is two hundred billion times stronger than that on Earth.

Binary neutron stars orbiting each other spiral inward by generating gravitational waves, which spread out into space. Finally, they crash into one another, combining to form a single neutron star which in many cases will soon collapse to a black hole. The collision produces copious quantities of heavy, radioactive matter, which is expelled into space, rendering the collision visible as a burst of electromagnetic radiation. A collision of this kind is called a kilonova, or macronova.

The Gravity Meets Light project is aimed at connecting diverse and complementary expertise across departments at SU, covering the entire chain of the kilonova event – from modelling the beginning of inspiral, through merger and nucleosynthesis, to light curve and spectral appearance. Finally - the project looks to determine the role and use of these exotic transients for cosmology.

Project members

Project managers

Stephan Rosswog

Professor

Department of Astronomy

Anders Jerkstrand

Senior Researcher

Department of Astronomy
me_kaw

Members

Anders Jerkstrand

Senior Researcher

Department of Astronomy
me_kaw

Jesper Sollerman

Professor

Department of Astronomy
Jesper

Ariel Marcelo Goobar

Professor

Department of Physics
Ariel Goobar