Speaker
Dr
Sharanya Sur
(Institute for Theoretical Astrophysics (ITA), Univ. of Heidelberg)
Description
Over the course of the last decade, a great deal of progress has been made in understanding
the physical processes governing the birth of the first stars and their influence on later epochs
of structure formation. These studies have ignored the possible role of magnetic fields primarily
because the initial field strengths obtained from either cosmological processes like inflation and
phase transition or astrophysical processes like the Biermann battery or the Weibel instability
are highly uncertain. However, cosmological hydrodynamical simulations of primordial star
formation suggest that the gas within the first star-forming halos is turbulent. This has strong
implications on the subsequent evolution, in particular on the generation of magnetic fields via
the small-scale dynamo. Using high-resolution numerical simulations, we show that in the
presence of turbulence, weak seed magnetic fields are exponentially amplified by the small-scale
dynamo during the formation of the first stars. The presence of the small-scale dynamo can only
be identified in numerical simulations in which the turbulent motions in the central collapsing core
are resolved by at least 32 grid cells. We conclude that strong magnetic fields are generated
during the birth of the first stars in the universe, potentially modifying the mass distribution of
these stars and influencing the subsequent cosmic evolution.
Primary author
Dr
Sharanya Sur
(Institute for Theoretical Astrophysics (ITA), Univ. of Heidelberg)
Co-authors
Dr
Christoph Federrath
(Institute for Theoretical Astrophysics (ITA), Univ. of Heidelberg)
Dr
Dominik Schleicher
(ESO, Garching)
Prof.
Ralf Klessen
(Institute for Theoretical Astrophysics (ITA), Univ. of Heidelberg)
Dr
Robi Banerjee
(Institute for Theoretical Astrophysics (ITA), Univ. of Heidelberg)
