The energy injected into galaxies from dying stars through supernovae plays an important role in how they evolve in a process known as feedback. However, cosmic rays generated by supernovae may be equally important in constructing a complete picture of galaxy evolution. The authors of today’s astrobite investigate this by producing hydrodynamics simulations including supernovae, cosmic rays, and magnetic fields.
Does the Sun shine in high-energy gamma rays? Apparently so, in the form of a halo surrounding itself. But certain features of this gamma-ray halo are perplexing.
Although magnetic fields exist virtually everywhere, we still do not know quite a lot about the role they play in the evolution of our Universe. On galaxy scales and larger, they can be difficult to observe, but may play a crucial role in how they evolve. Today’s astrobite discusses work done to try and understand how initially weak fields in the early Universe can affect galaxy evolution over time.
White dwarfs in a binary often merge into a variety of interesting phenomena. However, nobody has sought to understand the role that magnetic fields play during the merger. The authors simulate the merging of two white dwarfs with magnetic fields to see what happens.
Stars form via gravitational collapse of molecular cloud cores. But observations reveal that far less gas is turned into stars than you would suspect by naively calculating the star formation rate. So what can we do about this mismatch?
The galaxy is littered with white dwarfs, the burnt out remnants of stars that have run out of hydrogen fuel in their cores, but were too small to explode as supernovae. But far from being lifeless orbs, around a tenth of white dwarfs have powerful magnetic fields, a million times stronger than that of the Sun. How did these magnetic white dwarfs become such strong magnets? And just how many are there. The authors of this paper set out to answer the second of these questions, in the hope that it would shed light on the first.