New Paper: Early Magnetic Field Amplification

My graduate student, Daegene Koh, submitted his first paper to MNRAS two months ago, titled “Amplification of Magnetic Fields in a Primordial HII Region and Supernova”. Late last week, we resubmitted the paper after making revisions after a favorable referee report, and posted it on arXiv today. Here we run a suite of three simulations, focusing on the amplification of magnetic fields during the generation of the ionized region and in the aftermath of its supernova. We find that through small-scale dynamo action the magnetic field grows primarily when the supernova blastwave can cool efficiently, fragments, and becomes turbulent. On average, the fields are amplified by a factor of 100 in the remnant shell and up to a factor of 106 within the shock. These strengthened fields will propagate into the first generations of galaxies, possibly affecting the nature of their star formation.

Congratulations, DK, on your first paper!

28 Jun 2016

  • (abs, pdf) Fillingham et al., Under Pressure: Quenching Star Formation in Low-Mass Satellite Galaxies via Stripping
  • (abs, pdf) Wellons & Torrey, An improved probabilistic approach for linking progenitor and descendant galaxy populations using comoving number density
  • (abs, pdf) Madau & Fragos, Radiation Backgrounds at Cosmic Dawn: X-Rays from Compact Binaries
  • (abs, pdf) Meliani et al., Simulations of recoiling black holes: adaptive mesh refinement and radiative transfer
  • (abs, pdf) Chardin et al., Large scale opacity fluctuations in the Lyman alpha forest: evidence for QSOs dominating the ionising UV background at z ~ 5.5-6 ?

Presentation at the US Senate

On May 25th, I joined a group of people involved with the planetarium show Solar Superstorms to discuss impacts of space weather on Earth and the importance of computational science and visualization.  This event was organized by the NSF in support for a bill on space weather monitoring sponsored by Sen. Bill Peters (D-MI).  It was a totally new and pleasurable experience to speak in front of Senate staffers and interact with the Senator.  I spoke for 7 minutes on the importance of further supporting computational science and how visualization plays an essential role in the scientific process.  The event was standing room only with over 100 people in attendance, and from later feedback, it was very well received.  I hope in the future I can be involved in more events that have an impact on science policy.

Read more about the event in the Georgia Tech story.

Continue reading Presentation at the US Senate

22 Jun 2016

  • (abs, pdf) Marasco et al., The environmental dependence of HI in galaxies in the EAGLE simulations
  • (abs, pdf) van Dokkum et al., A High Stellar Velocity Dispersion and ~100 Globular Clusters for the Ultra Diffuse Galaxy Dragonfly 44
  • (abs, pdf) Magg et al., A New Statistical Model for Population III Supernova Rates: Discriminating Between $\Lambda$CDM and WDM Cosmologies