Double White Dwarf Mergers
What happens when two white dwarfs merge and don't blow up? The fate of the merged star depends on its structure which itself is dependent on the turbulent mixing of the two stars as they merge.
The simulation pictured here contains two roughly equal-mass white dwarfs. The calculation carried out with SNSPH (Fryer et al. 2007) and visualized with SPLASH (Price 2007) for Staff et al. in prep. Plotted here is a horizontal slice through the orbital plane, though the simulation was carried out in 3D. About 20 million particles were used. Density is plotted above and specific internal energy (related to temperature) is plotted in the lower panel. Both quantities appear in code units. |
Quasar Formation
Rendering of emissivity of a young galaxy powered by an infant supermassive black hole. The cosmological calculation was carried out in Enzo and post-processed with my code AURORA.
The COSMOS survey recently detected a young proto-galaxy, CR7, which is composed almost entirely of only hydrogen and helium. Is CR7 powered by the first detected prestine stellar population, or is CR7 something else, an infant supermassive black hole? CR7 is a brilliant emitter of Lyman-alpha which could be powered by massive black hole accretion. In Smidt, Wiggins and Johnson (2016), we combine state-of-the-art cosmological calculations of a young CR7-like galaxy with Monte Carlo radiative transport to demonstrate the viability of the black hole paradigm for this exotic object. The movie below depicts the evolution of the major cosmological filament after the massive black hole forms via direct collapse. This volume rendering of density was carried out in YT and post-processed in Adobe After Effects. |