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Filtering by Tag: Smaug

"Dark-ages reionization and galaxy formation simulation XIV: Gas accretion, cooling and star formation in dwarf galaxies at high redshift" - Qin et al. (2018)

Alan Duffy

One of the challenges in exploring the early universe is that it is so far from us, as we peer billions of light years away to see it as it was all those billion of years ago. That means small faint objects, like dwarf galaxies, that we suspect do the main job of reionising the universe are nearly impossible to measure. It's therefore a challenge to constrain the DRAGONS universe; one way is to wait until little things build into bigger things that you then can see and test those. The other is to constrain the Semi-Analytic Models against the hydro simulations of Smaug. In this astounding exhaustive and thorough review of the two techniques my student Yuxiang Qin explores the connections and learns what to modify in one to mimic the other. Just being on top of one of these techniques would considered impressive in a PhD, to do both is truly exceptional. 

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"Dark-ages reionization and galaxy formation simulation IX: Economics of Reionizing Galaxies" - Duffy et al. (2017)

Alan Duffy

This is one of the most fun papers I have ever written (and not just because of the title). The picture astronomers have of the early universe is one of galaxies growing rapidly, turning vast quantities of gas rich clouds into stars in a boom-time of star formation. By using the Smaug simulations of this period I and my DRAGONS colleagues were able to explore this picture. We found that cold gas is indeed consumed rapidly, in just 300 million years irrespective of how stars explode or that gas can cool. However, theres so much material pouring into the galaxies at this time that they simply can't consume it all! A system where demand (gas turing into stars) can't raise to meet supply (of new primary material flowing in) is a recession.

Far from a booming bull-market, the early Universe was a recessionary bear-market and that's why I love this paper...


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