Explore the first galaxies through physics-based modeling, simulation, and data exploration
A 2-minute narrated scientific visualization of one of the Renaissance Simulations
A 47-minute science documentary directed by Tom Lucas. Available on Amazon Prime Video.
In Xu et al. 2013 the Rarepeak simulation is explored for the occurence of Pop III stars and their stellar remnants. The figure shows the number of active Pop III stars and remnants as a function of halo mass at z=15. As expected, the more massive the halo, the more Pop III remnants it contains. The most massive halos contain nearly 100 remnants but only a few active Pop III stars.
If one assumes a fraction of Pop III stellar remnants high mass x-ray binaries Xu et al. 2014 calculate the x-ray feedback on the intergalactic medium (IGM) in the Rarepeak simulation. On average, the x-rays heat the IGM by 100 K, but much higher in the vicinity of the Rarepeak.
Chen et al. 2014 examine statistical correlations amongst many baryonic and dark matter properties of interest in a sample of high redshift galaxies in the Rarepeak simulation. These correlations can be used to build semi-analytic models of the formation of early galaxies.
O’Shea et al. 2015 calculate the ultraviolet luminosity function for thousands of high redshift galaxies in the Rarepeak, Normal, and Void simulations, and predict a flattening at the faint magnitude end. The flattening is caused by the fact that below halo masses of around 3 x 10^8 solar masses, star formation is not continuous, reducing the average amount of UV radiation produced per galaxy at the faint end of the luminosity function.
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Ahn et al. 2015 calculate the high redshift 21 cm signal resulting from the x-ray heating of the IGM modeled by Xu et al. (2014) as discussed above. The signal depends on the x-ray source model, but in the most optimistic scenario is detectable with the future Square Kilometer Array (SKA). The figure above shows the z=19 21 cm brightness temperature power spectrum for different x-ray source energies.
Xu et al. 2016a examine the history of Pop III star formtion in the Void Renaissance Simulation, and find that it continues at a low rate to z=7.6, the lowest redshift achieved. Pop III star formation is able to continue despite the Lyman-Werner radiation from early galaxies in pristine pockets of gas.
Xu et al. 2016b calculate the x-ray background produced by Pop III stellar remnants, taking as input the extended Pop III star formation history presented in Xu et al. (2016a), and assuming a fair fraction of the stellar remnants are high mass x-ray binaries. It is found that Pop III stars can make a substantial contribution to the x-ray background.
Xu et al. 2016c present a detailed analysis of the galaxy properties and ionizing escape fraction from the combined Renaissance Simulations galaxy sample (over 10,000 high redshift galaxies).
Barrow et al. 2017 explore the photometric and spectroscopic properties of the galaxies in the Rarepeak Renaissance Simulation, in particular, as observed by the upcoming James Webb Space Telescope.
Barrow et al. 2018 continue their exploration of the observable properties of high redshift galaxies as predicted by the renaissance Simulations. Here they focus on the spectroscopic features produced by small clusters of Pop III stars, as well as x-ray binaries they may leave behind as remnants.
Smith et al. 2018 calculate the growth of Pop III stellar mass black holes by Bondi-Hoyle accretion using the full Renaissance Simulations data sets. They show that growth is negligible due to the low density environments the black holes find themselves in.