Properties of galaxies reproduced by a hydrodynamic simulation

Abstract

Previous simulations of the growth of cosmic structures have broadly reproduced the 'cosmic web' of galaxies that we see in the Universe, but failed to create a mixed population of elliptical and spiral galaxies, because of numerical inaccuracies and incomplete physical models. Moreover, they were unable to track the small-scale evolution of gas and stars to the present epoch within a representative portion of the Universe. Here we report a simulation that starts 12 million years after the Big Bang, and traces 13 billion years of cosmic evolution with 12 billion resolution elements in a cube of 106.5 megaparsecs a side. It yields a reasonable population of ellipticals and spirals, reproduces the observed distribution of galaxies in clusters and characteristics of hydrogen on large scales, and at the same time matches the 'metal' and hydrogen content of galaxies on small scales.

Massive close pairs measure rapid galaxy assembly in mergers at high redshift

“…In preliminary work, we conducted a simple proof-of-concept to combine our Thin lightcone geometries with the spectral synthesis code Sunrise (Jonsson 2006;Jonsson et al 2010), and we will release these initial synthetic images to the community. For example, Vogelsberger et al (2014a) used these to compare the Illustris to the HST Ultra Deep Field. Similarly, Kaviraj et al (2016) presented a lightcone image from the Horizon-AGN simulation (e.g., Dubois et al 2014).…”

“…The three Wide fields together total ∼ 410 arcmin 2 , about half the area surveyed by CANDELS-Wide (Grogin et al 2011;Koekemoer et al 2011). Each Thin lightcone is ∼ 8 arcmin 2 , a little smaller than the Hubble Space Telescope Ultra Deep Field (11 arcmin 2 Beckwith et al 2006), and we used these to create the synthetic Deep Fields for Illustris (Vogelsberger et al 2014b). For our investigation into pair statistics in this Section, we use the Wide lightcones.…”

“…We define δ with a technique based on the three-dimensional distance to the fifth nearest tracer, similar to Vogelsberger et al (2014a). First, the density field is smoothed by a three-dimensional Gaussian function with σ equal to the distance to the 5th nearest tracer galaxy with r-band absolute magnitude mr −19.5.…”

“…The recent emergence of relatively large (∼ 100 Mpc) hydrodynamical simulations with moderate resolution (∼ 1 kpc) and accuracy offers an opportunity to refine our assumptions about galaxy merger observability timescales (e.g., Dubois et al 2014;Khandai et al 2015;Schaye et al 2014;Vogelsberger et al 2014a). Their cosmological sizes allow us to convert these simulations into mock catalogs in the same way as has been done for several years using semianalytic and semi-empirical models, for example by using the lightcone technique to create mock galaxy catalogs as a function of angular coordinates and redshift (e. Bernyk et al 2016;Overzier et al 2013;TaghizadehPopp et al 2015).…”

The impact of galactic properties and environment on the quenching of central and satellite galaxies: a comparison between SDSS, Illustris and L-Galaxies

“…The formation of the stellar bulge and black hole are modelled quite independently in the Illustris simulation and hence relations between these two components may be taken as predictions rather than necessary consequences of the implementation, unlike in many semi-analytic models. Full details on the prescriptions for black hole growth in Illustris are given in Vogelsberger et al (2013Vogelsberger et al ( , 2014a. As with L-Galaxies, the radio mode AGN feedback prescription in Illustris leads to a quenching probability which is primarily a function of black hole mass, i.e.…”