The eagle simulations of galaxy formation: Public release of halo and galaxy catalogues

Abstract

We present the public data release of halo and galaxy catalogues extracted from the eagle suite of cosmological hydrodynamical simulations of galaxy formation. These simulations were performed with an enhanced version of the gadget code that includes a modified hydrodynamics solver, time-step limiter and subgrid treatments of baryonic physics, such as stellar mass loss, element-by-element radiative cooling, star formation and feedback from star formation and black hole accretion. The simulation suite includes runs performed in volumes ranging from 25 to 100 comoving megaparsecs per side, with numerical resolution chosen to marginally resolve the Jeans mass of the gas at the star formation threshold. The free parameters of the subgrid models for feedback are calibrated to the redshift z = 0 galaxy stellar mass function, galaxy sizes and black hole mass -stellar mass relation. The simulations have been shown to match a wide range of observations for present-day and higher-redshift galaxies. The raw particle data have been used to link galaxies across redshifts by creating merger trees. The indexing of the tree produces a simple way to connect a galaxy at one redshift to its progenitors at higher redshift and to identify its descendants at lower redshift. In this paper we present a relational database which we are making available for general use. A large number of properties of haloes and galaxies and their merger trees are stored in the database, including stellar masses, star formation rates, metallicities, photometric measurements and mock gri images. Complex queries can be created to explore the evolution of more than 10 5 galaxies, examples of which are provided in appendix. The relatively good and broad agreement of the simulations with a wide range of observational datasets makes the database an ideal resource for the analysis of model galaxies through time, and for connecting and interpreting observational datasets.

Witnessing galaxy assembly in an extended z≈3 structure

“…Galaxies in eagle are identified as self-bound substructure inside dark matter halos, using the subfind algorithm of Springel et al (2001) and Dolag et al (2009). Next, we compute the stellar mass and SFR for each galaxy, the position and peculiar velocity of their centres of mass, as well as the mass of their parent dark matter halos (see McAlpine et al 2016). Finally, we correlate DLAs to galaxies, by combining the H i column through the eagle volume with the location of galaxies.…”

The relation between galaxy morphology and colour in the EAGLE simulation

“…Cosmological simulations of galaxy formation aim to reproduce and provide an explanation for the origin of the global properties and scaling relations revealed by galaxy surveys. The EAGLE cosmological simulation suite (Schaye et al 2015;Crain et al 2015) reproduces many properties of the observed galaxy population including the evolution of galaxy masses (Furlong et al 2015), sizes (Furlong et al 2017), star formation rates and colours (Trayford et al 2015(Trayford et al , 2016, and black hole masses and AGN luminosities (Rosas-Guevara et al 2016;Bower et al 2017;McAlpine et al 2017) with unprecedented accuracy. Trayford et al (2016) examined the origin of intrinsic colours of EAGLE galaxies, and found that while low-mass red-sequence galaxies are mostly satellites (indicative of environmental quenching), most highmass red-sequence galaxies have relatively large black hole masses (indicative of internal quenching due to AGN feedback, see Bower et al 2017).…”

The potential role of NGC 205 in generating Andromeda's vast thin corotating plane of satellite galaxies

“…There are still complexities that might be very important that are not accounted for here and really require high spatial and temporal resolution cosmological simulations such as the Caterpillar suite (Griffen et al 2016) and ELVIS suite (Exploring the Local Volume in Simulations; Garrison-Kimmel et al 2014b;McAlpine et al 2016), the latter of which crucially focuses on binary Local Group analogs.…”

“…Many recent simulations like Garrison-Kimmel et al 2014b;McAlpine et al 2016 make sure to focus only on areas of cosmological simulations with Local Group analogs when making comparisons between observations of the Milky Way or M31 and simulated halos. Several papers (for example Knebe et al 2011;Teyssier et al 2012;Fouquet et al 2012) look specifically at the exchange of satellites between M31 and the MW.…”