tokens: both the expansion history, due to the scalar field, and the evolution of the density perturbation amplitudes, due to the coupling. 3 SIMULATIONS For our study, we produced simulations of the following three cosmologies: a reference CDM, an uncoupled quintessence model and a CDEdark matter model with a coupling parameter 0 . Following Elahi etal. ( 2015 ), we choose ( h , m , b , 8 )(0.67, 0.3175, 0.049, 0.83), ensuring all cosmologies have parameters consistent with z 0 CDM Planck data (Planck Collaboration XVI 2014a ; Planck Collaboration XIII 2016a ). The coupling parameter, 0 0.05, in our simulation is chosen to test the boundaries of allowed coupling (see Pettorino etal. 2012 ; Xia 2013 ) in order to maximize any observational differences that may exist between this cosmology and the standard CDM model. The linear power spectrum and growth factor f dln D ( a )/dln a are calculated using first-order Newtonian perturbation equations and the publicly available Boltzmann code cmbeasy (Doran 2005 ). We note that although these simulations have neglected star formation and feedback physics, baryons do not appear to significantly change the void population. Large underdense regions remain underdense, regardless of whether the simulation includes dark matter only, or accounts for hydrodynamic or full baryonic physics (Paillas etal. 2016 ). Initial conditions are generated by perturbing particles placed on a Cartesian grid with the first-order ZelDovich approximation using a modified version of the publicly available n-genic code. The modified code uses the growth factors calculated by cmbeasy to correctly calculate the particle displacements in the non-standard cosmologies. All the simulations are started at z 100 with the same phases in the density perturbations. Choosing the same initial phases results in underdense regions forming in the same locations in all simulations. Each underdense region in a given simulation has a corresponding underdense region in other simulations (perhaps with different properties such as density or size, depending on cosmology). This is the case despite potentially different exact profiles of density perturbations between cosmologies with different power spectra, such as CDM and CDE. We use dark-gadget , a modified version of the p-gadget -2 N -body code (for more details, see Carlesi etal. 2014a ). The key modifications are the inclusion of a separate gravity tree to account for the additional long-range forces arising from the scalar field, and an evolving dark matter N -body particle mass that models the decay of the dark matter density. The code requires the full evolution of the scalar field , the mass of the dark matter N -body particle and the expansion history. Our simulations are 500 h 1 Mpc boxes containing 2512 3 particles (dark matter and gas) giving a mass resolution of m dm ( m gas )6.9(1.3)10 10 h 1 M . 1 Though the mass resolution is poor for identifying haloes, this resolution is more than enough to
ner_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model I-Model O B-Model I-Model I-Model O O B-Model I-Model I-Model O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation O O B-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula O O O O O O O B-Model I-Model I-Model I-Model I-Model B-Citation I-Citation I-Citation I-Citation O B-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation O B-Citation I-Citation O O O O O O O O O O O O O O O O B-Model I-Model I-Model O O O O O O O O O O O O O O O O O B-Model I-Model I-Model I-Model O O O O O O B-Software B-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation O O O O O O O O O O O O O O O B-Model I-Model I-Model O O O O O O O O B-Software I-Software O O O O O O O O O O O O O O O O O O O O O O O O O O B-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model O B-Model O O B-Software O O O O O O B-Software I-Software B-Model I-Model O O O O O B-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model I-Model I-Model I-Model I-Model O O O O O O O O O O O O O O O O O O O O O O O O O B-Model I-Model I-Model I-Model I-Model O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O