The statistical properties of stars at redshift, z=5, compared with the present epoch

This is the author accepted manuscript. The final version is available on open access from the Royal Astronomical Society via the DOI in this recordData availability: Data that can be used to produce Table 2 and Figs. 8 to 15, and to calculate many of the values in Table 1 are provided as Additional Supporting Information (see below). Input and output files from the three calculations that were performed for this paper are available from the University of Exeter’s Open Research Exeter (ORE) repository (Bate 2022). This dataset includes the initial conditions and input files for the three SPH calculations, the SPH dump files that were used to create Figs. 3–7, and the output files that were used to produce Fig. 2 and Tables 1, 3, and 4. Additional Supporting Information may be found in the online version of this article: Data files for protostars. We provide text files of Tables 3 and 4 that give the properties of the protostars and multiple systems for each of the three calculations. These files contain the data necessary to construct Figs. 8 to 15, and to produce Table 2. Their f ile names are of the format Table3 Stars and Table4 Multiples z5 z5 MetalX.txt MetalX.txt where ‘X’ gives the metallicity (‘001’ for 0.01, ‘01’ for 0.1, or ‘1’). Animations. We provide animations of the evolution of the column density, and the gas, dust, and radiation temperatures for each of the three calculations (i.e. 12 animations). Sink particles are represented by white circles. These animations are provided to support the snapshots provided in Figs. 3 to 5. Their file names are of the format Bate2022 z5 MetalX Y.txt where ‘X’ gives the metallicity and ‘Y’ gives the variable (‘Density’, ‘Tgas’, or ‘Tdust’ or ‘Trad’).The dataset associated with this article is available in ORE at: https://doi.org/10.24378/exe.4324We report the statistical properties of stars and brown dwarfs obtained from three radiation hydrodynamical simulations of star cluster formation with metallicities of 1, 1/10 and 1/100 of the solar value. The star-forming clouds are subjected to cosmic microwave background radiation that is appropriate for star formation at a redshift z=5. The results from the three calculations are compared to each other, and to similar previously published calculations that had levels of background radiation appropriate for present-day (z=0) star formation. Each of the calculations treat dust and gas temperatures separately and include a thermochemical model of the diffuse interstellar medium. We find that whereas the stellar mass distribution is insensitive to the metallicity for present-day star formation, at z=5 the characteristic stellar mass increases with increasing metallicity and the mass distribution has a deficit of brown dwarfs and low-mass stars at solar metallicity compared to the Galactic initial mass function. We also find that the multiplicity of M-dwarfs decreases with increasing metallicity at z=5. These effects are a result of metal-rich gas being unable to cool to as low temperatures at z=5 compared to at z=0 due to the hotter cosmic microwave background radiation, which inhibits fragmentation at high densities.European Union FP7National Science Foundation (NSF