ETHOS – an effective theory of structure formation: predictions for the high-redshift Universe – abundance of galaxies and reionization

Lovell, Mark R; Zavala, Jesús; Vogelsberger, Mark; Shen, Xuejian; Cyr-Racine, Francis-Yan; Pfrommer, Christoph; Sigurdson, Kris; Boylan-Kolchin, Michael; Pillepich, Annalisa

Abstract

We contrast predictions for the high-redshift galaxy population and reionization history between cold dark matter (CDM) and an alternative self-interacting dark matter model based on the recently developed ETHOS framework that alleviates the small-scale CDM challenges within the Local Group. We perform the highest resolution hydrodynamical cosmological simulations (a 36 Mpc3 volume with gas cell mass of ∼105 M and minimum gas softening of ∼180 pc) within ETHOS to date – plus a CDM counterpart – to quantify the abundance of galaxies at high redshift and their impact on reionization. We find that ETHOS predicts galaxies with higher ultraviolet (UV) luminosities than their CDM counterparts and a faster build-up of the faint end of the UV luminosity function. These effects, however, make the optical depth to reionization less sensitive to the power spectrum cut-off: the ETHOS model differs from the CDM τ value by only 10 per cent and is consistent with Planck limits if the effective escape fraction of UV photons is 0.1–0.5. We conclude that current observations of high-redshift luminosity functions cannot differentiate between ETHOS and CDM models, but deep James Webb Space Telescope surveys of strongly lensed, inherently faint galaxies have the potential to test non-CDM models that offer attractive solutions to CDM’s Local Group problems.

Citation

Lovell, M. R., Zavala, J., Vogelsberger, M., Shen, X., Cyr-Racine, F.-Y., Pfrommer, C., Sigurdson, K., Boylan-Kolchin, M., & Pillepich, A. (2018). ETHOS – an effective theory of structure formation: predictions for the high-redshift Universe – abundance of galaxies and reionization. Monthly Notices of the Royal Astronomical Society, 477(3), 2886-2899. https://doi.org/10.1093/mnras/sty818

• Journal Article Type: Article
• Acceptance Date: Mar 23, 2018
• Online Publication Date: Mar 28, 2018
• Publication Date: Jul 1, 2018
• Deposit Date: May 31, 2018
• Publicly Available Date: May 31, 2018
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 477
• Issue: 3
• Pages: 2886-2899
• DOI: https://doi.org/10.1093/mnras/sty818
• Public URL: https://durham-repository.worktribe.com/output/1325277