Impact of Massive Neutrinos and Dark Radiation on the High-redshift Cosmic Web. I. Lyα Forest Observables
Abstract
With upcoming high-quality data from surveys such as the Extended Baryon Oscillation Spectroscopic Survey or the Dark Energy Spectroscopic Instrument, improving the theoretical modeling and gaining a deeper understanding of the effects of neutrinos and dark radiation on structure formation at small scales are necessary, to obtain robust constraints free from systematic biases. Using a novel suite of hydrodynamical simulations that incorporate dark matter, baryons, massive neutrinos, and dark radiation, we present a detailed study of their impact on Lyα forest observables. In particular, we accurately measure the tomographic evolution of the shape and amplitude of the small-scale matter and flux power spectra and search for unique signatures along with preferred scales where a neutrino mass detection may be feasible. We then investigate the thermal state of the intergalactic medium (IGM) through the temperature-density relation. Our findings suggest that at k∼ 5 h {{Mpc}}-1 the suppression on the matter power spectrum induced by \sum {m}ν =0.1 {eV} neutrinos can reach ∼ 4 % at z∼ 3 when compared to a massless neutrino cosmology, and ∼ 10 % if a massless sterile neutrino is included; surprisingly, we also find good agreement (∼ 2 % ) with some analytic predictions. For the 1D flux power spectrum {P}{ F }1{{D}}, the highest response to free-streaming effects is achieved at k∼ 0.005 {[{km}/{{s}}]}-1 when \sum {m}ν =0.1 {eV}; this k-limit falls in the Lyα forest regime, making the small-scale {P}{ F }1{{D}} an excellent probe for detecting neutrino and dark radiation imprints. Our results indicate that the IGM at z∼ 3 provides the best sensitivity to active and sterile neutrinos.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- November 2017
- DOI:
- 10.3847/1538-4365/aa93d6
- arXiv:
- arXiv:1712.00230
- Bibcode:
- 2017ApJS..233...12R
- Keywords:
-
- astroparticle physics;
- cosmology: theory;
- large-scale structure of universe;
- methods: numerical;
- methods: statistical;
- neutrinos;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- ApJS, Volume 233, Issue 1, article id. 12, 23 pp. (2017)