In order to explore the properties of cosmic neutrinos, i.e. sum of the neutrino mass （∑mv） and the effective number of neutrino species （Neff）, which affects the Hubble expansion rate H（z） and the power of obs...In order to explore the properties of cosmic neutrinos, i.e. sum of the neutrino mass （∑mv） and the effective number of neutrino species （Neff）, which affects the Hubble expansion rate H（z） and the power of observational Hubble parameter data （OHD） in constraining cosmological parameters under the ACDM model, we utilize OHD to constrain the properties of cosmic neutrinos and apply an accurate H（z） function with ∑ mv, and Neff. First, we simulate new OHD beyond the existing 43 OHD. According to the predictions of measurements of Ho （the current H（z） value）, baryon acoustic oscillations （BAO） peaks, Sandage-Loeb （SL） test and cosmic microwave background （CMB）, we as-sume observational accuracy up to 2% and redshift 0 〈 z ~〈 5. With simulated H（z） data obtained from the fiducial model, we constrain the parameters including ∑ mv, and Neff. When all parameters are set free, ∑mv 〈 0.196eV （95%） and Neff = 2.984 ± 0.826 （68%） are obtained, and when fixing Neff as the standard baseline 3.046, we attain ∑ mv 〈 0.240 eV （95%）. These constrained results are much tighter than the ones obtained by the current OHD, which makes the prospect of OHD in constraining cosmological parameters more promising as its accuracy and quantity grow.展开更多
基金supported by the National Key R&D Program of China(2017YFA0402600)the National Natural Science Foundation of China(Grant Nos.11573006 and 11528306)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase)
文摘In order to explore the properties of cosmic neutrinos, i.e. sum of the neutrino mass （∑mv） and the effective number of neutrino species （Neff）, which affects the Hubble expansion rate H（z） and the power of observational Hubble parameter data （OHD） in constraining cosmological parameters under the ACDM model, we utilize OHD to constrain the properties of cosmic neutrinos and apply an accurate H（z） function with ∑ mv, and Neff. First, we simulate new OHD beyond the existing 43 OHD. According to the predictions of measurements of Ho （the current H（z） value）, baryon acoustic oscillations （BAO） peaks, Sandage-Loeb （SL） test and cosmic microwave background （CMB）, we as-sume observational accuracy up to 2% and redshift 0 〈 z ~〈 5. With simulated H（z） data obtained from the fiducial model, we constrain the parameters including ∑ mv, and Neff. When all parameters are set free, ∑mv 〈 0.196eV （95%） and Neff = 2.984 ± 0.826 （68%） are obtained, and when fixing Neff as the standard baseline 3.046, we attain ∑ mv 〈 0.240 eV （95%）. These constrained results are much tighter than the ones obtained by the current OHD, which makes the prospect of OHD in constraining cosmological parameters more promising as its accuracy and quantity grow.
