Dark energy and matter interacting scenario to relieve H_(0) and S_(8) tensions

We consider a new cosmological model(calledΛCDM),in which the vacuum energy interacts with matter and radiation,and test this model using the current cosmological observations.Using the CMB+BAO+SN(CBS)dataset to constrain the model,we find that H_(0) and S_(8) tensions are relieved to 2.87σand 2.77σ,respectively.However,in this case,theΛCDM model is not favored by the data,compared withΛCDM.We find that when the H_(0) and S_(8) data are added to the data combination,the situation is significantly improved.In the CBS+H_(0) case,the model relieves the H_(0) tension to 0.47σ,and the model is favored overΛCDM.In the CBS+H_(0)+S_(8) case,we obtain a synthetically best situation,in which the H_(0) and S_(8) tensions are relieved to 0.72σand 2.11σ,respectively.In this case,the model is most favored by the data.Therefore,this cosmological model can greatly relieve the H_(0) tension and simultaneously effectively alleviate the S_(8) tension.

Impacts of gravitational-wave standard siren observations from Einstein Telescope and Cosmic Explorer on weighing neutrinos in interacting dark energy models

Multi-messenger gravitational wave(GW)observation for binary neutron star merger events could provide a rather useful tool to explore the evolution of the Universe.In particular,for the third-generation GW detectors,i.e.the Einstein Telescope(ET)and the Cosmic Explorer(CE),proposed to be built in Europe and the U.S.,respectively,lots of GW standard sirens with known redshifts could be obtained,which would exert great impacts on the cosmological parameter estimation.The total neutrino mass could be measured by cosmological observations,but such a measurement is model-dependent and currently only gives an upper limit.In this work,we wish to investigate whether the GW standard sirens observed by ET and CE could help improve the constraint on the neutrino mass,in particular in the interacting dark energy(IDE)models.We find that the GW standard siren observations from ET and CE can only slightly improve the constraint on the neutrino mass in the IDE models,compared to the current limit.The improvements in the IDE models are weaker than those in the standard cosmological model.Although the limit on neutrino mass can only be slightly updated,the constraints on other cosmological parameters can be significantly improved by using the GW observations.