Momentum transfer models of interacting dark energy

Self Cite

We analyse the BOSS DR12 multipoles of the galaxy power spectrum jointly with measurements of the BAO scale for three different models of dark energy. We use recent measurements performed with a windowless estimator, and an independent and fast pipeline based on EFTofLSS modelling implemented via the FAST-PT algorithm to compute the integrals of the redshift-space loop corrections. We accelerate our analysis further by using the bacco linear power spectrum emulator instead of a Boltzmann solver. We perform two sets of analyses: one including 3σ Planck priors on As and ns , and another that is fully CMB-free, i.e., letting the primordial parameters vary freely. The first model we study is ΛCDM, within which we reproduce previous results obtained with the same estimator. We find a low value of the scalar amplitude in the CMB-free case, in agreement with many previous EFT-based full-shape analyses of the BOSS data. We then study wCDM, finding a lower value of the amplitude in the CMB-free run, coupled with a preference for phantom dark energy with w = -1.17+0.12 -0.11, again in broad agreement with previous results. Finally, we investigate the dark scattering model of interacting dark energy, which we label wACDM. In the CMB-free analysis, we find a large degeneracy between the interaction strength A and the amplitude As , hampering measurements of those parameters. On the contrary, in our run with a CMB prior, we are able to constrain the dark energy parameters to be w = -0.972+0.036 -0.029 and A = 3.9+3.2 -3.7, which show a 1σ hint of interacting dark energy. This is the first measurement of this parameter and demonstrates the ability of this model to alleviate the σ 8 tension. Our analysis can be used as a guide for the analysis of any model with scale-independent growth. Finally, we study the dependence of the results on the priors imposed on the nuisance parameters and find these priors to be informative, with their broadening generating shifts in the contours. We argue for an in depth study of this issue, which can affect current and forthcoming analyses of LSS data.

Section: Jcap01(2023)028mentioning

confidence: 99%

Cosmology with the EFTofLSS and BOSS: dark energy constraints and a note on priors

Carrilho¹,

Moretti²,

Pourtsidou³

2023

Self Cite

“…When only using Planck data or with Supernovae and/or BAO data such detection is unattainable and the model performance is similar to ΛCDM with no statistically significant difference. This feature is not exclusive of the model studied here, but it emerges as a generic feature of momentum transfer for a variety of realisations [15,17,23,71] (see also [19,20] for detailed discussion). Thus, we interpret the considered model as a proxy and our findings are expected to apply to similar scenarios where a momentum exchange of dark matter gives appreciable effects, in particular those able to alleviate the σ 8 tension.…”

Section: Discussionmentioning

confidence: 78%

“…Since there is no energy exchange, these interactions are elastic up to that order. 1 These models have been shown to exhibit some interesting virtues, including a promising scenario to alleviate the σ 8 tension [14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

A smoking gun from the power spectrum dipole for elastic interactions in the dark sector

Beltrán Jiménez,

Di Dio,

Figueruelo

2023

Models with pure momentum exchange in the dark sector have been shown to provide a promising scenario to tackle the tension in the clustering inferred from high- and low-redshift probes. A distinctive feature of these models is that only the Euler equation for the dark matter component is modified and the correction is such that the net effect can be associated to an additional friction determined by the interaction rate. In this work, we show that the strength of the interaction parameter needed to resolve the σ 8 tension could be detected from the dipole of the matter power spectrum that is expected to be measured by a SKA-like survey.

“…The effect of the SZ likelihood is worth of attention as similar results were found when considering other interactions where a momentum exchange takes place (see refs. [33,34,61]). In section 4 we will compute cosmological constraints for the interacting model under consideration using the most up-to-date data sets as well as forecasts for an Euclid-like galaxy survey.…”

Section: Jcap12(2022)010mentioning

confidence: 99%

“…Cosmological models where DE and CDM are coupled have been investigated in some works (see, for instance, [24][25][26][27][28][29][30][31]). Among all the plethora of interacting models, there is an interesting group which leave the background cosmology as in the standard model while involving a momentum transfer between two dark fluids [32][33][34][35][36][37][38][39][40][41]. The preservation of the standard model at the background level is an appealing property since we know ΛCDM provides a good fit for most data sets.…”

Section: Introductionmentioning

confidence: 99%

Momentum transfer in the dark sector and lensing convergence in upcoming galaxy surveys

Cardona¹,

Figueruelo

2022

We investigated a cosmological model that allows a momentum transfer between dark matter and dark energy. The interaction in the dark sector mainly affects the behaviour of perturbations on small scales while the background evolution matches the wCDM solution. As a result of the momentum transfer, these kinds of models help alleviating the σ 8 discrepancy in the standard model, but do not resolve the so-called H 0 tension. We confirm that this is indeed the case by computing cosmological constraints. While our analysis tends to favour σ 8 values lower than in ΛCDM, we do not find evidence for a non-vanishing momentum transfer in the dark sector. Since upcoming galaxy surveys will deliver information on scales and red-shift relevant for testing models allowing momentum transfer in the dark sector, we also carried out forecasts using different survey configurations. We assessed the relevance of neglecting lensing convergence κ when modelling the angular power spectrum of number counts fluctuations C ℓ ij(z,z'). We found that not including κ in analyses leads to biased constraints (≈ 1-5σ) of cosmological parameters even when including information from other experiments. Incorrectly modelling C ℓ ij(z,z') might lead to spurious detection of neutrino masses and exacerbate discrepancies in H 0 and σ 8.