Academic Journal
Constraining Dark Matter -- Dark Radiation interactions with CMB, BAO, and Lyman-$\alpha$
| Title: | Constraining Dark Matter -- Dark Radiation interactions with CMB, BAO, and Lyman-$\alpha$ |
|---|---|
| Authors: | Archidiacono, Maria, Hooper, Deanna C., Murgia, Riccardo, Bohr, Sebastian, Lesgourgues, Julien, Viel, Matteo |
| Publication Year: | 2019 |
| Collection: | ArXiv.org (Cornell University Library) |
| Subject Terms: | Astrophysics - Cosmology and Nongalactic Astrophysics |
| Description: | Several interesting Dark Matter (DM) models invoke a dark sector leading to two types of relic particles, possibly interacting with each other: non-relativistic DM, and relativistic Dark Radiation (DR). These models have interesting consequences for cosmological observables, and could in principle solve problems like the small-scale cold DM crisis, Hubble tension, and/or low $\sigma_8$ value. Their cosmological behaviour is captured by the ETHOS parametrisation, which includes a DR-DM scattering rate scaling like a power-law of the temperature, $T^n$. Scenarios with $n=0$, $2$, or $4$ can easily be realised in concrete dark sector set-ups. Here we update constraints on these three scenarios using recent CMB, BAO, and high-resolution Lyman-$\alpha$ data. We introduce a new Lyman-$\alpha$ likelihood that is applicable to a wide range of cosmological models with a suppression of the matter power spectrum on small scales. For $n=2$ and $4$, we find that Lyman-$\alpha$ data strengthen the CMB+BAO bounds on the DM-DR interaction rate by many orders of magnitude. However, models offering a possible solution to the missing satellite problem are still compatible with our new bounds. For $n=0$, high-resolution Lyman-$\alpha$ data bring no stronger constraints on the interaction rate than CMB+BAO data, except for extremely small values of the DR density. Using CMB+BAO data and a theory-motivated prior on the minimal density of DR, we find that the $n=0$ model can reduce the Hubble tension from $4.1\sigma$ to $2.7\sigma$, while simultaneously accommodating smaller values of the $\sigma_8$ and $S_8$ parameters hinted by cosmic shear data. ; Comment: 32 pages, 6 figures, 4 tables. Comments are welcome |
| Document Type: | text |
| Language: | unknown |
| Relation: | http://arxiv.org/abs/1907.01496 |
| DOI: | 10.1088/1475-7516/2019/10/055 |
| Availability: | https://doi.org/10.1088/1475-7516/2019/10/055 http://arxiv.org/abs/1907.01496 |
| Accession Number: | edsbas.D263EFE9 |
| Database: | BASE |
| Description not available. |