[en] The EDELWEISS-II experiment, operated in the Frejus laboratory in a low-background environment, uses cryogenic germanium detectors to look for WIMPs. We present the results of a WIMP search carried out recently with ten so-called InterDigit detectors. This technology enables a high level of gamma radioactivity rejection within a controlled fiducial volume. A cross-section of 4.4 × 10⁻⁸ pb could be excluded for a WIMP mass of 85 GeV. We also present the status of the EDELWEISS-III project, which will operate 40 newly-designed FID detectors in an upgraded installation to improve significantly the sensitivity to low WIMP scattering cross-sections.

[en] We use the large BOSS DR9 sample of quasar spectra to constrain two cases of non-thermal dark matter models. cold-plus-warm dark matter (C+WDM) where the warm component is a thermal relic, and sterile neutrinos resonantly produced in the presence of a lepton asymmetry (RPSN). We establish constraints on the thermal relic mass m_x and its relative abundance F_wdm = Ω_wdm/Ω_dm using a suite of cosmological hydrodynamical simulations in 28 C+WDM configurations. We find that the 3 σ bounds in the m_x - F_wdm parameter space approximately follow F_wdm ∼ 0.35(keV /m_x)^-1.37 from BOSS data alone. We also establish constraints on sterile neutrino mass and mixing angle by further producing the non-linear flux power spectrum of 8 RPSN models, where the input linear power spectrum is computed directly from the particles distribution functions. We find values of lepton asymmetries for which sterile neutrinos as light as ∼ 6.5 keV (resp. 3.5 keV) are consistent with BOSS data at the 2 σ (resp. 3 σ) level. These limits tighten by close to a factor of 2 for values of lepton asymmetries departing from those yielding the coolest distribution functions. Our Lyman-α forest bounds can be additionally strengthened if we include higher-resolution data from XQ-100, HIRES and MIKE that allow us to probe smaller scales. At these scales, the measured flux power spectrum exhibits a suppression that can be due to Doppler broadening, IGM pressure smoothing or free-streaming of WDM particles. In order to distinguish between these mechanisms, thermal history at redshifts z ≥ 5 should be determined. In the current work, we show that if one extrapolates temperatures from lower redshifts via broken power laws in T₀ and γ, then our 3 σ C+WDM bounds strengthen to F_wdm ∼ 0.20(keV/m_x)^-1.37, and the lightest resonantly-produced sterile neutrinos consistent with our extended data set have masses of ∼ 7.0 keV at the 3 σ level. In particular, using dedicated hydrodynamical simulations, we show that a hypothetical 7 keV sterile neutrino produced in a lepton asymmetry of L = (n_νe - n_ν-bar_e)-absolute value /s = 8 x 10^-6 is consistent at 1.9 σ (resp. 3.1 σ) with BOSS (resp. BOSS + higher-resolution) data, for the thermal history models tested in this work. More information about the state of the IGM at redshifts 5-6 will allow one to conclude whether the small-scale suppression of the flux power spectrum is due to such sterile neutrino or to thermal effects. (authors)

[en] Nearby sources of cosmic rays up to a ZeV(=10²¹ eV) could be observed with a multimessenger approach including secondary γ-rays and neutrinos. If cosmic rays above ∼10¹⁸ eV are produced in magnetized environments such as galaxy clusters, the flux of secondary γ-rays can be enhanced by a factor ∼10 at Gev energies and by a factor of a few at TeV energies, compared to unmagnetized sources. Particularly enhanced are synchrotron and cascade photons from e⁺e^- pairs produced by protons from sources with relatively steep injection spectra ∝E^-2.6. Such sources should be visible at the same time in ultrahigh energy cosmic ray experiments and γ-ray telescopes

[en] In this paper, we describe a novel software tool named OASIS (AutOmotive Analysis and Safety EngIneering InStrument). OASIS supports automotive safety engineering with features allowing the creation of consistent and complete work products and to simplify and automate workflow steps from early analysis through system development to software development. More precisely, it provides support for (a) model creation and reuse, (b) analysis and documentation and (c) configuration and code generation. We present OASIS as a part of a tool chain supporting the application of a safety engineering workflow aligned with the automotive safety standard ISO 26262. In particular, we focus on OASIS' (1) support for property checking and model correction as well as its (2) support for fault tree generation and FMEA (Failure Modes and Effects Analysis) table generation. Finally, based on the case study of hybrid electric vehicle development, we demonstrate that (1) and (2) are able to strongly support FTA (Fault Tree Analysis) and FMEA

[en] If a significant fraction of the dark matter in the Universe is made of an ultra-light scalar field, named fuzzy dark matter (FDM) with a mass m(a) of the order of 10^-22-10^-21 eV, then its de Broglie wavelength is large enough to impact the physics of large-scale structure formation. In particular, the associated cut-off in the linear matter power spectrum modifies the structure of the intergalactic medium (IGM) at the scales probed by the Lyman-alpha forest of distant quasars. We study this effect by making use of dedicated cosmological simulations which take into account the hydrodynamics of the IGM. We explore heuristically the amplitude of quantum pressure for the FDM masses considered here and conclude that quantum effects should not modify significantly the non-linear evolution of matter density at the scales relevant to the measured Lyman-alpha flux power, and for m(a) greater than or ∼ 10^-22 eV. We derive a scaling law between m(a) and the mass of the well-studied thermal warm dark matter model that is best adapted to the Lyman-alpha forest data, and differs significantly from the one inferred by a simple linear extrapolation. By comparing FDM simulations with the Lyman-alpha flux power spectra determined from the BOSS survey, and marginalizing over relevant nuisance parameters, we exclude FDM masses in the range 10(-22) less than or ∼ m(a) < 2.3 x 10^-21 eV at 95 per cent CL. Adding higher resolution Lyman-alpha spectra extends the exclusion range up to 2.9 x 10^-21 eV. This provides a significant constraint on FDM models tailored to solve the 'small-scale problems' of Lambda CDM. (authors)

[en] Measurements of the Lyα forest based on large numbers of quasar spectra from sky surveys such as SDSS/eBOSS accurately probe the distribution of matter on small scales and thus provide important constraints on several ingredients of the cosmological model. A main summary statistic derived from those measurements is the one-dimensional power spectrum, P_1D, of the Lyα absorption. However, model predictions for P_1D rely on expensive hydrodynamical simulations of the intergalactic medium, which was the limiting factor in previous analyses. Datasets from upcoming surveys such as DESI will push observational accuracy near the 1%-level and probe even smaller scales. This observational push mandates even more accurate simulations as well as more careful exploration of parameter space. In this work we evaluate the robustness and accuracy of simulations and the statistical framework used to constrain cosmological parameters. We present a comparison between the grid-based simulation code Nyx and SPH-based code Gadget in the context of P_1D. In addition, we perform resolution and box-size convergence tests using Nyx code. We use a Gaussian process emulation scheme to reduce the number of simulations required for exploration of parameter space without sacrificing the model accuracy. We demonstrate the ability to produce unbiased parameter constraints in an end-to-end inference test using mock eBOSS- and DESI-like data, and we advocate for the usage of adaptive sampling schemes as opposed to using a fixed Latin hypercube design. (paper)

[en] We compare the propagation of iron and proton nuclei above 10¹⁹ eV in a structured Universe with source and magnetic field distributions obtained from a large-scale structure simulation and source densities ∼10^-5 Mpc^-3. All relevant cosmic ray interactions are taken into account, including photo-disintegration and propagation of secondary products. Iron injection predicts spectral shapes different from proton injection which disagree with existing data below ≅30 EeV. Injection of light nuclei or protons must therefore contribute at these energies. However, at higher energies, existing data are consistent with injection of pure iron with spectral indices between ∼2 and ∼2.4. This allows a significant recovery of the spectrum above ≅100 EeV, especially in the case of large deflections. Significant autocorrelation and anisotropy, and considerable cosmic variance are also predicted in this energy range. The mean atomic mass fluctuates considerably between different scenarios. At energies below 60 EeV, if the observed A > or approx. 35, magnetic fields must have a negligible effect on propagation. At the highest energies the observed flux will be dominated by only a few sources whose location may be determined by next generation experiments to within 10-20 deg. even if extra-galactic magnetic fields are important

[en] The Lyman-$\mathrm{\alpha <!--\; ??\; -->}$ forest 1D flux power spectrum is a powerful probe of several cosmological parameters. Assuming a $\mathrm{\Lambda <!--\; ??\; -->}$CDM cosmology including massive neutrinos, we find that the latest SDSS DR14 BOSS and eBOSS Lyman-$\mathrm{\alpha <!--\; ??\; -->}$ forest data is in very good agreement with current weak lensing constraints on $({\mathrm{\Omega <!--\; ??\; -->}}_m,{\mathrm{\sigma <!--\; ??\; -->}}_8)$ and has the same small level of tension with Planck. We did not identify a systematic effect in the data analysis that could explain this small tension, but we show that it can be reduced in extended cosmological models where the spectral index is not the same on the very different times and scales probed by CMB and Lyman-$\mathrm{\alpha <!--\; ??\; -->}$ data. A particular case is that of a $\mathrm{\Lambda <!--\; ??\; -->}$CDM model including a running of the spectral index on top of massive neutrinos. With combined Lyman-$\mathrm{\alpha <!--\; ??\; -->}$ and Planck data, we find a slight (3$\mathrm{\sigma <!--\; ??\; -->}$) preference for negative running, ${\mathrm{\alpha <!--\; ??\; -->}}_s=-<!--\; ???\; -->0.010\pm <!--\; ??\; -->0.004$ (68%CL). Neutrino mass bounds are found to be robust against different assumptions. In the $\mathrm{\Lambda <!--\; ??\; -->}$CDM model with running, we find $\sum <!--\; ???\; -->m_{\mathrm{\nu <!--\; ??\; -->}}<0.11$ eV at the 95% confidence level for combined Lyman-$\mathrm{\alpha <!--\; ??\; -->}$ and Planck (temperature and polarisation) data, or $\sum <!--\; ???\; -->m_{\mathrm{\nu <!--\; ??\; -->}}<0.09$ eV when adding CMB lensing and BAO data. We further provide strong and nearly model-independent bounds on the mass of thermal warm dark matter. For a conservative configuration consisting of SDSS data restricted to $z<4.5$ combined with XQ-100 Lyman-$\mathrm{\alpha <!--\; ??\; -->}$ data, we find $m_X><!--\; >\; -->5.3$ keV (95%CL).

[en] To understand the origin of ultra-high energy cosmic rays (UHECRs, defined to be above 10¹⁸ eV), it is required to model in a realistic way their propagation in the Universe. UHECRs can interact with low energy radio, microwave, infrared and optical photons to produce electron/positron pairs or pions. The latter decay and give rise to neutrinos and electromagnetic cascades extending down to MeV energies. In addition, deflections in cosmic magnetic fields can influence the spectrum and sky distribution of primary cosmic rays and, due to the increased propagation path length, the secondary neutrino and γ-ray fluxes. Neutrino, γ-ray, cosmic ray physics and extra-galactic magnetic fields are, therefore, strongly linked subjects and should be considered together in order to extract maximal information from existing and future data, like the one expected from the Auger Observatory. For that purpose, we have developed CRPropa, a publicly-available numerical package which takes into account interactions and deflections of primary UHECRs as well as propagation of secondary electromagnetic cascades and neutrinos. CRPropa allows to compute the observable properties of UHECRs and their secondaries in a variety of models for the sources and propagation of these particles. Here we present physical processes taken into account as well as benchmark examples; a detailed documentation of the code can be found on our web site. (authors)

[en] This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library “MaStar”). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17).