Search Publications
Dark sectors of the Universe: A Euclid survey approach
Tutusaus, Isaac; Lamine, Brahim; Blanchard, Alain +3 more
In this paper we study the consequences of relaxing the hypothesis of the pressureless nature of the dark matter component when determining constraints on dark energy. To this aim we consider simple generalized dark matter models with constant equation of state parameter. We find that present-day low-redshift probes (type-Ia supernovae and baryoni…
Relationship between the CMB, Sunyaev-Zel'dovich cluster counts, and local Hubble parameter measurements in a simple void model
Oguri, Masamune; Ichiki, Kiyotomo; Yoo, Chul-Moon
The discrepancy between the amplitudes of matter fluctuations inferred from Sunyaev-Zel'dovich (SZ) cluster number counts and the measurement of temperature and polarization anisotropies of the cosmic microwave background (CMB) measured by the Planck satellite can be reconciled if the local universe is embedded in an underdense region as shown by …
Radiative seesaw model with degenerate Majorana dark matter
Okada, Hiroshi; Nomura, Takaaki; Orikasa, Yuta
We study a three-loop-induced neutrino mass model with exotic vectorlike isospin doublet leptons which contain a dark matter candidate. Then we explore lepton flavor violations and dark matter physics in a coannihilation system. In this paper, the nearly degenerate Majorana fermion dark matter can naturally be achieved at the two-loop level, while…
Probing a panoply of curvaton-decay scenarios using CMB data
Grin, Daniel; Smith, Tristan L.
In the curvaton scenario, primordial curvature perturbations are produced by a second field that is subdominant during inflation. Depending on how the curvaton decays [possibly producing baryon number, lepton number, or cold dark matter (CDM)], mixtures of correlated isocurvature perturbations are produced, allowing the curvaton scenario to be tes…
Gaussian regression and power spectral density estimation with missing data: The MICROSCOPE space mission as a case study
Métris, Gilles; Rodrigues, Manuel; Touboul, Pierre +3 more
We present a Gaussian regression method for time series with missing data and stationary residuals of unknown power spectral density (PSD). The missing data are efficiently estimated by their conditional expectation as in universal Kriging based on the circulant approximation of the complete data covariance. After initialization with an autoregres…
CMB all-scale blackbody distortions induced by linearizing temperature
Notari, Alessio; Quartin, Miguel
Cosmic microwave background (CMB) experiments, such as WMAP and Planck, measure intensity anisotropies and build maps using a linearized formula for relating them to the temperature blackbody fluctuations. However, this procedure also generates a signal in the maps in the form of y -type distortions which is degenerate with the thermal Sunyaev Zel…
Dealing with missing data in the MICROSCOPE space mission: An adaptation of inpainting to handle colored-noise data
Bergé, Joel; Métris, Gilles; Touboul, Pierre +2 more
The MICROSCOPE space mission, launched on April 25, 2016, aims to test the weak equivalence principle (WEP) with a 10-15 precision. Reaching this performance requires an accurate and robust data analysis method, especially since the possible WEP violation signal will be dominated by a strongly colored noise. An important complication is…
Reconstructing thawing quintessence with multiple datasets
Liddle, Andrew R.; Parkinson, David; Sahlén, Martin +1 more
In this work we model the quintessence potential in a Taylor series expansion, up to second order, around the present-day value of the scalar field. The field is evolved in a thawing regime assuming zero initial velocity. We use the latest data from the Planck satellite, baryonic acoustic oscillations observations from the Sloan Digital Sky Survey…
Averaged universe confronted with cosmological observations: A fully covariant approach
Ishak, Mustapha; Lin, Weikang; Wijenayake, Tharake
One of the outstanding problems in general relativistic cosmology is that of the averaging, that is, how the lumpy universe that we observe at small scales averages out to a smooth Friedmann-Lemaître-Robertson-Walker (FLRW) model. The root of the problem is that averaging does not commute with the Einstein equations that govern the dynamics of the…