Search Publications
Axion cold dark matter: Status after Planck and BICEP2
Di Valentino, Eleonora; Melchiorri, Alessandro; Mena, Olga +2 more
We investigate the axion dark matter scenario (ADM), in which axions account for all of the dark matter in the Universe, in light of the most recent cosmological data. In particular, we use the Planck temperature data, complemented by WMAP E-polarization measurements, as well as the recent BICEP2 observations of B-modes. Baryon acoustic oscillatio…
Current status of modified gravity
Mena, Olga; Boubekeur, Lotfi; Ramírez, Héctor +1 more
We revisit the cosmological viability of the Hu-Sawicki modified gravity scenario. The impact of such a modification on the different cosmological observables, including gravitational waves, is carefully described. The most recent cosmological data, as well as constraints on the relationship between the clustering parameter σ8 and the c…
Model-independent fit to Planck and BICEP2 data
Mena, Olga; Barranco, Laura; Boubekeur, Lotfi
Inflation is the leading theory to describe elegantly the initial conditions that led to structure formation in our Universe. In this paper, we present a novel phenomenological fit to the Planck, WMAP polarization (WP) and the BICEP2 data sets using an alternative parametrization. Instead of starting from inflationary potentials and computing the …
Inflationary generalized Chaplygin gas and dark energy in light of the Planck and BICEP2 experiments
Kumar, Sumit; Dinda, Bikash R.; Sen, Anjan A.
In this work, we study an inflationary scenario in the presence of generalized Chaplygin gas (GCG). We show that in Einstein gravity, GCG is not a suitable candidate for inflation; but in a five-dimensional brane-world scenario, it can work as a viable inflationary model. We calculate the relevant quantities such as ns, r, and As
Probing a dark matter density spike at the Galactic Center
Silk, Joseph; Lacroix, Thomas; BÅ`hm, Céline
The dark matter halo profile in the inner Galaxy is very uncertain. Yet its radial dependence toward the Galactic Center is of crucial importance for the determination of the gamma-ray and radio fluxes originating from dark matter annihilations. Here we use synchrotron emission to probe the dark matter energy distribution in the inner Galaxy. We f…
Topological inflation from the Starobinsky model in supergravity
Yokoyama, Jun'ichi; Kamada, Kohei
We consider the ghost-free higher-order corrections to the Starobinsky model in the old-minimal supergravity, focusing on a sector among several scalar fields in the model that reproduces the scalaron potential in the original Starobinsky model. In general, higher-order corrections cannot be forbidden by symmetries, which likely violate the flatne…
Warped DGP model in warm intermediate inflation with a general dissipative coefficient in light of BICEP2 and Planck results
Videla, Nelson; Herrera, Ramón; Olivares, Marco
A warm inflationary universe scenario on a warped Dvali-Gabadadze-Porrati brane during intermediate inflation is studied. We consider a general form for the dissipative coefficient Γ (T ,ϕ )∝Tm/ϕm -1 , and also study this model in the weak and strong dissipative regimes. We analyze the evolution of the Universe in the slow-ro…
Constraining the primordial power spectrum from SNIa lensing dispersion
Ben-Dayan, Ido; Kalaydzhyan, Tigran
The (absence of detecting) lensing dispersion of supernovae type Ia (SNIa) can be used as a novel and extremely efficient probe of cosmology. In this preliminary example we analyze its consequences for the primordial power spectrum. The main setback is the knowledge of the power spectrum in the nonlinear regime, 1 Mpc-1≲k≲102…
Tachyon field inflation in light of BICEP2
Nozari, Kourosh; Rashidi, Narges
We study tachyon field inflation in the light of the Planck+WMAP+BICEP2+BAO joint data. While the minimally coupled tachyon field inflation is consistent with the Planck2013 data, it is not confirmed by the Planck+WMAP+BICEP2+BAO data set. However, a nonminimally coupled tachyon field inflation is consistent with this joint data set.
Estimating the uncorrelated dark energy evolution in the Planck era
Dai, Z. G.; Wang, F. Y.
The equation of state (EOS), w(z), is the most important parameter of dark energy. We reconstruct the evolution of this EOS in a model-independent way using the latest cosmic microwave background (CMB) data from Planck and other observations, such as type Ia supernovae, the baryonic acoustic oscillation measurements (SDSS, 6dF, BOSS, and WiggleZ),…