Search Publications
The evens and odds of CMB anomalies
Gruppuso, A.; Lattanzi, M.; Mandolesi, N. +3 more
The lack of power of large-angle CMB anisotropies is known to increase its statistical significance at higher Galactic latitudes, where a string-inspired pre-inflationary scale Δ can also be detected. Considering the Planck 2015 data, and relying largely on a Bayesian approach, we show that the effect is mostly driven by the even - ℓ harmonic mult…
New limits on coupled dark energy model after Planck 2015
Yang, Weiqiang; Wu, Yabo; Li, Hang +1 more
We used the Planck 2015 cosmic microwave background anisotropy, baryon acoustic oscillation, type-Ia supernovae, redshift-space distortions, and weak gravitational lensing to test the model parameter space of coupled dark energy. We assumed the constant and time-varying equation of state parameter for dark energy, and treated dark matter and dark …
An analytical approach to the CMB polarization in a spatially closed background
Niazy, Pedram; Abbassi, Amir H.
The scalar mode polarization of the cosmic microwave background is derived in a spatially closed universe from the Boltzmann equation using the line of sight integral method. The EE and TE multipole coefficients have been extracted analytically by considering some tolerable approximations such as considering the evolution of perturbation hydrodyna…
Linear and non-linear Modified Gravity forecasts with future surveys
Kunz, Martin; Pettorino, Valeria; Martinelli, Matteo +1 more
Modified Gravity theories generally affect the Poisson equation and the gravitational slip in an observable way, that can be parameterized by two generic functions (η and µ) of time and space. We bin their time dependence in redshift and present forecasts on each bin for future surveys like Euclid. We consider both Galaxy Clustering and Weak…
Primordial power spectrum features in phenomenological descriptions of inflation
Mena, Olga; Boubekeur, Lotfi; Gariazzo, Stefano +1 more
We extend an alternative, phenomenological approach to inflation by means of an equation of state and a sound speed, both of them functions of the number of e-folds and four phenomenological parameters. This approach captures a number of possible inflationary models, including those with non-canonical kinetic terms or scale-dependent non-gaussiani…
Cosmological models with running cosmological term and decaying dark matter
Szydłowski, Marek; Stachowski, Aleksander
We investigate the dynamics of the generalized ΛCDM model, which the Λ term is running with the cosmological time. On the example of the model Λ(t) =Λbare + α2/t2 we show the existence of a mechanism of the modification of the scaling law for energy density of dark matter: ρdm ∝a - 3 + λ(t). W…
Neutrino mass limits: Robust information from the power spectrum of galaxy surveys
Verde, Licia; Cuesta, Antonio J.; Niro, Viviana
We present cosmological upper limits on the sum of active neutrino masses using large-scale power spectrum data from the WiggleZ Dark Energy Survey and from the Sloan Digital Sky Survey - Data Release 7 (SDSS-DR7) sample of Luminous Red Galaxies (LRG). Combining measurements on the Cosmic Microwave Background temperature and polarisation anisotrop…
Hořava Gravity in the Effective Field Theory formalism: From cosmology to observational constraints
Frusciante, Noemi; Hu, Bin; Raveri, Marco +2 more
We consider Hořava gravity within the framework of the effective field theory (EFT) of dark energy and modified gravity. We work out a complete mapping of the theory into the EFT language for an action including all the operators which are relevant for linear perturbations with up to sixth order spatial derivatives. We then employ an updated versi…
Pre-inflationary relics in the CMB?
Gruppuso, A.; Mandolesi, N.; Natoli, P. +2 more
String Theory and Supergravity allow, in principle, to follow the transition of the inflaton from pre-inflationary fast roll to slow roll. This introduces an infrared depression in the primordial power spectrum that might have left an imprint in the CMB anisotropy, if it occurred at accessible wavelengths. We model the effect extending Λ CDM with …
Two emission mechanisms in the Fermi Bubbles: A possible signal of annihilating dark matter
Slatyer, Tracy R.; Hooper, Dan
We study the variation of the spectrum of the Fermi Bubbles with Galactic latitude. Far from the Galactic plane (|b|≳ 30°), the observed gamma-ray emission is nearly invariant with latitude, and is consistent with arising from inverse Compton scattering of the interstellar radiation field by cosmic-ray electrons with an approximately power-law spe…