Search Publications
A neural-network based estimator to search for primordial non-Gaussianity in Planck CMB maps
Wuensche, C. A.; Novaes, C. P.; Bernui, A. +1 more
We present an upgraded combined estimator, based on Minkowski Functionals and Neural Networks, with excellent performance in detecting primordial non-Gaussianity in simulated maps that also contain a weighted mixture of Galactic contaminations, besides real pixel's noise from Planck cosmic microwave background radiation data. We rigorously test th…
Quantum gravity and the large scale anomaly
Kamenshchik, Alexander Y.; Tronconi, Alessandro; Venturi, Giovanni
The spectrum of primordial perturbations obtained by calculating the quantum gravitational corrections to the dynamics of scalar perturbations is compared with Planck 2013 and BICEP2/Keck Array public data. The quantum gravitational effects are calculated in the context of a Wheeler-De Witt approach and have quite distinctive features. We constrai…
Revisiting a pre-inflationary radiation era and its effect on the CMB power spectrum
Goswami, Gaurav; Prasad, Jayanti; Rangarajan, Raghavan +1 more
We revisit the scenario where inflation is preceded by a radiation era by considering that the inflaton too could have been in thermal equilibrium early in the radiation era. Hence we take into account not only the effect of a pre-inflationary era on the inflaton mode functions but also that of a frozen thermal distribution of inflaton quanta. We …
Exploring the parameter space of warm-inflation models
Berera, Arjun; Bastero-Gil, Mar; Kronberg, Nico
Warm inflation includes inflaton interactions with other fields throughout the inflationary epoch instead of confining such interactions to a distinct reheating era. Previous investigations have shown that, when certain constraints on the dynamics of these interactions and the resultant radiation bath are satisfied, a low-momentum-dominated dissip…
Holographic dark energy with cosmological constant
Li, Nan; Li, Miao; Hu, Yazhou +1 more
Inspired by the multiverse scenario, we study a heterotic dark energy model in which there are two parts, the first being the cosmological constant and the second being the holographic dark energy, thus this model is named the ΛHDE model. By studying the ΛHDE model theoretically, we find that the parameters d and Ωhde are divided into a…
No evidence for the blue-tilted power spectrum of relic gravitational waves
Huang, Qing-Guo; Wang, Sai
In this paper, we constrain the tilt of the power spectrum of relic gravitational waves by combining the data from BICEP2/Keck Array and Planck (BKP) and the Laser Interferometer Gravitational-Waves Observatory (LIGO). Supposing the linearly uniform priors for both the tensor-to-scalar ratio r and the tensor tilt nt, we find nt
Limits on the fluctuating part of y-type distortion monopole from Planck and SPT results
Khatri, Rishi; Sunyaev, Rashid
We use the published Planck and SPT cluster catalogs [1,2] and recently published y-distortion maps [3] to put strong observational limits on the contribution of the fluctuating part of the y-type distortions to the y-distortion monopole. Our bounds are 5.4× 10-8 < ⟨ y⟩ < 2.2× 10-6. Our upper bound is a factor of 6.8 st…
A divergence-free parametrization for dynamical dark energy
Akarsu, Özgür; Dereli, Tekin; Vazquez, J. Alberto
We introduce a new parametrization for the dark energy, led by the same idea to the linear expansion of the equation of state in scale factor a and in redshift z, which diverges neither in the past nor future and contains the same number of degrees of freedom with the former two. We present constraints of the cosmological parameters using the most…
CMB low multipole alignments in the ΛCDM and dipolar models
Gruppuso, A.; Natoli, P.; Polastri, L.
The dipolar model [1] has attracted much interest because it may phenomenologically explain the CMB hemispherical power asymmetry found in the WMAP and Planck data. Since such a model explicitly breaks isotropy at large angular scales it is natural to wonder whether it can also explain other CMB directional anomalies. Focusing on the low ℓ alignme…
Cosmological constraints on the gravitational interactions of matter and dark matter
Bai, Yang; Salvado, Jordi; Stefanek, Ben A.
Although there is overwhelming evidence of dark matter from its gravitational interaction, we still do not know its precise gravitational interaction strength or whether it obeys the equivalence principle. Using the latest available cosmological data and working within the framework of ΛCDM, we first update the measurement of the multiplicative fa…