Search Publications
Constraining the polarization content of gravitational waves with astrometry
O'Beirne, Logan; Cornish, Neil J.
Gravitational waves perturb the paths of photons, impacting both the time of flight and the arrival direction of light from stars. Pulsar timing arrays can detect gravitational waves by measuring the variations in the time of flight of radio pulses, while astrometry missions such as Gaia can detect gravitational waves from the time-varying changes…
No evidence for dust B -mode decorrelation in Planck data
Sheehy, Christopher; Slosar, Anže
Constraints on inflationary B modes using cosmic microwave background polarization data commonly rely on either template cleaning or cross-spectra between maps at different frequencies to disentangle Galactic foregrounds from the cosmological signal. Assumptions about how the foregrounds scale with frequency are therefore crucial to interpreting t…
Do cosmological data rule out f (R ) with w ≠-1 ?
Battye, Richard A.; Pace, Francesco; Bolliet, Boris
We review the equation of state (EoS) approach to dark sector perturbations and apply it to f (R ) gravity models of dark energy. We show that the EoS approach is numerically stable and use it to set observational constraints on designer models. Within the EoS approach we build an analytical understanding of the dynamics of cosmological perturbati…
Searching for signatures of dark matter-dark radiation interaction in observations of large-scale structure
Knox, Lloyd; Pan, Zhen; Kaplinghat, Manoj
In this paper, we conduct a search in the latest large-scale structure measurements for signatures of the dark matter-dark radiation interaction proposed by Buen-Abad et al. (2015). We show that prior claims of an inference of this interaction at ∼3 σ significance rely on a use of the Sunyaev-Zeldovich cluster mass function that ignores uncertaint…
Testing the equivalence principle in space after the MICROSCOPE mission
Nobili, Anna M.; Anselmi, Alberto
Tests of the weak equivalence principle (WEP) can reveal a new, composition dependent, force of nature, or disprove many models of new physics. For the first time, such a test is being successfully carried out in space by the MICROSCOPE satellite. Early results show no violation of the WEP sourced by the Earth for Pt and Ti test masses with random…
Constraints on patchy reionization from Planck CMB temperature trispectrum
Namikawa, Toshiya
We present constraints on the patchy reionization by measuring the trispectrum of the Planck 2015 cosmic microwave background (CMB) temperature anisotropies. The patchy reionization leads to anisotropies in the CMB optical depth, and the statistics of the observed CMB anisotropies is altered. We estimate the trispectrum of the CMB temperature anis…
Confronting Kähler moduli inflation with CMB data
Bhattacharya, Sukannya; Dutta, Koushik; Gangopadhyay, Mayukh Raj +1 more
In models of inflation obtained from string compactification, moduli vacuum misalignment leads to an epoch in the postinflationary history of the Universe when the energy density is dominated by cold moduli particles. This effect leads to a modification in the number of e -foldings (Npivot) between the horizon exit of the CMB modes and …
Dark energy constraints in light of Pantheon SNe Ia, BAO, cosmic chronometers and CMB polarization and lensing data
Wang, Deng
To explore whether there is new physics going beyond the standard cosmological model or not, we constrain seven cosmological models by combining the latest and largest Pantheon Type Ia supernovae sample with the data combination of baryonic acoustic oscillations, cosmic microwave background radiation, Planck lensing and cosmic chronometers. We fin…
EDGES result versus CMB and low-redshift constraints on ionization histories
Mena, Olga; Gariazzo, Stefano; Witte, Samuel +2 more
We examine the results from the Experiment to Detect the Global Epoch of Reionization Signature (EDGES), which has recently claimed the detection of a strong absorption in the 21 cm hyperfine transition line of neutral hydrogen, at redshifts demarcating the early stages of star formation. More concretely, we study the compatibility of the shape of…
Inflation with Planck data: A survey of some exotic inflationary models
Gomes, Cláudio; Bertolami, Orfeu; Rosa, João G.
We examine some inflationary models based on modifications of gravity in the light of Planck 2015 data, such as the generalized Chaplygin inspired inflation, models based in N =1 supergravity and braneworld scenarios. We also show that, conversely, potentials with a very flat plateau yield a primordial spectrum similar to that of the Starobinsky m…