Search Publications

CDM/baryon isocurvature perturbations in a sneutrino curvaton model

Kawasaki, Masahiro; Harigaya, Keisuke; Hayakawa, Taku +1 more

Matter isocurvature perturbations are strictly constrained from cosmic microwave background observations. We study a sneutrino curvaton model where both cold dark matter (CDM)/baryon isocurvature perturbations are generated. In our model, total matter isocurvature perturbations are reduced since the CDM/baryon isocurvature perturbations compensate…

Superimposed oscillations in brane inflation

Martin, Jérôme; Ávila, Santiago; Steer, Danièle A.

In canonical scalar field inflation, the Starobinsky model (with a linear potential but discontinuous slope) is remarkable in that though slow-roll is violated, both the power-spectrum and bi-spectrum can be calculated exactly analytically. The two-point function is characterised by different power on large and small scales, and a burst of small a…

PLANCK and WMAP constraints on generalised Hubble flow inflationary trajectories

Contaldi, Carlo R.; Horner, Jonathan S.

We use the Hamilton-Jacobi formalism to constrain the space of possible single field, inflationary Hubble flow trajectories when compared to the WMAP and PLANK satellites Cosmic Microwave Background (CMB) results. This method yields posteriors on the space of Hubble Slow Roll (HSR) parameters that uniquely determine the history of the Hubble param…

The kinetic Sunyaev-Zel'dovich effect from the diffuse gas in the Local Group

Loeb, Abraham; Rubin, Douglas

Since the Local Group (LG) of galaxies moves with a bulk velocity with respect to the cosmic microwave background radiation (CMB), free electrons in its gaseous halo should imprint large-scale non-primordial temperature shifts in the CMB via the kinetic Sunyaev-Zel'dovich (kSZ) effect. By modeling the distribution of gas in the LG halo and using i…

Constraining primordial vector mode from B-mode polarization

Saga, Shohei; Shiraishi, Maresuke; Ichiki, Kiyotomo

The B-mode polarization spectrum of the Cosmic Microwave Background (CMB) may be the smoking gun of not only the primordial tensor mode but also of the primordial vector mode. If there exist nonzero vector-mode metric perturbations in the early Universe, they are known to be supported by anisotropic stress fluctuations of free-streaming particles …

BICEP's acceleration

Contaldi, Carlo R.

The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(ϕ) for the first time - if a single, sca…