Search Publications
Constraints on brane-world inflation from the CMB power spectrum: revisited
Gangopadhyay, Mayukh R.; Mathews, Grant J.
We analyze the Randal Sundrum brane-world inflation scenario in the context of the latest CMB constraints from Planck. We summarize constraints on the most popular classes of models and explore some more realistic inflaton effective potentials. The constraint on standard inflationary parameters changes in the brane-world scenario. We confirm that …
The PAU Survey: a forward modeling approach for narrow-band imaging
Tortorelli, Luca; Della Bruna, Lorenza; Herbel, Jörg +18 more
Weak gravitational lensing is a powerful probe of the dark sector, once measurement systematic errors can be controlled. In [1], a calibration method based on forward modeling, called MCCL, was proposed. This relies on fast image simulations (e.g., UFig [2,3]}) that capture the key features of galaxy populations and measurement effects. The MCCL a…
Bias of damped Lyman-α systems from their cross-correlation with CMB lensing
Font-Ribera, A.; Slosar, A.; Alonso, D. +1 more
We cross-correlate the positions of damped Lyman-α systems (DLAs) and their parent quasar catalog with a convergence map derived from the Planck cosmic microwave background (CMB) temperature data. We make consistent measurements of the lensing signal of both samples in both Fourier and configuration space. By interpreting the excess signal present…
E and B families of the Stokes parameters in the polarized synchrotron and thermal dust foregrounds
Liu, Hao; Naselsky, Pavel; Creswell, James
Better understanding of Galactic foregrounds is one of the main obstacles to detection of primordial gravitational waves through measurement of the B mode in the polarized microwave sky. We generalize the method proposed in [1] and decompose the polarization signals into the E and B families directly in the domain of the Stokes Q, U parameters as …
Stability of condensed fuzzy dark matter halos
Eby, Joshua; Leembruggen, Madelyn; Suranyi, Peter +1 more
Stability properties of gravitationally bound condensates composed of ultralight axionic Fuzzy Dark Matter (FDM) are studied. Previous work has shown that astrophysical collisions could make self-gravitating condensates structurally unstable, making them prone to collapse and decay; in the context of FDM, we reexamine the relevant timescales using…
Observational constraint on spherical inhomogeneity with CMB and local Hubble parameter
Ichiki, Kiyotomo; Tokutake, Masato; Yoo, Chul-Moon
We derive an observational constraint on a spherical inhomogeneity of the void centered at our position from the angular power spectrum of the cosmic microwave background (CMB) and local measurements of the Hubble parameter. The late time behaviour of the void is assumed to be well described by the so-called Λ-Lemaȋtre-Tolman-Bondi (ΛLTB) solution…
Reconstruction of a direction-dependent primordial power spectrum from Planck CMB data
Souradeep, Tarun; Sarkar, Subir; Mukherjee, Suvodip +2 more
We consider the possibility that the primordial curvature perturbation is direction-dependent. To first order this is parameterised by a quadrupolar modulation of the power spectrum and results in statistical anisotropy of the CMB, which can be quantified using `bipolar spherical harmonics'. We compute these for the Planck DR2-2015 SMICA map and e…
Observational status of Tachyon Natural Inflation and reheating
Nozari, Kourosh; Rashidi, Narges; Grøn, Øyvind
We study observational viability of Natural Inflation with a tachyon field as inflaton. By obtaining the main perturbation parameters in this model, we perform a numerical analysis on the parameter space of the model and in confrontation with 68% and 95% CL regions of Planck2015 data. By adopting a warped background geometry, we find some new cons…
From non-trivial geometries to power spectra and vice versa
Brooker, D. J.; Tsamis, N. C.; Woodard, R. P.
We review a recent formalism which derives the functional forms of the primordial—tensor and scalar—power spectra of scalar potential inflationary models. The formalism incorporates the case of geometries with non-constant first slow-roll parameter. Analytic expressions for the power spectra are given that explicitly display the dependence on the …
Can power spectrum observations rule out slow-roll inflation?
Lewis, Antony; Vieira, J. P. P.; Byrnes, Christian T.
The spectral index of scalar perturbations is an important observable that allows us to learn about inflationary physics. In particular, a detection of a significant deviation from a constant spectral index could enable us to rule out the simplest class of inflation models. We investigate whether future observations could rule out canonical single…