Search Publications
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…
Making maps of cosmological parameters
Mukherjee, Suvodip; Wandelt, Benjamin D.
We provide a fast algorithm to diagnose any directional dependence in the cosmological parameters by calculating maps of local cosmological parameter estimates and their joint errors. The technique implements a fast quadratic estimator technique based on Wiener filtering and convolution of the sky with a patch shape. It uses only three map-resolut…
Cosmological constraints on exotic injection of electromagnetic energy
Lesgourgues, Julien; Poulin, Vivian; Serpico, Pasquale D.
We compute cosmic microwave background (CMB) anisotropy constraints on exotic forms of energy injection in electromagnetic (e.m.) channels over a large range of timescales. We show that these constraints are very powerful around or just after recombination, although CMB keeps some sensitivity e.g. to decaying species with lifetimes as long as 10
The Atacama Cosmology Telescope: two-season ACTPol spectra and parameters
Hilton, Matt; Hasselfield, Matthew; Battaglia, Nicholas +80 more
We present the temperature and polarization angular power spectra measured by the Atacama Cosmology Telescope Polarimeter (ACTPol). We analyze night-time data collected during 2013-14 using two detector arrays at 149 GHz, from 548 deg2 of sky on the celestial equator. We use these spectra, and the spectra measured with the MBAC camera o…