Lensing as a probe of early universe: from CMB to galaxies

Abstract

The Cosmic Microwave Background (CMB) radiation lensing is a promising tool to study the physics of early universe. In this work we probe the imprints of deviations from isotropy and scale invariance of primordial curvature perturbation power spectrum on CMB lensing potential and convergence. Specifically, we consider a scale-dependent hemispherical asymmetry in primordial power spectrum. We show that the CMB lensing potential and convergence and also the crosscorrelation of the CMB lensing and late time galaxy convergence can probe the amplitude and the scale dependence of the dipole modulation. As another example, we consider a primordial power spectrum with local feature. We show that the CMB lensing and the cross-correlation of the CMB lensing and galaxy lensing can probe the amplitude and the shape of the local feature. We show that the cross correlation of CMB lensing convergence and galaxy lensing is capable to probe the effects of local features in power spectrum on smaller scales than the CMB lensing. Finally we showed that the current data can constrain the amplitude and moment dependence of dipole asymmetry.

Testing physical models for dipolar asymmetry: From temperature tokspace to lensing

“…In practice, we bin the estimator, Eqs. (47) and (48), into bins of width ∆ = 1, which means that the corrections to the data described above only need to be calculated once. This gives exactly the same result as if the estimators were computed for each set of p i from scratch; however, it allows us to dramatically speed up the exploration of the parameter space (this technique was also employed in [13] for the same reasons).…”

Polypolar spherical harmonic decomposition of galaxy correlators in redshift space: Toward testing cosmic rotational symmetry

“…There are already many phenomenological studies on e.g. galaxies [20][21][22][23][24][25][26][27], gravitational lensing [28][29][30], 21-cm fluctuations [31] and CMB spectral distortions [32,33]. These observables can yield the constraints at scales and redshifts unaccessible by the analysis of the CMB anisotropies, which most of the preceding studies focused on [21,[34][35][36][37][38][39][40][41].…”

Strongly scale-dependent CMB dipolar asymmetry from super-curvature fluctuations

“…As far as the dipole asymmetry is concerned, it has persisted from WMAP [5][6][7][8][9] until Planck 2015 [10,11], currently with a statistical significance around 3σ. Hopefully, precise analysis of CMB polarization data and future surveys of large scale structure, as well as their cross correlations, will help to tighten the bounds [56][57][58][59][60][61]. On the other hand, the supercurvature mode explanation used in this and many works relies on open inflation, which could in principle be tested by future experiments on the spatial curvature of our universe [62].…”