scholarly journals Are Cosmic Isotropy Limits from Analyses of the Cosmic Microwave Background Credible?

2020 ◽  
Author(s):  
Michael J. Longo
Keyword(s):  
Angular Momentum ◽  
Cosmic Microwave Background ◽  
Parity Violation ◽  
Large Scale ◽  
Magnetic Moments ◽  
Primordial Black Holes ◽  
Spin Angular Momentum ◽  
Microwave Background ◽  
Fundamental Symmetry ◽  
The Universe

Recent analyses of cosmic microwave background (CMB) maps have been interpreted as demonstrating that the Universe was born without an initial rotation. However, these analyses are based on unrealistic models and do not contain essential ingredients such as quantum effects, the strong, weak and gravitational interactions between the components, their intrinsic spins and magnetic moments, as well as primordial black holes. If the Universe was born spinning these effects would distribute the initial spin angular momentum among its components long before the CMB forms at recombination. A primordial spin would now appear as a nonzero total angular momentum of its components along the direction of the original spin, and a primordial large-scale rotation would no longer be apparent. The existence of a special axis or direction would break a fundamental symmetry assumed in general relativity, cosmic isotropy, and a net angular momentum implies a cosmic parity violation.

The TopHat Cosmic Microwave Background Anisotropy Experiment

2005 ◽  
Vol 201 ◽  
pp. 65-70
Author(s):  
Robert F. Silverberg ◽  
Keyword(s):  
Cosmic Microwave Background ◽  
Large Scale ◽  
Background Radiation ◽  
High Sensitivity ◽  
Microwave Background ◽  
Long Duration ◽  
Cosmic Microwave Background Anisotropy ◽  
Microwave Background Radiation ◽  
The Universe ◽  
Large Scale Structure Formation

We have developed a balloon-borne experiment to measure the Cosmic Microwave Background Radiation anisotropy on angular scales from ˜50° down to ˜20′. The instrument observes at frequencies between 150 and 690 GHz and will be flown on an Antarctic circumpolar long duration flight. To greatly improve the experiment performance, the front-end of the experiment is mounted on the top of the balloon. With high sensitivity, broad sky coverage, and well-characterized systematic errors, the results of this experiment can be used to strongly constrain cosmological models and probe the early stages of large-scale structure formation in the Universe.

scholarly journals The Weird Side of the Universe: Preferred Axis

2017 ◽  
Vol 45 ◽  
pp. 1760009 ◽  
Author(s):  
Wen Zhao ◽  
Larissa Santos
Keyword(s):  
Cosmic Microwave Background ◽  
Large Scale ◽  
Directional Statistics ◽  
Temperature Anisotropy ◽  
Microwave Background ◽  
The Past ◽  
Cosmological Observations ◽  
Definition Of ◽  
The Universe

In both WMAP and Planck observations on the temperature anisotropy of cosmic microwave background (CMB) radiation a number of large-scale anomalies were discovered in the past years, including the CMB parity asymmetry in the low multipoles. By defining a directional statistics, we find that the CMB parity asymmetry is directional dependent, and the preferred axis is stable, which means that it is independent of the chosen CMB map, the definition of the statistic, or the CMB masks. Meanwhile, we find that this preferred axis strongly aligns with those of the CMB quadrupole, octopole, as well as those of other large-scale observations. In addition, all of them aligns with the CMB kinematic dipole, which hints to the non-cosmological origin of these directional anomalies in cosmological observations.

scholarly journals Detection of a Cross-correlation between Cosmic Microwave Background Lensing and Low-density Points

2021 ◽  
Vol 923 (2) ◽  
pp. 153
Author(s):  
Fuyu Dong ◽  
Pengjie Zhang ◽  
Le Zhang ◽  
Ji Yao ◽  
Zeyang Sun ◽  
...  
Keyword(s):  
Cosmic Microwave Background ◽  
Gravitational Lensing ◽  
Large Scale ◽  
Cross Correlation ◽  
Absolute Magnitude ◽  
Low Density ◽  
Microwave Background ◽  
Large Scale Structures ◽  
The Universe ◽  
Good Agreement

Abstract Low-density points (LDPs), obtained by removing high-density regions of observed galaxies, can trace the large-scale structures (LSSs) of the universe. In particular, it offers an intriguing opportunity to detect weak gravitational lensing from low-density regions. In this work, we investigate the tomographic cross-correlation between Planck cosmic microwave background (CMB) lensing maps and LDP-traced LSSs, where LDPs are constructed from the DR8 data release of the DESI legacy imaging survey, with about 106–107 galaxies. We find that, due to the large sky coverage (20,000 deg2) and large redshift depth (z ≤ 1.2), a significant detection (10σ–30σ) of the CMB lensing–LDP cross-correlation in all six redshift bins can be achieved, with a total significance of ∼53σ over ℓ ≤ 1024. Moreover, the measurements are in good agreement with a theoretical template constructed from our numerical simulation in the WMAP 9 yr ΛCDM cosmology. A scaling factor for the lensing amplitude A lens is constrained to A lens = 1 ± 0.12 for z < 0.2, A lens = 1.07 ± 0.07 for 0.2 < z < 0.4, and A lens = 1.07 ± 0.05 for 0.4 < z < 0.6, with the r-band absolute magnitude cut of −21.5 for LDP selection. A variety of tests have been performed to check the detection reliability against variations in LDP samples and galaxy magnitude cuts, masks, CMB lensing maps, multipole ℓ cuts, sky regions, and photo-z bias. We also perform a cross-correlation measurement between CMB lensing and galaxy number density, which is consistent with the CMB lensing–LDP cross-correlation. This work therefore further convincingly demonstrates that LDP is a competitive tracer of LSS.

scholarly journals WHAT IS THE SHAPE OF THE INITIAL STATE?

2013 ◽  
Vol 22 (12) ◽  
pp. 1341015 ◽  
Author(s):  
NISHANT AGARWAL ◽  
R. HOLMAN ◽  
ANDREW J. TOLLEY
Keyword(s):  
Cosmic Microwave Background ◽  
Quantum State ◽  
Momentum Space ◽  
Large Scale ◽  
Large Scale Structure ◽  
Operational Definition ◽  
Microwave Background ◽  
Initial State ◽  
Different Shapes ◽  
The Universe

We argue that a plausible operational definition for an initial state of the universe is the initial quantum state of the curvature perturbations generated during inflation. We provide a parametrization of this state and generalize the standard in–in formalism to incorporate the structures in this state into the computation of correlators of the perturbations. Measurements of these correlators using both the cosmic microwave background as well as large scale structure probe different structures in the initial state, as they give rise to bi- and tri-spectra peaked on different shapes of triangles and quadrilaterals in momentum space. In essence, the shapes implied by the correlators feed directly into information about the shape of the initial state and what physics could have preceded inflation to set this state up.

scholarly journals Tracing Primordial Magnetic Fields with 21 cm Line Observations

Galaxies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 37 ◽  
Author(s):  
Kerstin Kunze
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Cosmic Microwave Background ◽  
Large Scale ◽  
Numerical Solutions ◽  
Gaussian Random Field ◽  
Microwave Background ◽  
Matter Power Spectrum ◽  
Primordial Magnetic Fields ◽  
The Universe

Magnetic fields are observed on a large range of scales in the universe. Up until recently, the evidence always pointed to magnetic fields associated with some kind of structure, from planets to clusters of galaxies. Blazar observations have been used to posit the first evidence of truly cosmological magnetic fields or void magnetic fields. A cosmological magnetic field generated in the very early universe before recombination has implications for the cosmic microwave background (CMB), large scale structure as well as the 21 cm line signal. In particular, the Lorentz term causes a change in the linear matter power spectrum. Its implication on the 21 cm line signal was the focus of our recent simulations which will be summarised here. Modelling the cosmological magnetic field as a gaussian random field numerical solutions were found for magnetic fields with present day amplitudes of 5 nG and negative spectral indices which are within the range of observational constraints imposed by the cosmic microwave background (CMB).

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