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The frequency spectrum of the cosmic microwave background (CMB) is a relatively untapped source of data which can allow us to peer beyond the surface of last scattering. Small deviations away from a perfect blackbody shape will encode…

宇宙学与河外天体物理 · 物理学 2024-06-21 Bryce Cyr

Following the pioneering observations with COBE in the early 1990s, studies of the cosmic microwave background (CMB) have focused on temperature and polarization anisotropies. CMB spectral distortions - tiny departures of the CMB energy…

We calculate the bispectrum of the Cosmic Microwave Background (CMB) temperature anisotropies induced by the second-order fluctuations in the Boltzmann equation. In this paper, which is one of a series of papers on the numerical calculation…

宇宙学与河外天体物理 · 物理学 2015-05-13 Daisuke Nitta , Eiichiro Komatsu , Nicola Bartolo , Sabino Matarrese , Antonio Riotto

The energy spectrum of the cosmic microwave background (CMB) provides a powerful tool for constraining standard and non-standard physics in the primordial Universe. Previous studies mainly highlight spectral distortions (mu-, y- and r-type)…

宇宙学与河外天体物理 · 物理学 2015-11-04 Jens Chluba

Primordial magnetic fields will generate non-Gaussian signals in the cosmic microwave background (CMB) as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. We compute a new measure of…

宇宙学与河外天体物理 · 物理学 2012-06-15 Pranjal Trivedi , T. R. Seshadri , Kandaswamy Subramanian

We study temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation sourced from primordial cross-bispectra between metric perturbations and vector fields, which are generated from the inflation model where…

宇宙学与河外天体物理 · 物理学 2012-12-18 Maresuke Shiraishi , Shohei Saga , Shuichiro Yokoyama

We investigate a statistical anisotropy on the Cosmic Microwave Background (CMB) bispectrum, which can be generated from the primordial non-Gaussianity induced by quantum fluctuations of a vector field. We find new configurations in the…

宇宙学与河外天体物理 · 物理学 2011-12-03 Maresuke Shiraishi , Shuichiro Yokoyama

Extra radiation injection after neutrino decoupling in the early Universe contributes to the effective number of neutrino species that can be constrained by the cosmic microwave background (CMB). However, any effective neutrino number…

宇宙学与河外天体物理 · 物理学 2025-10-07 Shao-Ping Li , Jens Chluba

The CMB angular temperature fluctuations observed by COBE and WMAP enable us to place a lower limit on the spectral distortions of the CMB at any angular scale. These distortions are connected with the simple fact, that the superposition of…

天体物理学 · 物理学 2009-11-10 J. Chluba , R. A. Sunyaev

Cosmic microwave background (CMB) temperature anisotropies have and will continue to revolutionize our understanding of cosmology. The recent discovery of the previously predicted acoustic peaks in the power spectrum has established a…

天体物理学 · 物理学 2011-07-19 Wayne Hu , Scott Dodelson

Spectral features in the CMB energy spectrum contain a wealth of information about the physical processes in the early Universe, z < 2 x 10^6. The CMB spectral distortions are complementary to all other probes of cosmology. In fact, most of…

宇宙学与河外天体物理 · 物理学 2013-06-12 Rashid A. Sunyaev , Rishi Khatri

Non-Gaussianity in the inflationary perturbations can couple observable scales to modes of much longer wavelength (even superhorizon), leaving as a signature a large-angle modulation of the observed cosmic microwave background (CMB) power…

宇宙学与河外天体物理 · 物理学 2013-05-30 Fabian Schmidt , Lam Hui

Primordial magnetic fields lead to non-Gaussian signals in the Cosmic Microwave Background (CMB) even at the lowest order, as magnetic stresses, and the temperature anisotropy they induce, depend quadratically on the magnetic field. In…

宇宙学与河外天体物理 · 物理学 2009-09-03 T. R. Seshadri , Kandaswamy Subramanian

The presence of a dipolar statistical anisotropy in the spectrum of cosmic microwave background (CMB) fluctuations was reported by the Wilkinson Microwave Anisotropy Probe (WMAP), and has recently been confirmed in the Planck 2013 analysis…

宇宙学与河外天体物理 · 物理学 2014-04-29 Sugumi Kanno , Misao Sasaki , Takahiro Tanaka

In the context of inflationary scenarios, the observed large angle anisotropy of the Cosmic Microwave Background (CMB) temperature is believed to probe the primordial metric perturbations from inflation. Although the perturbations from…

天体物理学 · 物理学 2019-08-17 Somnath Bharadwaj , Dipak Munshi , Tarun Souradeep

Diffusion damping of the cosmic microwave background (CMB) power spectrum results from imperfect photon-baryon coupling in the pre-recombination plasma. At redshift $5 \times 10^4 < z < 2 \times 10^6$, the plasma acquires an effective…

Non-trivial spatial topology of the Universe can imprint potentially observable signatures on the cosmic microwave background (CMB). In this study, we investigate how deviations from the standard nearly-scale-free primordial power spectrum…

We introduce a new family of primordial cosmological perturbations that are not described by traditional power spectra. At the linear level, these perturbations live in the kernel of the spatial Laplacian operator, and thus we call them…

宇宙学与河外天体物理 · 物理学 2018-08-08 Niayesh Afshordi , Matthew C. Johnson

Primordial magnetic fields lead to non-Gaussian signals in the cosmic microwave background (CMB) even at the lowest order, as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. In…

宇宙学与河外天体物理 · 物理学 2011-01-17 Pranjal Trivedi , Kandaswamy Subramanian , T. R. Seshadri

Measurement of the cosmic microwave background (CMB) bispectrum, or three-point correlation function, has now become one of the principle efforts in early-Universe cosmology. Here we show that there is a odd-parity component of the CMB…

宇宙学与河外天体物理 · 物理学 2011-02-03 Marc Kamionkowski , Tarun Souradeep