scholarly journals Foreground biases on primordial non-Gaussianity measurements from the CMB temperature bispectrum: Implications for Planck and beyond

2018 ◽  
Vol 98 (8) ◽  
Author(s):  
J. Colin Hill
Keyword(s):  
Cmb Temperature

scholarly journals COSMIC COVARIANCE AND THE LOW QUADRUPOLE ANISOTROPY IN THE WMAP DATA

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1489-1497 ◽  
Author(s):  
LUNG-YIH CHIANG ◽  
PAVEL D. NASELSKY ◽  
PETER COLES
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
A Priori ◽  
Gaussian Random Field ◽  
Minimum Variance ◽  
Microwave Background ◽  
Data Release ◽  
Intrinsic Correlation ◽  
Wmap Data ◽  
Cmb Temperature

Low quadrupole power in the cosmic microwave background (CMB) temperature anisotropies has been a puzzle since WMAP data release. In this talk I will demonstrate that the minimum variance optimization (MVO), a methodology used by many authors including the WMAP science team to separate the CMB from foreground contamination, serves not only to extract the CMB, but to subtract the “cosmic covariance”, an intrinsic correlation between the CMB and the foregrounds. Such subtraction induces low variance in the signal via MVO, which in turn propagates into the multipoles, causing a quadrupole deficit with more than 90% CL. As we do not know the CMB and the foregrounds a priori, and their correlation is subtracted by the MVO in any case, there is therefore an unknown error in the quadrupole power even before the cosmic variance interpretation. We combine the MVO and Monte Carlo simulations, assuming CMB is a Gaussian random field, and the estimated quadrupole power falls in [308.13, 401.97] μ K 2 (at 1 − σ level).

scholarly journals Limits on decaying dark energy density models from the CMB temperature–redshift relation

2010 ◽  
Vol 43 (4) ◽  
pp. 1083-1093 ◽  
Author(s):  
Philippe Jetzer ◽  
Denis Puy ◽  
Monique Signore ◽  
Crescenzo Tortora
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Dark Energy Density ◽  
Cmb Temperature

scholarly journals CMB polarization can constrain cosmology better than CMB temperature

2014 ◽  
Vol 90 (6) ◽  
Author(s):  
Silvia Galli ◽  
Karim Benabed ◽  
François Bouchet ◽  
Jean-François Cardoso ◽  
Franz Elsner ◽  
...  
Keyword(s):  
Cmb Polarization ◽  
Cmb Temperature ◽  
Better Than

CMB temperature anisotropy

Cosmology ◽  
2017 ◽  
pp. 279-308
Author(s):  
Nicola Vittorio
Keyword(s):  
Temperature Anisotropy ◽  
Cmb Temperature

Maps of the CMB Temperature Anisotropy: from the Time-Ordered Data to the Maximum-Likelihood Solution

2003 ◽  
pp. 414-420
Author(s):  
Radek Stompor ◽  
Amedeo Balbi ◽  
Julian Borrill ◽  
Pedro Ferreira ◽  
Shaul Hanany ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Temperature Anisotropy ◽  
Ordered Data ◽  
Cmb Temperature

scholarly journals The Impact of CN Line Profile Measurements on the Cosmic Microwave Background Temperature

1990 ◽  
Vol 139 ◽  
pp. 390-391
Author(s):  
M. E. Kaiser ◽  
E. L. Wright
Keyword(s):  
Cosmic Microwave Background ◽  
Line Profile ◽  
Line Of Sight ◽  
High Signal ◽  
Microwave Background ◽  
A Value ◽  
Cosmic Microwave Background Temperature ◽  
Background Temperature ◽  
The Impact ◽  
Cmb Temperature

We present moderate to high signal-to-noise high-resolution (R ≈ 150,000–170,000) optical spectra toward ζ Oph. Gaussian fits to our data indicate a value of the line-width parameter b, of b = 1.4 ± 0.2 km s−1, along this line of sight. When CN is used as an indirect probe of the cosmic microwave background (CMB) temperature, the line profile is used to determine saturation corrections in the line. This affects column density calculations, which are reflected in the excitation temperature. Current measurements of the b-value along this line of sight range from 0.88 ± 0.02 km s−1 (Crane et al. 1986) to 1.3 ± 0.1 km s−1 (Hegyi, Traub, and Carleton 1972). The extreme range of these b-values yield saturation corrections to the CMB temperature that differ by 0.05 K, which is equal to the quoted precision of current measurements. Preliminary analysis of observations toward HD 29647 indicate that TCMB = 2.70 ± 0.14 K at 2.64 mm toward this line of sight.

scholarly journals Secondary CMB temperature anisotropies from magnetic reheating

2019 ◽  
Vol 490 (3) ◽  
pp. 4419-4427 ◽  
Author(s):  
Shohei Saga ◽  
Atsuhisa Ota ◽  
Hiroyuki Tashiro ◽  
Shuichiro Yokoyama
Keyword(s):  
Field Amplitude ◽  
Temperature Perturbation ◽  
Linear Parameter ◽  
Spectral Distortion ◽  
Microwave Background ◽  
Linear Coupling ◽  
Non Linear ◽  
Primordial Magnetic Fields ◽  
The Universe ◽  
Cmb Temperature

ABSTRACT Spatially fluctuating primordial magnetic fields (PMFs) inhomogeneously reheat the Universe when they dissipate deep inside the horizon before recombination. Such an energy injection turns into an additional photon temperature perturbation. We investigate secondary cosmic microwave background (CMB) temperature anisotropies originated from this mechanism, which we call inhomogeneous magnetic reheating. We find that it can bring us information about non-linear coupling between PMFs and primordial curvature perturbations parametrized by bNL, which should be important for probing the generation mechanism of PMFs. In fact, by using current CMB observations, we obtain an upper bound on the non-linear parameter as log (bNL(Bλ/nG)2) ≲ − 36.5nB − 94.0 with Bλ and nB being a magnetic field amplitude smoothed over λ = 1 Mpc scale and a spectral index of the PMF power spectrum, respectively. Our constraints are far stronger than a previous forecast based on the future CMB spectral distortion anisotropy measurements because inhomogeneous magnetic reheating covers a much wider range of scales, i.e. 1 Mpc−1 ≲ k ≲ 1015 Mpc−1.

scholarly journals Distant foreground and the Planck-derived Hubble constant

2020 ◽  
Vol 492 (4) ◽  
pp. 5052-5056 ◽  
Author(s):  
V N Yershov ◽  
A A Raikov ◽  
N Yu Lovyagin ◽  
N P M Kuin ◽  
E A Popova
Keyword(s):  
Hubble Constant ◽  
Temperature Fluctuations ◽  
Coarse Grain ◽  
Model Parameters ◽  
Local Measurement ◽  
Microwave Background ◽  
Random Samples ◽  
Local Measurements ◽  
Grain Dust ◽  
Cmb Temperature

ABSTRACT It is possible to reduce the discrepancy between the local measurement of the cosmological parameter H0 and the value derived from the Planck measurements of the cosmic microwave background (CMB) by considering contamination of the CMB by emission from some medium around distant extragalactic sources, such as extremely cold coarse-grain dust. Though being distant, such a medium would still be in the foreground with respect to the CMB, and, as any other foreground, it would alter the CMB power spectrum. This could contribute to the dispersion of CMB temperature fluctuations. By generating a few random samples of CMB with different dispersions, we have checked that the increased dispersion leads to a smaller estimated value of H0, the rest of the cosmological model parameters remaining fixed. This might explain the reduced value of the Planck-derived parameter H0 with respect to the local measurements. The signature of the distant foreground in the CMB traced by supernovae (SNe) was previously reported by the authors of this paper – we found a correlation between the SN redshifts, zSN, and CMB temperature fluctuations at the SNe locations, TSN. Here we have used the slopes of the regression lines $T_{\rm SN}\, /\, z_{\rm SN}$ corresponding to different Planck wavebands in order to estimate the possible temperature of the distant extragalactic medium, which turns out to be very low, about 5 K. The most likely ingredient of this medium is coarse-grain (grey) dust, which is known to be almost undetectable, except for the effect of dimming remote extragalactic sources.

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