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 Cosmology with the cosmic microwave background temperature-polarization correlation

2017 ◽  
Vol 602 ◽  
pp. A41 ◽  
Author(s):  
F. Couchot ◽  
S. Henrot-Versillé ◽  
O. Perdereau ◽  
S. Plaszczynski ◽  
B. Rouillé d’Orfeuil ◽  
...  
Keyword(s):  
Cosmic Microwave Background ◽  
Cosmological Parameters ◽  
Power Spectra ◽  
Microwave Background ◽  
Instrumental Noise ◽  
Cosmic Microwave Background Temperature ◽  
Temperature Polarization ◽  
Background Temperature ◽  
The Impact ◽  
Polarization Correlation

We demonstrate that the cosmic microwave background (CMB) temperature-polarization cross-correlation provides accurate and robust constraints on cosmological parameters. We compare them with the results from temperature or polarization and investigate the impact of foregrounds, cosmic variance, and instrumental noise. This analysis makes use of the Planck high-ℓ HiLLiPOP likelihood based on angular power spectra, which takes into account systematics from the instrument and foreground residuals directly modelled using Planck measurements. The temperature-polarization correlation (TE) spectrum is less contaminated by astrophysical emissions than the temperature power spectrum (TT), allowing constraints that are less sensitive to foreground uncertainties to be derived. For ΛCDM parameters, TE gives very competitive results compared to TT. For basic ΛCDM model extensions (such as AL, ∑mν, or Neff), it is still limited by the instrumental noise level in the polarization maps.

scholarly journals Cosmic microwave background: probing the universe from z = 6 to 1100

2006 ◽  
Vol 2 (14) ◽  
pp. 254-254
Author(s):  
David N. Spergel
Keyword(s):  
Cosmic Microwave Background ◽  
Initial Conditions ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Line Of Sight ◽  
Microwave Background ◽  
Physical Conditions ◽  
Cosmic Microwave Background Temperature ◽  
Background Temperature ◽  
The Universe

Observations of cosmic microwave background temperature and polarization fluctuations are sensitive to both physical conditions at recombination (z = 1100) and physical process along the line of sight. I will discuss recent results from the Wilkinson Microwave Anisotropy Probe and planned ground and space-based observations. The talk will emphasize the role of CMB observations in determining the initial conditions for the growth of structure and as a probe of the physics of re-ionization.

scholarly journals The evolution of the cosmic microwave background temperature

2011 ◽  
Vol 526 ◽  
pp. L7 ◽  
Author(s):  
P. Noterdaeme ◽  
P. Petitjean ◽  
R. Srianand ◽  
C. Ledoux ◽  
S. López
Keyword(s):  
Cosmic Microwave Background ◽  
Microwave Background ◽  
Cosmic Microwave Background Temperature ◽  
Background Temperature

scholarly journals Decaying Dark Energy in Light of the Latest Cosmological Dataset

Symmetry ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 372 ◽  
Author(s):  
Ivan de Martino
Keyword(s):  
Dark Energy ◽  
Cosmic Microwave Background ◽  
Parameter Space ◽  
Hubble Constant ◽  
Two Dimensions ◽  
Matter Density ◽  
Microwave Background ◽  
Energy Models ◽  
Cosmic Microwave Background Temperature ◽  
Background Temperature

Decaying Dark Energy models modify the background evolution of the most common observables, such as the Hubble function, the luminosity distance and the Cosmic Microwave Background temperature–redshift scaling relation. We use the most recent observationally-determined datasets, including Supernovae Type Ia and Gamma Ray Bursts data, along with H ( z ) and Cosmic Microwave Background temperature versus z data and the reduced Cosmic Microwave Background parameters, to improve the previous constraints on these models. We perform a Monte Carlo Markov Chain analysis to constrain the parameter space, on the basis of two distinct methods. In view of the first method, the Hubble constant and the matter density are left to vary freely. In this case, our results are compatible with previous analyses associated with decaying Dark Energy models, as well as with the most recent description of the cosmological background. In view of the second method, we set the Hubble constant and the matter density to their best fit values obtained by the Planck satellite, reducing the parameter space to two dimensions, and improving the existent constraints on the model’s parameters. Our results suggest that the accelerated expansion of the Universe is well described by the cosmological constant, and we argue that forthcoming observations will play a determinant role to constrain/rule out decaying Dark Energy.

scholarly journals Relieving tensions related to the lensing of the cosmic microwave background temperature power spectra

2017 ◽  
Vol 597 ◽  
pp. A126 ◽  
Author(s):  
F. Couchot ◽  
S. Henrot-Versillé ◽  
O. Perdereau ◽  
S. Plaszczynski ◽  
B. Rouillé d’Orfeuil ◽  
...  
Keyword(s):  
Cosmic Microwave Background ◽  
Power Spectra ◽  
Microwave Background ◽  
Cosmic Microwave Background Temperature ◽  
Background Temperature
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