scholarly journals A new line-of-sight approach to the non-linear Cosmic Microwave Background

2015 ◽  
Vol 2015 (04) ◽  
pp. 037-037 ◽  
Author(s):  
Christian Fidler ◽  
Kazuya Koyama ◽  
Guido W. Pettinari
Keyword(s):  
Cosmic Microwave Background ◽  
Line Of Sight ◽  
Microwave Background ◽  
Non Linear

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 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 A Supervoid Explanation of the Cosmic Microwave Background Cold Spot

2014 ◽  
Vol 10 (S306) ◽  
pp. 153-155
Author(s):  
F. Finelli ◽  
J. García-Bellido ◽  
A. Kovács ◽  
F. Paci ◽  
I. Szapudi
Keyword(s):  
Cosmic Microwave Background ◽  
Null Hypothesis ◽  
Angular Size ◽  
Line Of Sight ◽  
Cold Spot ◽  
Spherically Symmetric ◽  
Cold Region ◽  
Microwave Background ◽  
Texture Model ◽  
Region Filling

AbstractThe Cold Spot is an anomalously cold region in the Cosmic Microwave Background (Vielva et al. 2004), either caused by a structure in the line of sight or could be of primordial origin. We search for a supervoid aligned with the Cold Spot region, filling the gap in redshift at z<0.3 which has never been explored in details. We find a large projected under density in the recently constructed WISE-2MASS catalogue, whose median redshift is z ≃ 0.14, with an angular size of 30 degrees. We show that a spherically symmetric Lemaitre-Tolman-Bondi (LTB) void model can simultaneously fit the δgal/b=δ2D≃ −0.12 underdensity in the WISE-2MASS catalogue, and the Cold Spot as observed by both the WMAP and Planck satellites. Such an LTB supervoid gives a plausible explanation of the Cold Spot anomaly, and is preferred over the null hypothesis or a texture model.

Polarization Signatures of Clusters in the Microwave Background

2005 ◽  
Vol 201 ◽  
pp. 445-446
Author(s):  
Anthony. Challinor
Keyword(s):  
Cosmic Microwave Background ◽  
Relativistic Electron ◽  
Compton Scattering ◽  
Galaxy Clusters ◽  
Frequency Spectrum ◽  
Velocity Dispersion ◽  
Electron Velocity ◽  
Line Of Sight ◽  
Microwave Background

Compton scattering of photons from ionised gas in galaxy clusters along the line of sight leaves an imprint in the polarization of the cosmic microwave background. We investigate this process taking account of the effects of relativistic electron velocity dispersion and primordial anisotropy on the frequency spectrum of the generated polarization. We also discuss the prospects of detecting such effects with the Planck survey.

scholarly journals MODELING X–RAY EMISSION OF A STRAIGHT JET: PKS 0920-397

2010 ◽  
Vol 19 (06) ◽  
pp. 879-885 ◽  
Author(s):  
D. A. SCHWARTZ ◽  
F. MASSARO ◽  
A. SIEMIGINOWSKA ◽  
D. M. WORRALL ◽  
M. BIRKINSHAW ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Radio Emission ◽  
Cosmic Microwave Background ◽  
Lorentz Factor ◽  
Line Of Sight ◽  
Relativistic Electrons ◽  
Microwave Background ◽  
X Ray ◽  
Inverse Compton ◽  
Doppler Factor

We summarize a study of PKS 0920-397 using our 42 ks Chandra observation in conjunction with our ATCA 20GHz image, and HST/ACS F814W and F475W images. We investigate the hypothesis that the jet X–ray emission is due to inverse-Compton (IC) scattering on the cosmic microwave background (CMB) from the same population of relativistic electrons that give rise to the radio emission. To calculate parameters intrinsic to the source, one must finesse the fact that we do not know the true angle of the jet to our line of sight. Typical assumptions are that the Doppler factor equals the bulk Lorentz factor, or that the Lorentz factor takes some fixed numerical value. While giving useful estimates, neither assumption can be exact in general. We try different constraints to determine the jet quantities. It is plausible that the kinetic flux is constant along the jet, prior to a terminal hotspot or lobe, and with minimal bending of the jet. Alternatively, because PKS 0920-397 appears straight in projection on the sky, we might assume the jet maintains a constant angle to our line of sight. Either approach gives bulk Lorentz factors of 6 to 8, with kinetic energy flux of order 1046 erg s-1, and with the jet at an angle 2° to 4° from our line of sight.

Small‐Scale Cosmic Microwave Background Observations at 8.4 GHz

1997 ◽  
Vol 483 (1) ◽  
pp. 38-50 ◽  
Author(s):  
R. Bruce Partridge ◽  
Eric A. Richards ◽  
Edward B. Fomalont ◽  
K. I. Kellerman ◽  
Rogier A. Windhorst
Keyword(s):  
Cosmic Microwave Background ◽  
Small Scale ◽  
Microwave Background
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