Download or read book Measurements of the Cosmic Microwave Background Temperature at 1 47 GHz written by and published by . This book was released on 1991 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: A radiofrequency-gain total power radiometer measured the intensity of the cosmic microwave background (CMB) at a frequency of 1.47 GHz (20.4 cm wavelength) from White Mountain, California, in September 1988 and from the South Pole, Antarctica, in December 1989. The CMB thermodynamic temperature, TCMB, is 2.27 {plus minus} 0.25 K (68% C.L.) measured from White Mountain and 2.26 {plus minus} 0.21 K from the South Pole site. The combined result is 2.27 {plus minus} 0.19 K. The correction for galactic emission has been derived from scaled low-frequency maps and constitutes the main source, of error. The atmospheric signal is found by extrapolation from zenith scan measurements at higher frequencies. The result is consistent with previous low-frequency measurements, including a measurement at 1.41 GHz (Levin et al. 1988) made with an earlier version of this instrument. The result is -2.5? ( -l% probability) from the 2.74 {plus minus} 0.02,K global average CMB temperature.

Download or read book Measurements of the Cosmic Microwave Background Temperature At1 47 GHz written by and published by . This book was released on 1992 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurements of the Cosmic Microwave Background Temperature at 1 47 GHz written by Marc John Bensadoun and published by . This book was released on 1991 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spectral Measurements of the Cosmic Microwave Background written by Alan John Kogut and published by . This book was released on 1989 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement of the Cosmic Microwave Background Temperature and Galactic Emission at 8 0 and 8 3 GHZ with the ARCADE 2 Experiment written by Jack Edward Singal and published by . This book was released on 2006 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents a measurement of the radiometric temperature of the Cosmic Microwave Background (CMB) and of the intensity of Galactic emission at 8.1 and 8.3 GHz. These are the science results of the first flight of the ARCADE 2 instrument, on which the author's design, fabrication, and data analysis work forms the basis of this dissertation.

Download or read book The Temperature of the Cosmic Microwave Background Radiation At3 8 GHz Results of a Measurement from the South Pole Site written by and published by . This book was released on 1991 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurements of the Anisotropy of the Cosmic Microwave Background Radiation on Degree Angular Scales written by Andre Charles Clapp and published by . This book was released on 1994 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Cosmic Microwave Background written by Júlio C. Fabris and published by Springer. This book was released on 2016-10-07 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series of texts composing this book is based on the lectures presented during the II José Plínio Baptista School of Cosmology, held in Pedra Azul (Espírito Santo, Brazil) between 9 and 14 March 2014. This II JBPCosmo has been entirely devoted to the problem of understanding theoretical and observational aspects of Cosmic Background Radiation (CMB).The CMB is one of the most important phenomena in Physics and a fundamental probe of our Universe when it was only 400,000 years old. It is an extraordinary laboratory where we can learn from particle physics to cosmology; its discovery in 1965 has been a landmark event in the history of physics.The observations of the anisotropy of the cosmic microwave background radiation through the satellites COBE, WMAP and Planck provided a huge amount of data which are being analyzed in order to discover important informations regarding the composition of our universe and the process of structure formation.

Download or read book A Low frequency Measurement of the Spectrum of the Cosmic Microwave Background Radiation written by Steven Mark Levin and published by . This book was released on 1987 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Measurement of the Temperature of the Cosmic MicrowaveBackground at a Frequency of 7 5 GHz written by and published by . This book was released on 1989 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured the intensity of the cosmic microwave background (CMB) at a frequency of 7.5 GHz (wavelength 4.0 cm) using a ground-based, total power radiometer calibrated at the horn aperture by an external cryogenic reference target. The radiometer measured the difference in antenna temperature between the reference target and the zenith sky from a dry, high-altitude site. Subtraction of foreground signals (primarily atmospheric and galactic emission) measured with the same instrument leaves the CMB as the residual. The radiometer measured the atmospheric antenna temperature by correlating the signal change with the airmass in the beam during tip scans. The small galactic signal was subtracted based on extrapolation from lower frequencies, and was checked by differential drift scans. The limiting uncertainty in the CMB measurement was the effect of ground radiation in the antenna sidelobes during atmospheric measurements. The thermodynamic temperature of the CMB at 7.5 GHz is 2.59 ± 0.07 K (68% confidence level).

Download or read book Low frequency Measurements of the CMB cosmic Microwave Background Spectrum written by and published by . This book was released on 1989 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of an extended program to characterize the spectrum of the cosmic microwave background (CMB) at low frequencies, we have performed multiple measurements from a high-altitude site in California. On average, these measurements suggest a CMB temperature slightly lower than measurements at higher frequencies. Atmospheric conditions and the encroachment of civilization are now significant limitations from our present observing site. In November 1989, we will make new measurements from the South Pole Amnudsen-Scott Station at frequencies 0.82 1.5, 2.5, 3.8, 7.5, and 90 GHz. We discuss recent measurements and indicate improvements from a polar observing site. 11 refs., 2 figs.

Download or read book Spectral Measurements of the Cosmic Microwave Background written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Three experiments have measured the intensity of the Cosmic Microwave Background (CMB) at wavelengths 4.0, 3.0, and 0.21 cm. The measurement at 4.0 cm used a direct-gain total-power radiometer to measure the difference in power between the zenith sky and a large cryogenic reference target. Foreground signals are measured with the same instrument and subtracted from the zenith signal, leaving the CMB as the residual. The reference target consists of a large open-mouth cryostat with a microwave absorber submerged in liquid helium; thin windows block the radiative heat load and prevent condensation atmospheric gases within the cryostat. The thermodynamic temperature of the CMB at 4.0 cm is 2.59 +- 0.07 K. The measurement at 3.0 cm used a superheterodyne Dicke-switched radiometer with a similar reference target to measure the zenith sky temperature. A rotating mirror allowed one of the antenna beams to be redirected to a series of zenith angles, permitting automated atmospheric measurements without moving the radiometer. A weighted average of 5 years of data provided the thermodynamic temperature of the CMB at 3.0 cm of 2.62 +- 0.06 K. The measurement at 0.21 cm used Very Large Array observations of interstellar ortho-formaldehyde to determine the CMB intensity in molecular clouds toward the giant HII region W51A (G49.5-0.4). Solutions of the radiative transfer problem in the context of a large velocity gradient model provided estimates of the CMB temperature within the foreground clouds. Collisional excitation from neutral hydrogen molecules within the clouds limited the precision of the result. The thermodynamic temperature of the CMB at 0.21 cm is 3.2 +- 0.9 K. 72 refs., 27 figs., 38 tabs.

Download or read book Thermal Asymmetry of the Cosmic Microwave Background Radiation written by Igorʹ Nikolaevich Taganov and published by . This book was released on 2008 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Analysis of Recent Measurements of the Temperature of TheCosmic Microwave Background Radiation written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents an analysis of the results of recent temperature measurements of the cosmic microwave background radiation (CMBR). The observations for wavelengths longer than 0.1 cm are well fit by a blackbody spectrum at 2.74 ± 0.02 K; however, including the new data of Matsumoto et al. (1987) the result is no longer consistent with a Planckian spectrum. The data are described by a Thomson-distortion parameter u = 0.021 ± 0.002 and temperature 2.823 ± 0.010 K at the 68% confidence level. Fitting the low-frequency data to a Bose-Einstein spectral distortion yields a 95% confidence level upper limit of 1.4 x 10−2 on the chemical potential [mu]0. These limits on spectral distortions place restrictions on a number of potentially interesting sources of energy release to the CMBR, including the hot intergalactic medium proposed as the source of the X-ray background.

Download or read book A Precise Measurement of the Cosmic Microwave Background Radiation Temperature at 2 64 Millimeters written by Mary Elizabeth Anne Kaiser and published by . This book was released on 1990 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Measurements of the Spectrum of the Cosmic Microwave Background written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate measurements of the spectrum of the cosmic microwave background (CMB) can provide useful tests of cosmological theories. The data set existing in 1982 has been summarized on a number of occasions and is shown. To first approximation the CMB is characterized by a single temperature and thus has a blackbody spectrum over the frequency range from 0.02 to 24 cm−1. The error limits given for these experiments are dominated by systematic errors and are often very subjective. Consequently, it is not clear how to analyze the data set in a valid way. The general impression, however, is of a scatter in the high frequency data that is somewhat larger than would be expected from the given error limits. We have designed a new apparatus to measure the spectrum of the CMB in the frequency range from 3 to 10 cm−1. 13 references, 5 figures.

Download or read book A Measurement of the Cosmic Microwave Background Temperature at 1 5 Cm Wavelength written by W. J. Welch and published by . This book was released on 1967 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report discusses the measurement of the cosmic microwave background temperature at 1.5 cm. wavelength; the result is 2.0 plus or minus 0.8 degrees K. Experimental techniques and the sources of error are mentioned.