3629998
Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, & Basic Results
We present new full-sky temperature and polarization maps in five frequency bands from 23 to 94 GHz, based on data from the first five years of the WMAP sky survey. The new maps are consistent with previous maps and are more sensitive. The five-year maps incorporate several improvements in data processing made possible by the additional years of data and by a more complete analysis of the instrument calibration and in-flight beam response. We present several new tests for systematic errors in the polarization data and conclude that W band polarization data is not yet suitable for cosmological studies, but we suggest directions for further study. We do find that Ka band data is suitable for use; in conjunction with the additional years of data, the addition of Ka band to the previously used Q and V band channels significantly reduces the uncertainty in the optical depth parameter. Further scientific results from the five year data analysis are presented in six companion papers and are summarized in �7 of this paper.
15659295
The amplitude and spectral index of the large angular scale anisotropy in the cosmic microwave background radiation
In many cosmological models, the large angular scale anisotropy in the cosmic microwave background is parameterized by a spectral index, $n$, and a quadrupolar amplitude, $Q$. For a Peebles-Harrison-Zel'dovich spectrum, $n=1$. Using data from the Far Infra-Red Survey (FIRS) and a new statistical measure, a contour plot of the likelihood for cosmological models for which $-1 2.2$, as it is for $Q 44$.
15136222
DESIGN, IMPLEMENTATION AND TESTING OF THE MAP RADIOMETERS
The Microwave Anisotropy Probe (MAP) satellite, launched June 30, 2001, will produce full sky maps of the cosmic microwave background radiation in 5 frequency bands spanning 20 106 GHz. MAP contains 20 differential radiometers built with High Electron Mobility Transistor (HEMT) amplifiers with passively cooled input stages. The design and test techniques used to evaluate and minimize systematic errors and the pre-launch performance of the radiometers for all five bands are presented. Subject headings: cosmology: cosmic microwave background—instrumentation: detectors—space vehicles: instruments
6629905
THE OPTICAL DESIGN AND CHARACTERIZATION OF THE MICROWAVE ANISOTROPY PROBE
The primary goal of theMAP satellite, now in orbit, is to make high fidelity polarizatio n sensitive maps of the full sky in five frequency bands between 20 and 100 GHz. From th ese maps we will characterize the properties of the cosmic microwave background (CMB) anisotropy and Galac tic nd extragalactic emission on angular scales ranging from the effective beam size, < 0: Æ23, to the full sky. MAP is a differential microwave radiometer. Two back-to-back shaped offset Gregorian telescopes feed t wo mirror symmetric arrays of ten corrugated feeds. We describe the prelaunch design and characterization of th e optical system, compare the optical models to the measurements, and consider multiple possible sources of sy stematic error.
118946449
An Absolute Measurement of the Cosmic Microwave Background Radiation Temperature at 10.7 GHz
A balloon-borne experiment has measured the absolute temperature of the cosmic microwave background radiation (CMBR) at 10.7 GHz to be TCMBR = 2.730 ± 0.014 K. The error is the quadratic sum of several systematic errors, with a statistical error of less than 0.1 mK. The instrument is made up of a cooled corrugated horn antenna coupled to a total power radiometer. A cryogenic mechanical waveguide switch alternately connects the radiometer to the horn and to an internal reference load. The small measured temperature difference (20 mK) between the sky signal and the reference load in conjunction with the use of a cold front end keeps systematic instrumental corrections small. Atmospheric and window emission are minimized by flying the instrument at 24 km altitude. A large outer ground screen and smaller inner screen shield the instrument from stray radiation from the ground and the balloon. In-flight tests constrain the magnitude of ground radiation contamination, and low-level interference is monitored through observations in several narrow-frequency bands.
17131606
Calibration of the Far Infrared Absolute Spectrophotometer ( FIRAS ) on the Cosmic Background Explorer ( COBE 1 )
The FIRAS instrument on the COBE satellite was designed to accurately measure the spectrum of the cosmic microwave background radiation (CMBR) in the frequency range 1 to 95 cm ?1 with an angular resolution of 7. We describe the calibration of this instrument, including the method of obtaining calibration data, reduction of data, the instrument model, tting the model to the calibration data, and application of the resulting model solution to sky observations. The instrument model ts well for calibration data which resemble sky conditions. The method of propagating detector noise through the calibration process to yield a covariance matrix of the calibrated sky data is described. The nal uncertainties are variable both in frequency and position, but for a typical calibrated sky 2:6 square pixel and 0.7 cm ?1 spectral element the random detector noise limit is of order of a few times 1 The National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC) is responsible for the design, development, and operation of the Cosmic Background Explorer (COBE). Scientiic guidance is provided by the COBE Science Working Group. GSFC is also responsible for the development of the analysis software and for the production of the mission data sets. { 2 { 10 ?7 erg cm ?2 s ?1 sr ?1 cm for 2 to 20 cm ?1 , and the diierence between the sky and the best t cosmic blackbody can be measured with a gain uncertainty of less than 3%.
118653169
Joint reconstruction of galaxy clusters from gravitational lensing and thermal gas II. Inversion of the thermal Sunyaev-Zel'dovich effect
This paper continues a series in which we intend to show how all observables of galaxy clusters can be combined to recover the twodimensional, projected gravitational potential of individual clusters. Our goal is to develop a non-parametric algorithm for joint cluster reconstruction taking all cluster observables into account. In this paper, we begin with the relation between the Compton-y parameter and the Newtonian gravitational potential, assuming hydrostatic equilibrium and a polytropic stratification of the intracluster gas. We show how Richardson-Lucy deconvolution can be used to convert the intensity change of the CMB due to the thermal SunyaevZel’dovich e ect into an estimate for the two-dimensional gravitational potential. Synthetic data simulated with characteristics of the ALMA telescope show that the two-dimensional potential of a cluster with mass 5 10 14 h 1 M at redshift 0:2 is possible with an error of . 5 % between the cluster centre and a radius r . 0:9h 1 Mpc.
58908723
Reconstructing the projected gravitational potential of galaxy clusters from galaxy kinematics
We have developed a method for reconstructing the two-dimensional, projected gravitational potential of galaxy clusters from observed line-of-sight velocity dispersions of cluster galaxies. It is the second in an intended series of papers aiming at a unique reconstruction method for cluster potentials that combine lensing, X-ray, Sunyaev-Zel’dovich and kinematic data. The observed galaxy velocity dispersions are deprojected using the Richardson-Lucy algorithm. The obtained radial velocity dispersions are then related to the gravitational potential by using the tested assumption of a polytropic relation between the e ective galaxy pressure and the density. Once the gravitational potential is obtained in three dimensions, projection along the line of sight yields the two-dimensional potential. For simplicity we adopt spherical symmetry and a known profile for the anisotropy parameter of the galaxy velocity dispersions. We tested the method with a numerically simulated galaxy cluster and the galaxies identified therein and performed the reconstruction for three di erent lines of sight. We extracted a projected velocity-dispersion profile from the simulated cluster and passed it through our algorithm, showing that the deviation between the true and the reconstructed gravitational potential is< 10% within 1:5h 1 Mpc from the cluster centre.