Thermal Sunyaev-Zeldovich Effect Research Articles

Spectral Distortion of Cosmic Microwave Background Radiation by Scattering on Hot Electrons: Exact Calculations

The spectral distortion of the cosmic microwave background radiation produced by the inverse Compton scattering on hot electrons in clusters of galaxies (thermal Sunyaev-Zeldovich effect) is calculated for arbitrary optical depth and electron temperature. The distortion is found by a numerical solution of the exact Boltzmann equation for the photon distribution function. In the limit of small optical depth and low electron temperature, our results confirm the previous analyses. In the opposite limits, our method is the only one that permits us to make accurate calculations.

Time Delay Effect on the Cosmic Background Radiation from Static Gravitational Potential of Clusters

We present a quantitative analysis of the time delay effect of the static gravitational potential of galaxy clusters on the cosmic background radiation (CBR). This is primarily motivated by growing observational evidence that clusters have essentially experienced no evolution since redshift z ≈ 1, indicating that the contribution of a time-dependent potential to the CBR anisotropy discussed in the literature could be rather small for dynamically relaxed clusters. Using the softened isothermal sphere model and the universal density profile for the mass distribution of rich clusters, we calculate the CBR anisotropy by the time delay effect and compare it with those generated by the thermal and kinematic Sunyaev-Zeldovich (S-Z) effects, as well as by the transverse motion of clusters. While it is unlikely that the time delay effect is detectable in the current S-Z measurement, because of its small amplitude of 10-6-10-7 and its achromaticity, it nevertheless leads to an uncertainty of ~10% in the measurement of the kinematic S-Z effect of clusters. Future cosmological application of the peculiar velocity of clusters to be measured through the S-Z effect should therefore take this uncertainty into account.

Cross‐Correlating the Sloan Digital Sky Survey with the Microwave Sky

While most of the microwave background (CMB) fluctuations on angular scales greater than a few arcminutes were generated at z > 800, the low-redshift universe does distort the microwave background. Since the Sloan Digital Sky Survey (SDSS) traces the structures in the low-redshift universe, we can gain additional insights into the physics of the low-redshift universe by cross-correlating microwave background maps with template maps produced from the SDSS. We present a formalism for cross-correlating data from the Microwave Anisotropy Probe (MAP) with the Sloan Survey for the thermal Sunyaev-Zeldovich (SZ) effect, the Integrated Sachs-Wolfe (ISW) effect, and weak lensing. This formalism is used to compute the signal-to-noise ratio for cross-correlating these effects with various classes of tracer objects from the SDSS. The anticipated samples of SDSS quasars and galaxies with photometrically determined redshifts are found to be good tracers for cross-correlating with the CMB. We find that the SZ-galaxy cross-correlation would give good constraints on pressure fluctuations in supercluster-scale gas. Cross-correlating weakly lensed quasars with maps of the convergence of the CMB is found to give strong constraints on Ω0 as well as the equation of state, w. We find that the ISW cross-correlation gives a poor signal-to-noise ratio using these techniques.

Forecasting foreground impact on cosmic microwave background measurements

We explore the possible impact of galactic and extragalactic foregrounds on measurements of the cosmic microwave background (CMB). We find that, given our present understanding of the foregrounds, they are unlikely qualitatively to affect the ability of the MAP and Planck satellites to determine the angular power spectrum of the CMB, the key statistic for constraining cosmological parameters. Sufficiently far from the galactic plane, the only foregrounds that will affect power spectrum determination with any significance are the extragalactic ones. For MAP we find that the most troublesome foregrounds are radio point sources and the thermal Sunyaev-Zeldovich (SZ) effect. For Planck they are these same radio point sources and the far infrared background. Prior knowledge of the statistics of the SZ component (via either theoretical calculation, or higher frequency observations of just a few per cent of the sky, such as will be achieved by balloon borne experiments) may significantly improve MAP's determination of the CMB power spectrum. We also explore the foreground impact on MAP and Planck polarization power spectrum measurements.

Radio Sources in Galaxy Clusters at 28.5 [CLC]GHz[/CLC

We present serendipitous detections of radio sources at 28.5 GHz (1 cm), which resulted from our program to image thermal Sunyaev-Zeldovich (SZ) effect in 56 galaxy clusters. We find 64 radio sources with fluxes down to 0.4 mJy, and within 250 arcseconds from the pointing centers. The spectral indices (S ~ \nu^-\alpha) of 54 sources with published low frequency flux densities range from -0.6 to 2 with a mean of 0.77, and a median of 0.84. Extending low frequency surveys of radio sources towards galaxy clusters CL 0016+16, Abell 665, and Abell 2218 to 28.5 GHz, and selecting sources with 1.4 GHz flux density greater than 7 mJy to form an unbiased sample, we find a mean spectral index of 0.71 and a median of 0.71. We find 4 to 7 times more sources predicted from a low frequency survey in areas without galaxy clusters. This excess cannot be accounted for by gravitational lensing of a background radio population by cluster potentials, indicating most of the detected sources are associated with galaxy clusters. For the cluster Abell 2218, the presence of unsubtracted radio sources with 28.5 GHz flux densities less than 0.5 mJy, can only contribute to temperature fluctuations at a level of 10 to 25 \muK. The corresponding error due to radio point source contamination in the Hubble constant derived through a combined analysis of 28.5 GHz SZ images and X-ray emission observations ranges from 1% to 6%.

Peculiar cluster velocities from measurements of the kinematic Sunyaev-Zeldovich effect

view Abstract Citations (57) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Peculiar Cluster Velocities from Measurements of the Kinematic Sunyaev-Zeldovich Effect Rephaeli, Yoel ; Lahav, Ofer Abstract A detailed discussion is given of the possibility of determining peculiar velocities of clusters of galaxies by measuring the kinematic Sunyaev- Zeldovich effect. From available optical and X-ray data we select a sample of clusters for which the effect might be measurable at the optimal frequency where the thermal Sunyaev-Zeldovich effect vanishes. Publication: The Astrophysical Journal Pub Date: May 1991 DOI: 10.1086/169950 Bibcode: 1991ApJ...372...21R Keywords: Galactic Clusters; Peculiar Galaxies; Relic Radiation; Astronomical Models; Evolution (Development); Velocity Measurement; Astrophysics; COSMIC BACKGROUND RADIATION; GALAXIES: CLUSTERING; GALAXIES: REDSHIFTS full text sources ADS | data products SIMBAD (11) NED (11)