Showing papers by "Edward L. Wright published in 2006"
TL;DR: In this article, a simple cosmological model with only six parameters (matter density, Omega_m h^2, baryon density, BH 2, Hubble Constant, H_0, amplitude of fluctuations, sigma_8, optical depth, tau, and a slope for the scalar perturbation spectrum, n_s) was proposed to fit the three-year WMAP temperature and polarization data.
Abstract: A simple cosmological model with only six parameters (matter density, Omega_m h^2, baryon density, Omega_b h^2, Hubble Constant, H_0, amplitude of fluctuations, sigma_8, optical depth, tau, and a slope for the scalar perturbation spectrum, n_s) fits not only the three year WMAP temperature and polarization data, but also small scale CMB data, light element abundances, large-scale structure observations, and the supernova luminosity/distance relationship. Using WMAP data only, the best fit values for cosmological parameters for the power-law flat LCDM model are (Omega_m h^2, Omega_b h^2, h, n_s, tau, sigma_8) = 0.1277+0.0080-0.0079, 0.02229+-0.00073, 0.732+0.031-0.032, 0.958+-0.016, 0.089+-0.030, 0.761+0.049-0.048). The three year data dramatically shrink the allowed volume in this six dimensional parameter space. Assuming that the primordial fluctuations are adiabatic with a power law spectrum, the WMAP data_alone_ require dark matter, and favor a spectral index that is significantly less than the Harrison-Zel'dovich-Peebles scale-invariant spectrum (n_s=1, r=0). Models that suppress large-scale power through a running spectral index or a large-scale cut-off in the power spectrum are a better fit to the WMAP and small scale CMB data than the power-law LCDM model; however, the improvement in the fit to the WMAP data is only Delta chi^2 = 3 for 1 extra degree of freedom. The combination of WMAP and other astronomical data yields significant constraints on the geometry of the universe, the equation of state of the dark energy, the gravitational wave energy density, and neutrino properties. Consistent with the predictions of simple inflationary theories, we detect no significant deviations from Gaussianity in the CMB maps.
6,295 citations
TL;DR: A cosmology calculator that computes times and distances as a function of redshift for user-defined cosmological parameters has been made available online as mentioned in this paper, which allows one to specify the equation-of-state parameter w and, and one for converting the light-travel times usually given in the popular press into redshifts.
Abstract: A cosmology calculator that computes times and distances as a function of redshift for user- defined cosmological parameters has been made available online. This paper gives the formulae used by the cosmology calculator and discusses some of its implementation. A version of the calculator that allows one to specify the equation-of-state parameter w and , and one for converting the light-travel times usually given in � w the popular press into redshifts, is also located at the same site.
1,137 citations
TL;DR: In this article, a detailed description of the updated data processing that produces maximum likelihood sky map estimates is presented, along with the methods used to produce reduced resolution maps and corresponding noise covariance matrices.
Abstract: The WMAP satellite has completed 3 years of observations of the cosmic microwave background radiation. The 3-year data products include several sets of full sky maps of the Stokes I, Q and U parameters in 5 frequency bands, spanning 23 to 94 GHz, and supporting items, such as beam window functions and noise covariance matrices. The processing used to produce the current sky maps and supporting products represents a significant advancement over the first year analysis, and is described herein. Improvements to the pointing reconstruction, radiometer gain modeling, window function determination and radiometer spectral noise parametrization are presented. A detailed description of the updated data processing that produces maximum likelihood sky map estimates is presented, along with the methods used to produce reduced resolution maps and corresponding noise covariance matrices. Finally two methods used to evaluate the noise of the full resolution sky maps are presented along with several representative year-to-year null tests, demonstrating that sky maps produced from data from different observational epochs are consistent.
158 citations
TL;DR: A cosmology calculator that computes times and distances as a function of redshift for user-defined cosmological parameters is available on the World Wide Web as discussed by the authors, which allows one to specify the equation of state parameter w and w' and neutrino masses.
Abstract: A cosmology calculator that computes times and distances as a function of redshift for user-defined cosmological parameters is available on the World Wide Web. This note gives the formulae used by the cosmology calculator and discusses some of its implementation. A version of the calculator that allows one to specify the equation of state parameter w and w' and neutrino masses, and a version for converting the light travel times usually given in the popular press into redshifts are also available.
92 citations
Goddard Space Flight Center1, University of Toronto2, Johns Hopkins University3, Cornell University4, Princeton University5, University of British Columbia6, University of Texas at Austin7, University of Chicago8, Brown University9, University of Pennsylvania10, University of California, Los Angeles11
TL;DR: In this article, the first three years of the WMAP sky survey were used to estimate the angular power spectrum of the temperature anisotropy using a hybrid approach that combines a maximum likelihood estimate at low l (large angular scales) with a quadratic cross-power estimate for l>30.
Abstract: We present new full-sky temperature maps in five frequency bands from 23 to 94 GHz, based on the first three years of the WMAP sky survey The new maps, which are consistent with the first-year maps and more sensitive, incorporate improvements in data processing made possible by the additional years of data and by a more complete analysis of the polarization signal These include refinements in the gain calibration and beam response models We employ two forms of multi-frequency analysis to separate astrophysical foreground signals from the CMB, each of which improves on our first-year analyses First, we form an improved 'Internal Linear Combination' map, based solely on WMAP data, by adding a bias correction step and by quantifying residual uncertainties in the resulting map Second, we fit and subtract new spatial templates that trace Galactic emission; in particular, we now use low-frequency WMAP data to trace synchrotron emission The WMAP point source catalog is updated to include 115 new sources We derive the angular power spectrum of the temperature anisotropy using a hybrid approach that combines a maximum likelihood estimate at low l (large angular scales) with a quadratic cross-power estimate for l>30 Our best estimate of the CMB power spectrum is derived by averaging cross-power spectra from 153 statistically independent channel pairs The combined spectrum is cosmic variance limited to l=400, and the signal-to-noise ratio per l-mode exceeds unity up to l=850 The first two acoustic peaks are seen at l=2208 +- 07 and l=5309 +- 38, respectively, while the first two troughs are seen at l=4124 +- 19 and l=6751 +- 111, respectively The rise to the third peak is unambiguous; when the WMAP data are combined with higher resolution CMB measurements, the existence of a third acoustic peak is well established
75 citations
Princeton University1, Goddard Space Flight Center2, University of Texas at Austin3, University of Toronto4, Johns Hopkins University5, Cornell University6, University of British Columbia7, University of Chicago8, Brown University9, University of Pennsylvania10, University of California, Los Angeles11
TL;DR: In this paper, the authors present three-year full-sky maps of the polarization and analyze them for foreground emission and cosmological implications and find that the limit from the polarization signals alone is r<2.2 (95% CL) corresponding to a limit on the cosmic density of gravitational waves of Omega{GW}h^2 < 5 times 10−12.
Abstract: The Wilkinson Microwave Anisotropy Probe WMAP has mapped the entire sky in five frequency bands between 23 and 94 GHz with polarization sensitive radiometers. We present three-year full-sky maps of the polarization and analyze them for foreground emission and cosmological implications. These observations open up a new window for understanding the universe. WMAP observes significant levels of polarized foreground emission due to both Galactic synchrotron radiation and thermal dust emission. The least contaminated channel is at 61 GHz. Informed by a model of the Galactic foreground emission, we subtract the foreground emission from the maps. In the foreground corrected maps, for l=2-6, we detect l(l+1) C_l^{EE} / (2 pi) = 0.086 +-0.029 microkelvin^2. This is interpreted as the result of rescattering of the CMB by free electrons released during reionization and corresponds to an optical depth of tau = 0.10 +- 0.03. We see no evidence for B-modes, limiting them to l(l+1) C_l^{BB} / (2 pi) = -0.04 +- 0.03 microkelvin^2. We find that the limit from the polarization signals alone is r<2.2 (95% CL) corresponding to a limit on the cosmic density of gravitational waves of Omega_{GW}h^2 < 5 times 10^{-12}.
From the full WMAP analysis, we find r<0.55 (95% CL) corresponding to a limit of Omega_{GW}h^2 < 10^{-12} (95% CL).
58 citations
TL;DR: In this paper, color selection of rare objects in a wide-field, multiband survey spanning from the optical to the mid-infrared was discussed, and two of the most sought after astrophysical sources were identified in the IRAC Shallow Survey of the Bootes field of the NOAO Deep Wide-Field Survey.
Abstract: We discuss color selection of rare objects in a wide-field, multiband survey spanning from the optical to the mid-infrared. Simple color criteria simultaneously identify and distinguish two of the most sought after astrophysical sources: the coolest brown dwarfs and the most distant quasars. We present spectroscopically-confirmed examples of each class identified in the IRAC Shallow Survey of the Bootes field of the NOAO Deep Wide-Field Survey. ISS J142950.9+333012 is a T4.5 brown dwarf at a distance of approximately 42 pc, and ISS J142738.5+331242 is a radio-loud quasar at redshift z=6.12. Our selection criteria identify a total of four candidates over 8 square degrees of the Bootes field. The other two candidates are both confirmed 5.5
56 citations
University of California, Berkeley1, University of California, Santa Cruz2, Lawrence Berkeley National Laboratory3, Harvard University4, California Institute of Technology5, University of Arizona6, University of Nottingham7, Imperial College London8, National Radio Astronomy Observatory9, University of Victoria10, University of Sydney11, Space Telescope Science Institute12, National Taiwan University13, Stanford University14, University of California, Los Angeles15, University of Oxford16, Columbia University17, National Research Council18, Durham University19
TL;DR: The All-wavelength Extended Groth Strip International Survey (AEGIS) as discussed by the authors was designed to study the physical properties and evolutionary processes of galaxies at z = 1.5 - 10 keV.
Abstract: In this the first of a series of Letters, we present a description of the panchromatic data sets that have been acquired in the Extended Groth Strip region of the sky. Our survey, the All-wavelength Extended Groth strip International Survey (AEGIS), is intended to study the physical properties and evolutionary processes of galaxies at z ~ 1. It includes the following deep, wide-field imaging data sets: Chandra/ACIS X-ray (0.5 - 10 keV), GALEX ultraviolet (1200 - 2500 Angstrom), CFHT/MegaCam Legacy Survey optical (3600 - 9000 Angstroms), CFHT/CFH12K optical (4500 - 9000 Angstroms), Hubble Space Telescope/ACS optical (4400 - 8500 Angstroms), Palomar/WIRC near-infrared (1.2 - 2.2 microns), Spitzer/IRAC mid-infrared (3.6 - 8.0 microns), Spitzer/MIPS far-infrared (24 - 70 microns), and VLA radio continuum (6 - 20 cm). In addition, this region of the sky has been targeted for extensive spectroscopy using the DEIMOS spectrograph on the Keck II 10 m telescope. Our survey is compared to other large multiwavelength surveys in terms of depth and sky coverage.
31 citations
TL;DR: In this article, the angular power spectrum of resolved sources at 3.6 microns (L-band) in Spitzer imaging data of the Goodfellow HDF-N, the GOODS CDF-S, and the NDWFS Bootes field in several source magnitude bins is described.
Abstract: We describe the angular power spectrum of resolved sources at 3.6 microns (L-band) in Spitzer imaging data of the GOODS HDF-N, the GOODS CDF-S, and the NDWFS Bootes field in several source magnitude bins. We also measure angular power spectra of resolved sources in the Bootes field at K_S and J-bands using ground-based IR imaging data. In the three bands, J, K_S, and L, we detect the clustering of galaxies on top of the shot-noise power spectrum at multipoles between ell ~ 10^2 and 10^5. The angular power spectra range from the large, linear scales to small, non-linear scales of galaxy clustering, and in some magnitude ranges, show departure from a power-law clustering spectrum. We consider a halo model to describe clustering measurements and to establish the halo occup ation number parameters of IR bright galaxies at redshifts around one. We also extend our clustering results and completeness-corrected faint source number counts in GOODS fields to understand the underlying nature of unresolved sources responsible for IR background (IRB) anisotropies that were detected in deep Spitzer images. While these unresolved fluctuations were measured at sub-arcminute angular scales, if a high-redshift diffuse component associated with first galaxies exists in the IRB, then it's clustering properties are best studied with shallow, wide-field images that allow a measurement of the clustering spectrum from a few degrees to arcminute angular scales.
27 citations
TL;DR: The Wide-Field Infrared Survey Explorer (WISE) is a NASA MIDEX mission that will survey the entire sky in four bands from 3.3 to 23 microns with a sensitivity 1000 times greater than the IRAS survey.
Abstract: The Wide-field Infrared Survey Explorer (WISE), a NASA MIDEX mission, will survey the entire sky in four bands from 3.3 to 23 microns with a sensitivity 1000 times greater than the IRAS survey. The WISE survey will extend the Two Micron All Sky Survey into the thermal infrared and will provide an important catalog for the James Webb Space Telescope. Using 1024(sup 2) HgCdTe and Si:As arrays at 3.3, 4.7, 12 and 23 microns, WISE will find the most luminous galaxies in the universe, the closest stars to the Sun, and it will detect most of the main belt asteroids larger than 3 km. The single WISE instrument consists of a 40 cm diamond-turned aluminum afocal telescope, a two-stage solid hydrogen cryostat, a scan mirror mechanism, and reimaging optics giving 5 resolution (full-width-half-maximum). The use of dichroics and beamsplitters allows four color images of a 47' x47' field of view to be taken every 8.8 seconds, synchronized with the orbital motion to provide total sky coverage with overlap between revolutions. WISE will be placed into a Sun-synchronous polar orbit on a Delta 7320-10 launch vehicle. The WISE survey approach is simple and efficient. The three-axis-stabilized spacecraft rotates at a constant rate while the scan mirror freezes the telescope line of sight during each exposure. WISE has completed its mission Preliminary Design Review and its NASA Confirmation Review, and the project is awaiting confirmation from NASA to proceed to the Critical Design phase. Much of the payload hardware is now complete, and assembly of the payload will occur over the next year. WISE is scheduled to launch in late 2009; the project web site can be found at www.wise.ssl.berkeley.edu.
14 citations
TL;DR: The challenges to manage a high data rate, cryogenic, low earth-orbit mission; maintaining safe on-orbit operations, fast anomaly recoveries, production and dissemination of high quality science products, given the constraints imposed by funding profiles for small space missions are described.
Abstract: The goal of the Wide-field Infrared Survey Explorer (WISE) mission is to perform a highly sensitive all-sky survey in 4 wavebands from 3 to 25(mu)m. Launched on a Delta II rocket into a 500km Sun-synchronous orbit in June 2009, during its 7 months of operations, WISE will acquire about 50GBytes of raw science data every day, which will be down-linked via the TDRSS relay satellite system and processed into an astronomical catalogue and image atlas. The WISE mission operations system is being implemented in collaboration between UCLA, JPL and IPAC (Caltech). In this paper we describe the challenges to manage a high data rate, cryogenic, low earth-orbit mission; maintaining safe on-orbit operations, fast anomaly recoveries (mandated by the desire to provide complete sky coverage in a limited lifetime), production and dissemination of high quality science products, given the constraints imposed by funding profiles for small space missions.
University of Oklahoma1, Space Telescope Science Institute2, Columbia University3, Jet Propulsion Laboratory4, University of Notre Dame5, Rockwell Automation6, Goddard Space Flight Center7, Carnegie Institution for Science8, California Institute of Technology9, University of Texas at Austin10, University of California, Los Angeles11
TL;DR: Joint Efficient Dark Energy Investigation (JEDI) is a candidate implementation of the NASA-DOE Joint Dark Energy Mission (JDEM) as mentioned in this paper, which will probe the effects of dark energy in three independent ways: (1) using Type Ia supernovae as cosmological standard candles over a range of distances, (2) using baryon acoustic oscillations as a cosmology standard ruler over several cosmic epochs, and (3) mapping the weak gravitational lensing distortion by foreground galaxies of the images of background galaxies at different distances.
Abstract: The Universe appears to be expanding at an accelerating rate, driven by a mechanism called Dark Energy The nature of Dark Energy is largely unknown and needs to be derived from observation of its effects JEDI (Joint Efficient Dark-energy Investigation) is a candidate implementation of the NASA-DOE Joint Dark Energy Mission (JDEM) It will probe the effects of Dark Energy in three independent ways: (1) using Type Ia supernovae as cosmological standard candles over a range of distances, (2) using baryon acoustic oscillations as a cosmological standard ruler over a range of cosmic epochs, and (3) mapping the weak gravitational lensing distortion by foreground galaxies of the images of background galaxies at different distances JEDI provides crucial systematic error checks by simultaneously applying these three independent observational methods to derive the Dark Energy parameters The concordance of the results from these methods will not only provide an unprecedented understanding of Dark Energy, but also indicate the reliability of such an understanding JEDI will unravel the nature of Dark Energy by obtaining observations only possible from a vantage point in space, coupled with a unique instrument design and observational strategy Using a 2 meter-class space telescope with simultaneous wide-field imaging (~ 1 deg2, 08 to 42 μm in five bands) and multi-slit spectroscopy (minimum wavelength coverage 1 to 2 μm), JEDI will efficiently execute the surveys needed to solve the mystery of Dark Energy© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering Downloading of the abstract is permitted for personal use only
TL;DR: In the century since Einstein's anno mirabilis of 1905, our concept of the universe has expanded from Kapteyn's flattened disk of stars only 10 kpc across to an observed horizon about 30 Gpc across that is only a tiny fraction of an immensely large inflated bubble as mentioned in this paper.
Abstract: In the century since Einstein's anno mirabilis of 1905, our concept of the Universe has expanded from Kapteyn's flattened disk of stars only 10 kpc across to an observed horizon about 30 Gpc across that is only a tiny fraction of an immensely large inflated bubble. The expansion of our knowledge about the Universe, both in the types of data and the sheer quantity of data, has been just as dramatic. This talk will summarize this century of progress and our current understanding of the cosmos.
TL;DR: In this article, the angular power spectrum of unresolved 3.6 micron IR light in Spitzer GOODS fields is described with an extra component of z>8 sources with a IRB contribution around 0.4 nW m^-2 sr-1.
Abstract: We describe the angular power spectrum of unresolved 3.6 micron IR light in Spitzer GOODS fields. The amplitude of the anisotropy spectrum decreases with decreasing flux threshold to which resolved sources are removed from images. When all pixels brighter than a Vega magnitude of 24.6 are removed, the amplitude of the power spectrum at arcminute angular scales can be described with an extra component of z>8 sources with a IRB contribution around 0.4 nW m^-2 sr-1. The shape of the power spectrum, however, is more consistent with that expected for unresolved, faint galaxies at lower redshifts with Vega magnitudes fainter than 23 with a total 3.6 micron intensity between 0.1 to 0.8 nW m^-2 sr^-1. We confirm this assumption by showing that large-scale power decreases rapidly when the unresolved clustering spectrum is measured from a processed HDF-N IRAC image where locations of faint ACS sources with no IR counterparts were also masked. Based on resolved counts and unresolved fluctuations, we find that, at most, about 7.0 nW m^-2 sr^-1 can be ascribed to galaxies.