Edward L. Wright

Bio: Edward L. Wright is an academic researcher from University of California, Los Angeles. The author has contributed to research in topics: Cosmic microwave background & Galaxy. The author has an hindex of 119, co-authored 649 publications receiving 128250 citations. Previous affiliations of Edward L. Wright include Princeton University & University of California, Berkeley.

The WISE principal investigator's perspective

Abstract: The Wide-field Infrared Survey Explorer (WISE) project has dominated my life for the last 12 years, and it has been an interesting, rewarding and frustrating experience. The first proposal was made in 1998, and the very good core team assembled then has continued to work on the project. Scientific satellites are almost always unique designs, and there were many challenges in building a one-of-a-kind system. But the rewards from a successful mission are new data on the Universe, and here WISE has really delivered. Data has been flowing in at 250 Gbits per day for most of 2010.

Design of a 670 GHz Extended Interaction Klystron

Abstract: The development of terahertz power amplifiers presents significant new challenges as it brings into focus design, fabrication, and measurement issues that are not important factors at lower frequencies. We will describe our design approach to meet these challenges with particular emphasis on a 0.67 THz Extended-Interaction Klystron (EIK) [1].

Microfabricated 220 GHz, 50W SERPENTINE waveguide amplifier using novel UV-LIGA beam tunnel technique

Abstract: Summary form only given. A 220 GHz, 50 W vacuum electron serpentine waveguide amplifier is under development utilizing an 11.7 kV, 120 mA electron beam. The amplifier showcases a novel microfabrication technique employing embedded polymer monofilaments to simultaneously fabricate the circuit and beam tunnel in a single UV-LIGA step [1] (U.S. Provisional Patent Application filed). The method shows promise for fabricating beam tunnels and circuits into the THz range. The cold testing of the circuit and window is being carried out at the U.S. Naval Research Laboratory, where the circuit is also being fabricated.

Characterizing Extrasolar Planetary Systems

Abstract: The quest to detect and characterize exoplanets, and learn how they form is one of the most exciting science challenges of this century, one that opens new horizons in human knowledge. To meet this challenge new approaches are needed both observationally and theoretically. This paper summarizes powerful new measurement techniques that will aid in this quest. In particular, we describe how dust structures in debris disks will reveal otherwise undetectable planets, how the atmospheres of non-transiting extrasolar gas and ice giant planets can be probed spectroscopically, how observations can be used to measure the gas dissipation timescale in protoplanetary disks, and how it will be possible to understand the mechanism that delivered water to the Earth’s surface. Sensitive, high angular resolution measurements in the mid-IR to submillimeter spectral range will be needed to exploit these promising techniques. Section 1 of this paper describes four new measurement techniques, each of which has the potential to improve vastly our understanding of exoplanets and the planet formation process. Section 2 summarizes the measurement capabilities needed to implement these techniques. 1.1 Image irregular structures in dusty debris disks to find and characterize exoplanets The locations, masses and orbits of unseen planets can be deduced from the shapes of structures in dusty debris disks and from temporal variations in these structures, just as new Saturnian moons were found after ring gaps and features divulged their hiding places. The orbits of dust grains in developing and established planetary systems (i.e., debris disks) are perturbed gravitationally by any planets that may be present. Orbital resonances with the planets shepherd the dust into clumpy circumstellar ring structures, which have been observed at visible to millimeter wavelengths. These circumstellar structures can be decoded to reveal a planet's mass and orbital parameters, as well as the dominant dust grain size in the disk. Planet-hunting methods reliant upon measurements of the radial or proper motion of a planet’s parent star, or on transits of the star, have been very successful, but these methods all favor the detection of planets in close orbits. A key virtue of the debris disk imagery method is its ability to reveal planets in distant orbits, and thereby enable a more complete census of extrasolar planetary systems. Our understanding of planet formation depends on the availability of such a census. a NASA GSFC; b Caltech; c NASA Postdoctoral Fellow; d Jet Propulsion Laboratory; e U Maryland; f NOAO; g Johns Hopkins U; h IPAC; i UCLA Interplanetary dust at orbital distances likely occupied by planets glows most brightly in the far-infrared spectral range ~20 – 60 μm. Main sequence stars are faint at these wavelengths, so the starlight needn’t be blocked to allow disk imaging. The Spitzer Space Telescope demonstrated the power of far-IR debris disk imagery. Spitzer resolved the nearest four debris disks, at distances of only a few parsecs (Figure 1a), but an important objective is to understand our own solar system in the context of a representative statistical sample of exoplanetary systems. By imaging the disks around stars of many spectral types we will learn how planet formation depends on stellar mass. To achieve this objective, it will be necessary to detect 1 AU structures in debris disks out to a distance of ~10 pc, implying an angular resolution requirement of 0.1 arcsec. ALMA will be well-suited spatially, but its measurements will be far into the Rayleigh-Jeans regime, where the thermal emission from interplanetary dust is relatively faint. JWST will probe debris disks at wavelengths close to the emission peak, but with only 1 arcsecond angular resolution. What is needed instead is a capability for 0.1 arcsecond images in the midto far-IR (Figure 1b). Figure 1 –Spitzer resolves four nearby debris disks, including Fomalhaut, shown here (a) at 24 and 70 μm. A far-IR observatory with angular resolution a hundred-fold better than that of Spitzer could provide clear images of a large statistical sample of debris disks, enabling discoveries of new planets and a great improvement in our understanding of the factors that influence the evolution of planetary systems. The model images in (b), based on Eps Eri but scaled to 30 pc, show the predicted far-IR emission at 40, 60, and 100 μm color-coded as blue, green, and red, respectively. The dust-trapping planet (+) is shown at two orbital phases, and the resonantly trapped dust grains can be seen to have moved. 1.2 Characterize gas and ice giant exoplanets to constrain models of planetary system formation To understand planet migration and gain insight into the planet formation process, it will be imperative to characterize giant exoplanets at all orbital radii. Recent Spitzer observations of transiting extrasolar giant planets demonstrate the value of IR spectroscopy as a tool to constrain a planet’s temperature structure and probe the composition of its atmosphere. Soon JWST observers will be able to use the same technique to probe dimmer planets and fainter spectral features. However, transiting planets tend to be in close orbits and preferentially tell us about “hot Jupiters.” Exoplanets in distant orbits, like the gas and ice giants in our own solar system, have a very low probability of being seen in transit. An alternative technique is needed to characterize such planets. The spectra of non-transiting giant exoplanets could be measured with a Michelson stellar interferometer equipped with a Fourier Transform Spectrometer, a so-called “double Fourier” interferometer. To such an instrument the planet’s light would appear as the modulating signal component when the baseline position angle is varied, while starlight would produce a stable fringe pattern. With sufficient signal-to-noise ratio, the planet’s interferogram could be extracted and Fourier transformed to obtain the desired spectrum, and the planet’s orbital position could be measured. In the far-IR, where the planet-to-star contrast ratio is at a maximum (Figure 2, left), starlight nulling is not necessary and detection is possible if the exoplanet is separated from the star by an angle greater than λ/2B, where λ is the wavelength and B is the length of the interferometric baseline. Taking Jupiter as an example (Figure 2, right), we can expect to detect broad NH3 bands, which dominate the spectrum from 40 to 100 μm, and to study the abundances of key chemical species such as water and methane. The observed spectra of giant planets, when coupled with independent planet mass estimates (e.g., from the debris disk sculpting method described above), will test models for planetary atmospheres and serve as an empirical set of spectral benchmarks. The proposed spectroscopic measurements will be challenging, but not more difficult than the differential measurements (star + planet minus star) required in the transiting technique. A structurally connected infrared interferometer of modest size (~40 m) could probe planets at 0.1 arcsec orbital radii (i.e., 1 AU at 10 pc). Figure 2. Left panel: The atmospheres of giant planets will be seen in highest contrast relative to their parent stars in the far-infrared. Right panel: This spectrum of Jupiter from the Cassini Composite Infrared Spectrometer shows CH4, NH3, and PH3 absorption lines and was used to place chemically interesting limits on the mole fractions of HF, HCl, HBr, and HI in the jovian troposphere. How common are planetary systems like our own? The discovery and characterization of planets in distant orbits around stars with a wide range of masses, ages and heavy element concentrations, will dramatically advance the burgeoning field of comparative planetology and provide stringent new tests of theoretical models for planet formation. 1.3 Observe the transition from protoplanetary to debris disks to learn the effects of gas dissipation on planet formation A white paper by Mundy et al. will discuss observational methods to probe the early phases of star and planetary system formation. Here we discuss the interesting transition phase between a gas-rich proto-planetary disk and an older debris disk from which the gas has vanished. When does gas dissipation occur, and how does this affect the migration of planetary bodies and the outcome of the planet formation process? How does the dissipation process depend on the heavy element composition of the protoplanetary nebula, the mass of the newborn star, and the environment in which star formation takes place? By measuring the gas contents of planet forming disks of various ages it will be possible to constrain the timescale for gas giant planet formation and the migration of planetary bodies of all sizes. Spitzer has already enabled pathfinding studies. The Herschel Space Observatory will observe disks in the far-infrared, measuring numerous lines from hydrides, such as CH and OH, and the strong [C I], [O I] and [C II] fine structure lines at 370, 146, 63 and 158 μm. When coupled with models, far-IR spectral line observations will give us new insight into the chemistry and physical conditions in young planet forming disks. The C/O ratio, derivable from these observations, is thought to affect the composition, surface chemistry, and perhaps the habitability of planets. Following closely behind Herschel, ALMA and JWST will play major roles in studies of gasrich and gas-poor disks. With ALMA we will be able to make spectral line maps in surrogate tracers of total gas density, such as CO and its less abundant isotopes. Unfortunately, total gas density estimates based upon measurements of such proxies can be significantly biased, as CO molecules can be photodissociated or frozen onto grain surfaces. JWST will attack this problem head-on by directly measuring the readily excited 17 and 28 μm rotational lines of H2. JWST will measure the total gas conte

The Herschel-SPIRE Legacy Survey (HSLS): the scientific goals of a shallow and wide submillimeter imaging survey with SPIRE

Abstract: A large sub-mm survey with Herschel will enable many exciting science opportunities, especially in an era of wide-field optical and radio surveys and high resolution cosmic microwave background experiments. The Herschel-SPIRE Legacy Survey (HSLS), will lead to imaging data over 4000 sq. degrees at 250, 350, and 500 micron. Major Goals of HSLS are: (a) produce a catalog of 2.5 to 3 million galaxies down to 26, 27 and 33 mJy (50% completeness; 5 sigma confusion noise) at 250, 350 and 500 micron, respectively, in the southern hemisphere (3000 sq. degrees) and in an equatorial strip (1000 sq. degrees), areas which have extensive multi-wavelength coverage and are easily accessible from ALMA. Two thirds of the of the sources are expected to be at z > 1, one third at z > 2 and about a 1000 at z > 5. (b) Remove point source confusion in secondary anisotropy studies with Planck and ground-based CMB data. (c) Find at least 1200 strongly lensed bright sub-mm sources leading to a 2% test of general relativity. (d) Identify 200 proto-cluster regions at z of 2 and perform an unbiased study of the environmental dependence of star formation. (e) Perform an unbiased survey for star formation and dust at high Galactic latitude and make a census of debris disks and dust around AGB stars and white dwarfs.

Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds

Abstract: We present a full-sky 100 μm map that is a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and confirmed point sources removed. Before using the ISSA maps, we remove the remaining artifacts from the IRAS scan pattern. Using the DIRBE 100 and 240 μm data, we have constructed a map of the dust temperature so that the 100 μm map may be converted to a map proportional to dust column density. The dust temperature varies from 17 to 21 K, which is modest but does modify the estimate of the dust column by a factor of 5. The result of these manipulations is a map with DIRBE quality calibration and IRAS resolution. A wealth of filamentary detail is apparent on many different scales at all Galactic latitudes. In high-latitude regions, the dust map correlates well with maps of H I emission, but deviations are coherent in the sky and are especially conspicuous in regions of saturation of H I emission toward denser clouds and of formation of H2 in molecular clouds. In contrast, high-velocity H I clouds are deficient in dust emission, as expected. To generate the full-sky dust maps, we must first remove zodiacal light contamination, as well as a possible cosmic infrared background (CIB). This is done via a regression analysis of the 100 μm DIRBE map against the Leiden-Dwingeloo map of H I emission, with corrections for the zodiacal light via a suitable expansion of the DIRBE 25 μm flux. This procedure removes virtually all traces of the zodiacal foreground. For the 100 μm map no significant CIB is detected. At longer wavelengths, where the zodiacal contamination is weaker, we detect the CIB at surprisingly high flux levels of 32 ± 13 nW m-2 sr-1 at 140 μm and of 17 ± 4 nW m-2 sr-1 at 240 μm (95% confidence). This integrated flux ~2 times that extrapolated from optical galaxies in the Hubble Deep Field. The primary use of these maps is likely to be as a new estimator of Galactic extinction. To calibrate our maps, we assume a standard reddening law and use the colors of elliptical galaxies to measure the reddening per unit flux density of 100 μm emission. We find consistent calibration using the B-R color distribution of a sample of the 106 brightest cluster ellipticals, as well as a sample of 384 ellipticals with B-V and Mg line strength measurements. For the latter sample, we use the correlation of intrinsic B-V versus Mg2 index to tighten the power of the test greatly. We demonstrate that the new maps are twice as accurate as the older Burstein-Heiles reddening estimates in regions of low and moderate reddening. The maps are expected to be significantly more accurate in regions of high reddening. These dust maps will also be useful for estimating millimeter emission that contaminates cosmic microwave background radiation experiments and for estimating soft X-ray absorption. We describe how to access our maps readily for general use.

Seven-year wilkinson microwave anisotropy probe (wmap *) observations: cosmological interpretation

Abstract: The combination of seven-year data from WMAP and improved astrophysical data rigorously tests the standard cosmological model and places new constraints on its basic parameters and extensions. By combining the WMAP data with the latest distance measurements from the baryon acoustic oscillations (BAO) in the distribution of galaxies and the Hubble constant (H0) measurement, we determine the parameters of the simplest six-parameter ΛCDM model. The power-law index of the primordial power spectrum is ns = 0.968 ± 0.012 (68% CL) for this data combination, a measurement that excludes the Harrison–Zel’dovich–Peebles spectrum by 99.5% CL. The other parameters, including those beyond the minimal set, are also consistent with, and improved from, the five-year results. We find no convincing deviations from the minimal model. The seven-year temperature power spectrum gives a better determination of the third acoustic peak, which results in a better determination of the redshift of the matter-radiation equality epoch. Notable examples of improved parameters are the total mass of neutrinos, � mν < 0.58 eV (95% CL), and the effective number of neutrino species, Neff = 4.34 +0.86 −0.88 (68% CL), which benefit from better determinations of the third peak and H0. The limit on a constant dark energy equation of state parameter from WMAP+BAO+H0, without high-redshift Type Ia supernovae, is w =− 1.10 ± 0.14 (68% CL). We detect the effect of primordial helium on the temperature power spectrum and provide a new test of big bang nucleosynthesis by measuring Yp = 0.326 ± 0.075 (68% CL). We detect, and show on the map for the first time, the tangential and radial polarization patterns around hot and cold spots of temperature fluctuations, an important test of physical processes at z = 1090 and the dominance of adiabatic scalar fluctuations. The seven-year polarization data have significantly improved: we now detect the temperature–E-mode polarization cross power spectrum at 21σ , compared with 13σ from the five-year data. With the seven-year temperature–B-mode cross power spectrum, the limit on a rotation of the polarization plane due to potential parity-violating effects has improved by 38% to Δα =− 1. 1 ± 1. 4(statistical) ± 1. 5(systematic) (68% CL). We report significant detections of the Sunyaev–Zel’dovich (SZ) effect at the locations of known clusters of galaxies. The measured SZ signal agrees well with the expected signal from the X-ray data on a cluster-by-cluster basis. However, it is a factor of 0.5–0.7 times the predictions from “universal profile” of Arnaud et al., analytical models, and hydrodynamical simulations. We find, for the first time in the SZ effect, a significant difference between the cooling-flow and non-cooling-flow clusters (or relaxed and non-relaxed clusters), which can explain some of the discrepancy. This lower amplitude is consistent with the lower-than-theoretically expected SZ power spectrum recently measured by the South Pole Telescope Collaboration.

Planck 2015 results - XIII. Cosmological parameters

Abstract: This paper presents cosmological results based on full-mission Planck observations of temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation. Our results are in very good agreement with the 2013 analysis of the Planck nominal-mission temperature data, but with increased precision. The temperature and polarization power spectra are consistent with the standard spatially-flat 6-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations (denoted “base ΛCDM” in this paper). From the Planck temperature data combined with Planck lensing, for this cosmology we find a Hubble constant, H0 = (67.8 ± 0.9) km s-1Mpc-1, a matter density parameter Ωm = 0.308 ± 0.012, and a tilted scalar spectral index with ns = 0.968 ± 0.006, consistent with the 2013 analysis. Note that in this abstract we quote 68% confidence limits on measured parameters and 95% upper limits on other parameters. We present the first results of polarization measurements with the Low Frequency Instrument at large angular scales. Combined with the Planck temperature and lensing data, these measurements give a reionization optical depth of τ = 0.066 ± 0.016, corresponding to a reionization redshift of . These results are consistent with those from WMAP polarization measurements cleaned for dust emission using 353-GHz polarization maps from the High Frequency Instrument. We find no evidence for any departure from base ΛCDM in the neutrino sector of the theory; for example, combining Planck observations with other astrophysical data we find Neff = 3.15 ± 0.23 for the effective number of relativistic degrees of freedom, consistent with the value Neff = 3.046 of the Standard Model of particle physics. The sum of neutrino masses is constrained to ∑ mν < 0.23 eV. The spatial curvature of our Universe is found to be very close to zero, with | ΩK | < 0.005. Adding a tensor component as a single-parameter extension to base ΛCDM we find an upper limit on the tensor-to-scalar ratio of r0.002< 0.11, consistent with the Planck 2013 results and consistent with the B-mode polarization constraints from a joint analysis of BICEP2, Keck Array, and Planck (BKP) data. Adding the BKP B-mode data to our analysis leads to a tighter constraint of r0.002 < 0.09 and disfavours inflationarymodels with a V(φ) ∝ φ2 potential. The addition of Planck polarization data leads to strong constraints on deviations from a purely adiabatic spectrum of fluctuations. We find no evidence for any contribution from isocurvature perturbations or from cosmic defects. Combining Planck data with other astrophysical data, including Type Ia supernovae, the equation of state of dark energy is constrained to w = −1.006 ± 0.045, consistent with the expected value for a cosmological constant. The standard big bang nucleosynthesis predictions for the helium and deuterium abundances for the best-fit Planck base ΛCDM cosmology are in excellent agreement with observations. We also constraints on annihilating dark matter and on possible deviations from the standard recombination history. In neither case do we find no evidence for new physics. The Planck results for base ΛCDM are in good agreement with baryon acoustic oscillation data and with the JLA sample of Type Ia supernovae. However, as in the 2013 analysis, the amplitude of the fluctuation spectrum is found to be higher than inferred from some analyses of rich cluster counts and weak gravitational lensing. We show that these tensions cannot easily be resolved with simple modifications of the base ΛCDM cosmology. Apart from these tensions, the base ΛCDM cosmology provides an excellent description of the Planck CMB observations and many other astrophysical data sets.

First year Wilkinson Microwave Anisotropy Probe (WMAP) observations: Determination of cosmological parameters

Abstract: WMAP precision data enable accurate testing of cosmological models. We find that the emerging standard model of cosmology, a flat � -dominated universe seeded by a nearly scale-invariant adiabatic Gaussian fluctuations, fits the WMAP data. For the WMAP data only, the best-fit parameters are h ¼ 0:72 � 0:05, � bh 2 ¼ 0:024 � 0:001, � mh 2 ¼ 0:14 � 0:02, � ¼ 0:166 þ0:076 � 0:071 , ns ¼ 0:99 � 0:04, and � 8 ¼ 0:9 � 0:1. With parameters fixed only by WMAP data, we can fit finer scale cosmic microwave background (CMB) measure- ments and measurements of large-scale structure (galaxy surveys and the Lyforest). This simple model is also consistent with a host of other astronomical measurements: its inferred age of the universe is consistent with stellar ages, the baryon/photon ratio is consistent with measurements of the (D/H) ratio, and the inferred Hubble constant is consistent with local observations of the expansion rate. We then fit the model parameters to a combination of WMAP data with other finer scale CMB experiments (ACBAR and CBI), 2dFGRS measurements, and Lyforest data to find the model's best-fit cosmological parameters: h ¼ 0:71 þ0:04 � 0:03 , � bh 2 ¼ 0:0224 � 0:0009, � mh 2 ¼ 0:135 þ0:008 � 0:009 , � ¼ 0:17 � 0:06, ns(0.05 Mpc � 1 )=0 :93 � 0:03, and � 8 ¼ 0:84 � 0:04. WMAP's best determination of � ¼ 0:17 � 0:04 arises directly from the temperature- polarization (TE) data and not from this model fit, but they are consistent. These parameters imply that the age of the universe is 13:7 � 0:2 Gyr. With the Lyforest data, the model favors but does not require a slowly varying spectral index. The significance of this running index is sensitive to the uncertainties in the Ly� forest. By combining WMAP data with other astronomical data, we constrain the geometry of the universe, � tot ¼ 1:02 � 0:02, and the equation of state of the dark energy, w < � 0:78 (95% confidence limit assuming w �� 1). The combination of WMAP and 2dFGRS data constrains the energy density in stable neutrinos: � � h 2 < 0:0072 (95% confidence limit). For three degenerate neutrino species, this limit implies that their mass is less than 0.23 eV (95% confidence limit). The WMAP detection of early reionization rules out warm dark matter. Subject headings: cosmic microwave background — cosmological parameters — cosmology: observations — early universe On-line material: color figure