Browsing by Subject "sky"
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Item Cosmic Microwave Background-Weak Lensing Correlation: Analytical and Numerical Study of Nonlinearity and Implications for Dark Energy(2008-04) Nishizawa, Atushi J.; Komatsu, Eiichiro; Yoshida, Naoki; Takahashi, Ryuichi; Sugiyama, Naoshi; Komatsu, EiichiroEvolution of density fluctuations yields secondary anisotropies in the cosmic microwave background ( CMB), which are correlated with the same density fluctuations that can be measured by weak lensing (WL) surveys. We study the CMB-WL correlation induced by the integrated Sachs-Wolfe (ISW) effect and its nonlinear extension, the Rees-Sciama (RS) effect, using analytical models as well as N-body simulations. We show that an analytical model based on the time derivative of matter power spectrum agrees with simulations. All-sky cosmic-variance-limited CMB and WL surveys allow us to measure the correlation from the nonlinear RS effect with high significance (50 sigma) for l(max) = 10(4) whereas forthcoming missions such as Planck and LSST are expected to yield 4 l p 10 1.5 sigma detections, on the assumption of that the point-source contributions are negligible. We find that the CMB-WL correlation has a characteristic scale which is sensitive to the nature of dark energy.Item Five-Year Wilkinson Microwave Anisotropy Probe Observations: Galactic Foreground Emission(2009-02) Gold, B.; Bennett, C. L.; Hill, R. S.; Hinshaw, G.; Odegard, N.; Page, L.; Spergel, D. N.; Weiland, J. L.; Dunkley, J.; Halpern, M.; Jarosik, N.; Kogut, A.; Komatsu, Eiichiro; Larson, D.; Meyer, S. S.; Nolta, M. R.; Wollack, E.; Wright, E. L.; Komatsu, EiichiroWe present a new estimate of foreground emission in the Wilkinson Microwave Anisotropy Probe (WMAP) data, using a Markov chain Monte Carlo method. The new technique delivers maps of each foreground component for a variety of foreground models with estimates of the uncertainty of each foreground component, and it provides an overall goodness-of-fit estimate. The resulting foreground maps are in broad agreement with those from previous techniques used both within the collaboration and by other authors. We find that for WMAP data, a simple model with power-law synchrotron, free-free, and thermal dust components fits 90% of the sky with a reduced chi(2)(v) of 1.14. However, the model does not work well inside the Galactic plane. The addition of either synchrotron steepening or a modified spinning dust model improves the fit. This component may account for up to 14% of the total flux at the Ka band (33 GHz). We find no evidence for foreground contamination of the cosmic microwave background temperature map in the 85% of the sky used for cosmological analysis.Item The Jet-Driven Outflow In The Radio Galaxy SDSS J1517+3353: Implications For Double-Peaked Narrow-Line Active Galactic Nucleus(2010-06) Rosario, D. J.; Shields, Gregory A.; Taylor, G. B.; Salviander, Sarah; Smith, K. L.; Shields, Gregory A.; Salviander, Sarah; Smith, K. L.We report on the study of an intriguing active galaxy that was selected as a potential multiple supermassive black hole merger in the early-type host SDSS J151709.20+335324.7 (z = 0.135) from a complete search for double-peaked [O III] lines from the SDSS spectroscopic quasi-stellar object (QSO) database. Ground-based SDSS imaging reveals two blue structures on either side of the photometric center of the host galaxy, separated from each other by about 5.7 kpc. From a combination of SDSS fiber and Keck/HIRES long-slit spectroscopy, it is demonstrated that, in addition to these two features, a third distinct structure surrounds the nucleus of the host galaxy. All three structures exhibit highly ionized line emission with line ratios characteristic of Seyfert II active galactic nuclei. The analysis of spatially resolved emission-line profiles from the HIRES spectrum reveal three distinct kinematic subcomponents, one at rest and the other two moving at -350 km s(-1) and 500 km s(-1) with respect to the systemic velocity of the host galaxy. A comparison of imaging and spectral data confirm a strong association between the kinematic components and the spatial knots, which implies a highly disturbed and complex active region in this object. A comparative analysis of the broadband positions, colors, kinematics, and spectral properties of the knots in this system lead to two plausible explanations: (1) a multiple active galactic nucleus (AGN) produced due to a massive dry merger, or (2) a very powerful radio jet-driven outflow. Subsequent VLA radio imaging reveals a clear jet aligned with the emission-line gas, confirming the latter explanation. We use the broadband radio measurements to examine the impact of the jet on the interstellar medium of the host galaxy, and find that the energy in the radio lobes can heat a significant fraction of the gas to the virial temperature. Finally, we discuss tests that may help future surveys distinguish between jet-driven kinematics and true black-hole binaries. J1517+3353 is a remarkable laboratory for AGN feedback and warrants deeper follow-up study. In the Appendix, we present high-resolution radio imaging of a second AGN with double-peaked [O III] lines, SDSS J112939.78+605742.6, which shows a sub-arcsecond radio jet. If the double-peaked nature of the narrow lines in radio-loud AGNs are generally due to radio jet interactions, we suggest that extended radio structure should be expected in most of such systems.Item Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Galactic foreground Emission(2011-02) Gold, B.; Odegard, N.; Weiland, J. L.; Hill, R. S.; Kogut, A.; Bennett, C. L.; Hinshaw, G.; Chen, X.; Dunkley, J.; Halpern, M.; Jarosik, N.; Komatsu, Eiichiro; Larson, D.; Limon, M.; Meyer, S. S.; Nolta, M. R.; Page, L.; Smith, K. M.; Spergel, D. N.; Tucker, G. S.; Wollack, E.; Wright, E. L.; Komatsu, EiichiroWe present updated estimates of Galactic foreground emission using seven years of WMAP data. Using the power spectrum of differences between multi-frequency template-cleaned maps, we find no evidence for foreground contamination outside of the updated (KQ85y7) foreground mask. We place a 15 mu K upper bound on rms foreground contamination in the cleaned maps used for cosmological analysis. Further, the cleaning process requires only three power-law foregrounds outside of the mask. We find no evidence for polarized foregrounds beyond those from soft (steep-spectrum) synchrotron and thermal dust emission; in particular we find no indication in the polarization data of an extra "haze" of hard synchrotron emission from energetic electrons near the Galactic center. We provide an updated map of the cosmic microwave background (CMB) using the internal linear combination method, updated foreground masks, and updates to point source catalogs using two different techniques. With additional years of data, we now detect 471 point sources using a five-band technique and 417 sources using a three-band CMB-free technique. In total there are 62 newly detected point sources, a 12% increase over the five-year release. Also new are tests of the Markov chain Monte Carlo foreground fitting procedure against systematics in the time-stream data, and tests against the observed beam asymmetry. Within a few degrees of the Galactic plane, the behavior in total intensity of low-frequency foregrounds is complicated and not completely understood. WMAP data show a rapidly steepening spectrum from 20 to 40 GHz, which may be due to emission from spinning dust grains, steepening synchrotron, or other effects. Comparisons are made to a 1 deg 408 MHz map (Haslam et al.) and the 11 deg ARCADE 2 data (Singal et al.). We find that spinning dust or steepening synchrotron models fit the combination of WMAP and 408 MHz data equally well. ARCADE data appear inconsistent with the steepening synchrotron model and consistent with the spinning dust model, though some discrepancies remain regarding the relative strength of spinning dust emission. More high-resolution data in the 10-40 GHz range would shed much light on these issues.Item Simple Foreground Cleaning Algorithm For Detecting Primordial B-Mode Polarization Of The Cosmic Microwave Background(2011-08) Katayama, Nobuhiko; Komatsu, Eiichiro; Komatsu, EiichiroWe reconsider the pixel-based, "template" polarized foreground removal method within the context of a next-generation, low-noise, low-resolution (0 degrees.5 FWHM) space-borne experiment measuring the cosmological B-mode polarization signal in the cosmic microwave background (CMB). This method was first applied to polarized data by the Wilkinson Microwave Anisotropy Probe (WMAP) team and further studied by Efstathiou et al. We need at least three frequency channels: one is used for extracting the CMB signal, whereas the other two are used to estimate the spatial distribution of the polarized dust and synchrotron emission. No extra data from non-CMB experiments or models are used. We extract the tensor-to-scalar ratio (r) from simulated sky maps outside the standard polarization mask (P06) of WMAP consisting of CMB, noise (2 mu K arcmin), and a foreground model, and find that, even for the simplest three-frequency configuration with 60, 100, and 240 GHz, the residual bias in r is as small as Delta r approximate to 0.002. This bias is dominated by the residual synchrotron emission due to spatial variations of the synchrotron spectral index. With an extended mask with f(sky) = 0.5, the bias is reduced further down to <0.001.