Now showing items 555-574 of 845

    • A Parametric Down-Conversion Source for Two-Photon Absorption Experiments 

      Pittman, T.B.; Franson, J.D.; Pittman, T.B.; Hendrickson, S. M.; Franson, J.D. (OSA Publishing, 2008-07)
      We describe a Parametric Down-Conversion source based on a low-power (< 1mW), narrowband (<1 MHz) fiber-coupled pump laser. The source is designed for two-photon absorption experiments related to quantum Zeno gates.
    • Pareidolic Dark Matter (PaDaM) 

      Mirabal, N. (2013-03-28)
      A pareidolic conjecture for the Fermi Large Area Telescope.
    • Parsec-Scale Blazar Monitoring: Flux and Polarization Variability 

      Homan, Daniel C.; Ojha, Roopesh; Wardle, John F. C.; Roberts, David H.; Aller, Margo F.; Aller, Hugh D.; Hughes, Philip A. (IOP, 2002-03-20)
      We present analysis of the flux density and polarization variability of parsec-scale radio jets from a dual-frequency, six-epoch, VLBA polarization experiment monitoring 12 blazars. The observations were made at 15 and 22 ...
    • Parsec-Scale Blazar Monitoring: Proper Motions 

      Homan, Daniel C.; Ojha, Roopesh; Wardle, John F. C.; Roberts, David H.; Aller, Margo F.; Aller, Hugh D.; Philip A. Hughes (IOP, 2001-03-10)
      We present proper motions obtained from a dual-frequency, six-epoch, VLBA polarization experiment monitoring a sample of 12 blazars. The observations were made at 15 and 22 GHz at bimonthly intervals over 1996. A total of ...
    • Parsec-Scale Blazar Monitoring: The Data 

      Ojha, Roopesh; Homan, Daniel C.; Roberts, David H.; Wardle, John F. C.; Aller, Margo F.; Aller, Hugh D.; Hughes, Philip A. (IOP, 2004-01-01)
      We present the images and modeling data obtained from a dual frequency, six-epoch, VLBA polarization experiment monitoring a sample of 12 blazars. The observations were made at 15 and 22 GHz at evenly spaced, bimonthly ...
    • Parsec-scale structure of quasars: dawn of the golden age? 

      Ojha, Roopesh (Roopesh Ojha, Parsec-scale structure of quasars: dawn of the golden age?, https://arxiv.org/abs/1310.0875, 2013-10-03)
      Half a century after their discovery, the study of quasars remains one of the most fascinating intellectual challenges in astronomy. Quasars are laboratories for everything from relativity to magnetohydrodynamics and are ...
    • Periodic single-photon source and quantum memory 

      Pittman, Todd B.; Fitch, Michael J.; Jacobs, Bryan C.; Franson, Jason M. (SPIE, 2004-02-03)
      Although there has been tremendous progress in the development of true “on-demand” single-photon sources, periodic or “pseudodemand” single-photon sources can be a sufficient resource for many optical quantum information ...
    • A pervasive role for biomass burning in tropical high ozone/low water structures 

      Anderson, Daniel C.; Nicely, Julie M.; Salawitch, Ross J.; Canty, Timothy P.; Dickerson, Russell R.; Hanisco, Thomas F.; Wolfe, Glenn M.; Apel, Eric C.; Atlas, Elliot; Bannan, Thomas; Bauguitte, Stephane; Blake, Nicola J.; Bresch, James F.; Campos, Teresa L.; Carpenter, Lucy J.; Cohen, Mark D.; Evans, Matthew; Fernandez, Rafael P.; Kahn, Brian H.; Kinnison, Douglas E.; Hall, Samuel R.; Harris, Neil R.P.; Hornbrook, Rebecca S.; Lamarque, Jean-Francois; Breton, Michael Le; Lee, James D.; Percival, Carl; Pfister, Leonhard; Pierce, R. Bradley; Riemer, Daniel D.; Saiz-Lopez, Alfonso; Stunder, Barbara J.B.; Thompson, Anne M.; Ullmann, Kirk; Vaughan, Adam; Weinheimer, Andrew J. (Nature Research, 2016-01-13)
      Air parcels with mixing ratios of high O₃ and low H₂O (HOLW) are common features in the tropical western Pacific (TWP) mid-troposphere (300–700 hPa). Here, using data collected during aircraft sampling of the TWP in winter ...
    • Photochemical modeling of glyoxal at a rural site: observations and analysis from BEARPEX 2007 

      Huisman, A. J.; Hottle, J. R.; Galloway, M. M.; DiGangi, J. P.; Coens, K. L.; Choi, W.; Faloona, I. C.; Gilman, J. B.; Kuster, W. C.; Gouw, J. de; Bouvier-Brown, N. C.; Goldstein, A. H.; LaFranchi, B. W.; Cohen, R. C.; Wolfe, G. M.; Thornton, J. A.; Docherty, K. S.; Farmer, D. K.; Cubison, M. J.; Jimenez, J. L.; Mao, J.; Brune, W. H.; Keutsch, F. N. (Copernicus Publications, 2011-09-01)
      We present roughly one month of high time-resolution, direct, in situ measurements of gas-phase glyoxal acquired during the BEARPEX 2007 field campaign. The research site, located on a ponderosa pine plantation in the ...
    • PHOTOMETRIC OBSERVATIONS OF SELECTED, OPTICALLY BRIGHT QUASARS FOR SPACE INTERFEROMETRY MISSION AND OTHER FUTURE CELESTIAL REFERENCE FRAMES 

      Ojha, Roopesh; Zacharias, Norbert; Hennessy, Gregory S.; Gaume, Ralph A.; Johnston, Kenneth J. (IOP, 2009-07-31)
      Photometric observations of 235 extragalactic objects that are potential targets for the Space Interferometry Mission (SIM) are presented. Mean B, V, R, I magnitudes at the 5% level are obtained at 1-4 epochs between 2005 ...
    • Photon-number resolution using time-multiplexed single-photon detectors 

      Fitch, M. J.; Jacobs, B. C.; Pittman, T.B.; Franson, J.D. (American Physical Society (APS), 2003-10-10)
      Photon-number-resolving detectors are needed for a variety of applications including linear-optics quantum computing. Here we describe the use of time-multiplexing techniques that allow ordinary single-photon detectors, ...
    • Photon-number-resolving detection using time-multiplexing 

      Achilles, Daryl; Silberhorn, Christine; Sliwa, Cezary; Banaszek, Konrad; Walmsley, Ian A.; Fitch, Michael J.; Jacobs, Bryan C.; Pittman, Todd B.; Franson, James D. (Taylor & Francis, 2009-07-03)
      Detectors that can resolve photon number are needed in many quantum information technologies. In order to be useful in quantum information processing, such detectors should be simple, easy to use, and be scalable to resolve ...
    • physics, emission mechanisms, and challenges of Kiloparsec-scale Jets: 

      Perlman, Eric S.; Meyer, Eileen; Eilek, Jean; Tchekhovskoy, Sasha; Nyland, Kristina; Agudo, Ivan; Baum, Stefi; Hardcastle, Martin; Kadler, Matthias; Labiano, Alvaro; Marshall, Herman; ODea, Christopher; Worrall, Diana (2019-03-08)
      Jets are a ubiquitous part of the accretion process, created in AGN, by a coupling between the magnetic field near the central black hole and inflowing material. We point out what advances can be achieved by new technologies, ...
    • PKS 1954−388: RadioAstron Detection on 80,000 km Baselines and Multiwavelength Observations 

      Edwards, P.G.; Kovalev, Y.Y.; Ojha, R.; An, H.; Bignall, H.; Carpenter, B.; Hovatta, T.; Stevens, J.; Voytsik, P.; Andrianov, A.S.; Dutka, M.; Hase, H.; Horiuchi, S.; Jauncey, D.L.; Kadler, M.; Lisakov, M.; Lovell, J.E.J.; McCallum, J.; Muller, C.; Phillips, C.; Plotz, C.; Quick, J.; Reynolds, C.; Schulz, R.; Sokolovsky, K.V.; Tzioumis, A.K.; Zuga, V. (Astronomical Society of Australia (PASA), 2017-05-05)
      We present results from a multiwavelength study of the blazar PKS 1954−388 at radio, UV, X-ray, and gamma-ray energies. A RadioAstron observation at 1.66 GHz in June 2012 resulted in the detection of interferometric fringes ...
    • PKS 2123−463: a confirmed γ-ray blazar at high redshift 

      D'Ammando, F.; Rau, A.; Schady, P.; Finke, J.; Orienti, M.; Greiner, J.; Kann, D. A.; Ojha, R.; Foley, A. R.; Stevens, J.; Blanchard, J. M.; Edwards, P. G.; Kadler, M.; Lovell, J. E. J. (Oxford University Press, 2012-11-21)
      The flat spectrum radio quasar (FSRQ) PKS 2123−463 was associated in the first Fermi-Large Area Telescope (LAT) source catalogue with the γ-ray source 1FGL J2126.1−4603, but when considering the full first two years of ...
    • A planet within the debris disk around the pre-main-sequence star AU Microscopii 

      Barclay, Thomas; et al. (Springer Nature, 2020-06-24)
      AU Microscopii (AU Mic) is the second closest pre-main-sequence star, at a distance of 9.79 parsecs and with an age of 22 million years. AU Mic possesses a relatively rare and spatially resolved edge-on debris disk extending ...
    • The Plankton, Aerosol, Cloud, Ocean Ecosystem Mission: Status, Science, Advances 

      Werdell, P. Jeremy; Behrenfeld, Michael J.; Bontempi, Paula S.; Boss, Emmanuel; Cairns, Brian; Davis, Gary T.; Franz, Bryan A.; Gliese, Ulrik B.; Gorman, Eric T.; Hasekamp, Otto; Knobelspiesse, Kirk D.; Mannino, Antonio; Martins, J. Vanderlei; McClain, Charles R.; Meister, Gerhard; Remer, Lorraine A. (American Meteorological Society, 2019-09-27)
      The Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) mission represents the National Aeronautics and Space Administration’s (NASA) next investment in satellite ocean color and the study of Earth’s ocean–atmosphere system, ...
    • Plasmon-exciton coupling 

      Pelton, Matthew; Sheldon, Matthew; Khurgin, Jacob (De Gruyter, 2019-03-15)
    • A Point-Source Catalog from Swift Observations of Unidentified Fermi Sources 

      Mirabal, N. (2009-08-11)
      We present X-ray point source catalogs obtained from archival Swift observations that have partially or fully covered the 95% confidence error contour of unidentified Fermi sources. In total, 21 out of 37 unidentified Fermi ...
    • POLARIZATION DIAGNOSTICS FOR COOL CORE CLUSTER EMISSION LINES 

      Sparks, W. B.; Pringle, J. E.; Carswell, R. F.; Voit, G. M.; Donahue, M.; Cracraft, M.; Meyer, E. T.; Hough, J. H.; Manset, N. (IOP, 2013-12-12)
      The nature of the interaction between low-excitation gas filaments at ~10⁴ K, seen in optical line emission, and diffuse X-ray emitting coronal gas at ~10⁷ K in the centers of galaxy clusters remains a puzzle. The presence ...