Now showing items 8-27 of 845

    • The Accretion History of AGN: A Newly Defined Population of Cold Quasars 

      Kirkpatrick, Allison; Urry, C. Megan; Brewster, Jason; Cooke, Kevin C.; Estrada, Michael; Glikman, Eilat; Hamblin, Kurt; Ananna, Tonima Tasnim; Carlile, Casey; Coleman, Brandon; Johnson, Jordan; Kartaltepe, Jeyhan S.; LaMassa, Stephanie M.; Marchesi, Stefano; Powell, Meredith; Sanders, Dave; Treister, Ezequiel; Turner, Tracey Jane (2019-08-15)
      Quasars are the most luminous of active galactic nuclei (AGN), and are perhaps responsible for quenching star formation in their hosts. The Stripe 82X catalog covers 31.3 deg² of the Stripe 82 field, of which the 15.6 deg² ...
    • Accuracy and Stability Assessment of the ILRS Stations Over Two Decades 

      Pavlis, Erricos C.; Evans, K.; Kuzmicz-Cieslak, M. (National Aeronautics and Space Administration, 2013-11-11)
      The development of the ITRF depends on the quality of the contributions from the four geometric techniques. With the GGOS requirements for ITRF accuracy and stability becoming exceedingly stringent, ITRS requests that ...
    • Accurate Astrometry of 22 Southern Hemisphere Radio Sources 

      Fey, Alan L.; Ojha, Roopesh; Jauncey, David L.; Johnston, Kenneth J.; Reynolds, John E.; Lovell, James E. J.; Tzioumis, Anastasios K.; Quick, Jonathan F. H.; Nicolson, George D.; Ellingsen, Simon P.; McCulloch, Peter M.; Koyama, Yasuhiro (IOP, 2003-12-03)
      Milliarcsecond-accurate radio positions for 22 southern hemisphere extragalactic sources are reported. These positions are derived from Mark III very long baseline interferometry observations made between 2003 February and ...
    • Active Galactic Nuclei under the scrutiny of CTA 

      Sol, H.; Zech, A.; Boisson, C.; Almeida, U. Barres de; Biteau, J.; Contreras, J.-L.; Giebels, B.; Hassan, T.; Inoue, Y.; Katarzynsk, K.; Krawczynski, H.; Mirabal, N.; Poutanen, J.; Rieger, F.; Totani, T.; Benbow, W.; Cerruti, M.; Errando, M.; Fallon, L.; Pino, E. de Gouveia Dal; Hinton, J.A.; Inoue, S.; Lenain, J.-P.; Neronov, A.; Takahashi, K.; Takami, H.; White, R. (Elsevier, 2012-12-20)
      Active Galactic Nuclei (hereafter AGN) produce powerful outflows which offer excellent conditions for efficient particle acceleration in internal and external shocks, turbulence, and magnetic reconnection events. The jets ...
    • Aegean Sea Level Network: Eastern Mediterranean Altimeter Calibration Network – eMACnet 

      Pavlis, Erricos C.; Evans, K.; Milas, P.; Massinas, B.A.; Paradissis, D. (National Aeronautics and Space Administration, 2009-09-14)
    • THE AFTERGLOWS OF SWIFT-ERA GAMMA-RAY BURSTS. I. COMPARING PRE-SWIFT AND SWIFT-ERA LONG/SOFT (TYPE II) GRB OPTICAL AFTERGLOWS 

      Mirabal, N. (IOP, 2010-08-23)
      We have gathered optical photometry data from the literature on a large sample of Swift-era gamma-ray burst (GRB) afterglows including GRBs up to 2009 September, for a total of 76 GRBs, and present an additional three ...
    • AGN Forecasting 

      Hassan, Tarek; Mirabal, Nestor; Contreras, Jose Luis; the CTA Consortium (POS, 2012-06-20)
      The First Fermi-LAT catalog (1FGL) represents the most complete list of sources in the GeV sky to date. We use the reported 1FGL spectral parameters to extrapolate Fermi AGN spectra to the very-high energy (VHE) range (15 ...
    • AGN TXS 1923+123 

      Carpenter, Bryce; Ojha, Roopesh (The Astronomer's Telegram, 2016-01-01)
    • Airborne measurements of BrO and the sum of HOBr and Br2 over the Tropical West Pacific from 1 to 15 km during the CONvective TRansport of Active Species in the Tropics (CONTRAST) experiment 

      Chen, Dexian; Huey, L. Gregory; Tanner, David J.; Salawitch, Ross J.; Anderson, Daniel C.; Wales, Pamela A.; Pan, Laura L.; Atlas, Elliot L.; Hornbrook, Rebecca S.; Apel, Eric C.; Blake, Nicola J.; Campos, Teresa L.; Donets, Valeria; Flocke, Frank M.; Hall, Samuel R.; Hanisco, Thomas F.; Hills, Alan J.; Honomichl, Shawn B.; Jensen, Jørgen B.; Kaser, Lisa; Montzka, Denise D.; Nicely, Julie M; Reeves, Michael J.; Riemer, Daniel D.; Schauffler, Sue M.; Ullmann, Kirk; Weinheimer, Andrew J.; Wolfe, Glenn M. (AGU Pubication, 2016-10-13)
      A chemical ionization mass spectrometer was used to measure BrO and HOBr + Br₂ over the Tropical West Pacific Ocean within the altitude range of 1 to 15 km, during the CONvective TRansport of Active Species in the Tropics ...
    • Airborne measurements of the atmospheric emissions from a fuel ethanol refinery 

      Gouw, J. A. de; McKeen, S. A.; Aikin, K. C.; Brock, C. A.; Brown, S. S.; Gilman, J. B.; Graus, M.; Hanisco, T.; Holloway, J. S.; Kaiser, J.; Keutsch, F. N.; Lerner, B.M.; Liao, J.; Markovic, M. Z.; Middlebrook, A. M.; Min, K.-E.; Neuman, J. A.; Nowak, J. B.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Trainer, M.; Veres, P. R.; Warneke, C.; Welti, A.; Wolfe, G. M. (AGU Pubication, 2015-04-08)
      Ethanol made from corn now constitutes approximately 10% of the fuel used in gasoline vehicles in the U.S. The ethanol is produced in over 200 fuel ethanol refineries across the nation. We report airborne measurements ...
    • Airborne measurements of western U.S. wildfire emissions: Comparison with prescribed burning and air quality implications 

      Liu, Xiaoxi; Huey, L. Gregory; Yokelson, Robert J.; Selimovic, Vanessa; Simpson, Isobel J.; Müller, Markus; Jimenez, Jose L.; Campuzano‐Jost, Pedro; Beyersdorf, Andreas J.; Blake, Donald R.; Zachary, Butterfield; Choi, Yonghoon; Crounse, John D.; Day, Douglas A.; Diskin, Glenn S.; Dubey, Manvendra K.; Edward, Fortner; Hanisco, Thomas F.; Hu, Weiwei; King, Laura E.; Kleinman, Lawrence; Meinardi, Simone; Mikoviny, Tomas; Onasch, Timothy B.; Palm, Brett B.; Peischl, Jeff; Pollack, Ilana B.; Ryerson, Thomas B.; Sachse, Glen W.; Sedlacek, Arthur J.; Shilling, John E.; Springston, Stephen; St. Clair, Jason M.; Tanner, David J.; Teng, Alexander P.; Wennberg, Paul O.; Wisthaler, Armin; Wolfe, Glenn M. (AGU Pubication, 2017-06-14)
      Wildfires emit significant amounts of pollutants that degrade air quality. Plumes from three wildfires in the western U.S. were measured from aircraft during the Studies of Emissions and Atmospheric Composition, Clouds and ...
    • AIRS L1c Frequency Calibration 

      UMBC Atmospheric Spectroscopy Lab (ASL) (2019-11-03)
      This document summarizes the observed frequency drifts in the AIRS L1b radiances and then describes how they are corrected in the AIRS L1c product that should be available at the NASA Goddard DISC in early 2010. The ...
    • AIRS version 6.6 and version 7 level-1C products 

      Manning, Evan M.; Strow, L. Larrabee; Aumann, Hartmut H. (SPIE, 2019-09-09)
      The Atmospheric Infrared Sounder (AIRS) introduces new Level-1C (L1C) products. AIRS Version 6.6 L1C processing addresses data quality and sampling issues as well as spectral drift, making a clean, easy to use product. ...
    • THE ALGOL TRIPLE SYSTEM SPATIALLY RESOLVED AT OPTICAL WAVELENGTHS 

      Zavala, R. T.; Hummel, C. A.; Boboltz, D. A.; Ojha, R.; Shaffer, D. B.; Tycner, C.; Richards, M. T.; Hutter, D. J. (IOP, 2010-04-30)
      Interacting binaries typically have separations in the milliarcsecond regime, and hence it has been challenging to resolve them at any wavelength. However, recent advances in optical interferometry have improved our ability ...
    • ALL-OPTICAL NONLINEAR ACTIVATION FUNCTION FOR PHOTONIC NEURAL NETWORKS 

      Miscuglio, Mario; Mehrabian, Armin; Hu, Zibo; Azzam, Shaimaa I.; George, Jonathan; Kildishev, Alexander V.; Pelton, Matthew; Sorger, Volker J. (Optical Society of America, 2018)
      With the recent successes of neural networks (NN) to perform machine-learning tasks, photonic-based NN designs may enable high throughput and low power neuromorphic compute paradigms since they bypass the parasitic charging ...
    • All-Optical Switching Demonstration using Two-Photon Absorption and the Classical Zeno Effect 

      Hendrickson, S. M.; Weiler, C. N.; Camacho, R.M.; Rakich, P. T.; Young, A. I.; Shaw, M. J.; Pittman, T. B.; Franson, J. D.; Jacobs, B. C. (2018-10-31)
      Low-contrast all-optical Zeno switching has been demonstrated in a Si3N4 microdisk resonator coupled to a hot atomic vapor. The device is based on the suppression of the field build-up within a microcavity due to non-degenerate ...
    • All-optical-switching demonstration using two-photon absorption and the Zeno effect 

      Hendrickson, S. M.; Weiler, C. N.; Camacho, R. M.; Rakich, P. T.; Young, A. I.; Shaw, M. J.; Pittman, T.B.; Franson, J.D.; Jacobs, B. C. (American Physical Society (APS), 2013-02-07)
      Low-contrast all-optical Zeno switching has been demonstrated in a Si₃N₄ microdisk resonator coupled to warm atomic vapor. The device is based on the suppression of the resonant microcavity field buildup due to nondegenerate ...
    • All-optical-switching demonstration using two-photon absorption and the Zeno effect 

      Hickman, G. T.; Franson, J.D.; Pittman, T.B. (OSA Publishing, 2016)
      Metastable states of noble gas atoms are typically produced by electrical discharge techniques or “all-optical” excitation methods. Here we combine electrical discharges with optical pumping to demonstrate “optically ...
    • All-sky Medium Energy Gamma-ray Observatory: Exploring the Extreme Multimessenger Universe 

      McEnery, Julie E.; Ojha, R.; Georganopoulos, Markos; Meyer, Eileen (2019-07-10)
      The All-sky Medium Energy Gamma-ray Observatory (AMEGO) is a probe class mission concept that will provide essential contributions to multimessenger astrophysics in the late 2020s and beyond. AMEGO combines high sensitivity ...
    • An alternative procedure for the estimation of the altimeter bias for the Jason-1 satellite using the dedicated calibration site at Gavdos 

      Mertikas, Stelios P.; Papadopoulos, Ath.; Pavlis, Erricos C. (SPIE, 2008-10-13)
      The dedicated calibration site for satellite radar altimeters in Gavdos has been operational since 2004. The small island of Gavdos is located along a repeating ground track of Jason satellites (crossover point No.109 ...