Now showing items 407-426 of 841

    • A machine learning examination of hydroxyl radical differences among model simulations for CCMI-1 

      Nicely, Julie M.; Duncan, Bryan N.; Hanisco, Thomas F.; Wolfe, Glenn M.; Salawitch, Ross J.; Deushi, Makoto; Haslerud, Amund S.; Jöckel, Patrick; Josse, Béatrice; Kinnison, Douglas E.; Klekociuk, Andrew; Manyin, Michael E.; Marécal, Virginie; Morgenstern, Olaf; Murray, Lee T.; Myhre, Gunnar; Oman, Luke D.; Pitari, Giovanni; Pozzer, Andrea; Quaglia, Ilaria; Revell, Laura E.; Rozanov, Eugene; Stenke, Andrea; Stone, Kane; Strahan, Susan; Tilmes, Simone; Tost, Holger; Westervelt, Daniel M.; Zeng, Guang (EGU Publications, 2020-02-05)
      The hydroxyl radical (OH) plays critical roles within the troposphere, such as determining the lifetime of methane (CH₄), yet is challenging to model due to its fast cycling and dependence on a multitude of sources and ...
    • Machine-learning classifiers for Fermi AGN 

      Hassan, T.; Mirabal, N.; Contreras, J. L.; Oya, I. (AIP publishing, 2012-12-11)
      The Fermi Gamma-ray Space Telescope is generating the most detailed map of the gamma-ray sky. While tremendously successful, approximately 25% of all associated Fermi extragalactic sources in the Second Fermi LAT Catalog ...
    • MAGIC observation of the unassociated Fermi-LAT object 2FGL J1410. 4+ 7411 

      BARRIO, J.A.; Doro, M.; LOZANO, I.; Mirabal, N.; Paiano, S; Satalecka, K.; MAGIC Collaboration (NASA, 2013)
    • Mapping hydroxyl variability throughout the global remote troposphere via synthesis of airborne and satellite formaldehyde observations 

      Wolfe, Glenn M.; Nicely, Julie M.; St. Clair, Jason M.; Hanisco, Thomas F.; Liao, Jin; Oman, Luke D.; Brune, William B.; Miller, David; Thames, Alexander; Abad, Gonzalo González; Ryerson, Thomas B.; Thompson, Chelsea R.; Peischl, Jeff; McKain, Kathryn; Sweeney, Colm; Wennberg, Paul O.; Kim, Michelle; Crounse, John D.; Hall, Samuel R.; Ullmann, Kirk; Diskin, Glenn; Bui, Paul; Chang, Cecilia; Dean-Day, Jonathan (PNAS, 2019-05-20)
      The hydroxyl radical (OH) fuels tropospheric ozone production and governs the lifetime of methane and many other gases. Existing methods to quantify global OH are limited to annual and global-to-hemispheric averages. Finer ...
    • The MASIV Survey – IV. Relationship between intra-day scintillation and intrinsic variability of radio AGNs 

      Koay, J Y; Macquart, J-P; Jauncey, D L; Pursimo, T; Giroletti, M; Bignall, H E; Lovell, J. E. J.; Rickett, B. J.; Kedziora-Chudczer, L.; Ojha, R.; Reynolds, C. (Oxford University Press, 2017-11-27)
      We investigate the relationship between 5 GHz interstellar scintillation (ISS) and 15 GHz intrinsic variability of compact, radio-selected active galactic nuclei (AGNs) drawn from the Microarcsecond Scintillation-Induced ...
    • MASIV:The Microarcsecond Scintillation-Induced Variability Survey 

      Lovell, J.E.J.; Jauncey, D.L.; Senkbeil, C.; Shabala, S.; Bignall, H.E.; Pursimo, T.; Ojha, R.; Macquart, J.-P.; Rickett, B.J.; Dutka, M.; Kedziora-Chudczer, L. (Astronomical Society of the Pacific, 2007-01-21)
      We are undertaking a large-scale 5 GHz VLA survey of the northern sky to search for rapid intra-day variability (IDV). Over four observing epochs we found that 56% of the sources showed variability on timescales of hours ...
    • Mass outflow of the X-ray emission line gas in NGC 4151 

      Kraemer, S. B.; Turner, T. J.; Couto, J. D.; Crenshaw, D. M.; Schmitt, H. R.; Revalski, M.; Fischer, T. C. (Oxford University Press, 2020-02-14)
      We have analysed Chandra/High Energy Transmission Gratings spectra of the X-ray emission line gas in the Seyfert galaxy NGC 4151. The zeroth-order spectral images show extended H- and He-like O and Ne, up to a distance r ...
    • Maximizing optical production of metastable xenon 

      Lamsal, H.P.; Franson, J.D.; Pittman, T.B. (2020-06-05)
      The wide range of applications using metastable noble gas atoms has led to a number of different approaches for producing large metastable state densities. Here we investigate a recently proposed hybrid approach that ...
    • An MCM modeling study of nitryl chloride (ClNO2) impacts on oxidation, ozone production and nitrogen oxide partitioning in polluted continental outflow 

      Riedel, T. P.; Wolfe, G. M.; Danas, K. T.; Gilman, J. B.; Kuster, W. C.; Bon, D. M.; Vlasenko, A.; Li, S. M.; Williams, E. J.; Lerner, B.M.; Veres, P. R.; Roberts, J. M.; Holloway, J.S.; Lefer, B.; Brown, S. S.; Thornton, J. A. (Copernicus, 2014-04-16)
      Nitryl chloride (ClNO₂) is produced at night by reactions of dinitrogen pentoxide (N₂O₅) on chloride containing surfaces. ClNO₂ is photolyzed during the morning hours after sunrise to liberate highly reactive chlorine atoms ...
    • Measuring the relativistic perigee advance with Satellite Laser Ranging 

      Iorio, Lorenzo; Ciufolini, Ignazio; Pavlis, Erricos C. (IOP, 2002-07-30)
      The pericentric advance of a test body by a central mass is one of the classical tests of general relativity. Today, this effect is measured with radar ranging by the perihelion shift of Mercury and other planets in the ...
    • The Merger in Abell 576: A Line-of-Sight Bullet Cluster? 

      Dupke, Renato A.; Mirabal, Nestor; Bregman, Joel N.; Evrard, August E. (IOP, 2007-05-22)
      Using a combination of Chandra and XMM-Newton observations, we confirmed the presence of a significant velocity gradient along the northeast-southwest direction in the intracluster gas of the cluster Abell 576. The results ...
    • The MHz-peaked radio spectrum of the unusual γ-ray source PMN J1603–4904 

      Müller, C.; Burd, P. R.; Schulz, R.; Coppejans, R.; Falcke, H.; Intema, H.; Kadler, M.; Krauß, F.; Ojha, R. (EDP sciences, 2016-09-27)
      Context. The majority of bright extragalactic γ-ray sources are blazars. Only a few radio galaxies have been detected by Fermi/LAT. Recently, the GHz-peaked spectrum source PKS 1718–649 was confirmed to be γ-ray bright, ...
    • The Micro-Arcsecond Scintillation-Induced Variability (MASIV) Survey. II. The First Four Epochs 

      Lovell, J. E. J.; Rickett, B. J.; Macquart, J-P; Jauncey, D. L.; Bignall, H. E.; Kedziora-Chudczer, L.; Ojha, R.; Pursimo, T.; Dutka, M.; Senkbeil, C.; Shabala, S. (IOP, 2008-12-10)
      We report on the variability of 443 flat-spectrum, compact radio sources monitored using the VLA for 3 days in four epochs at ~4 month intervals at 5 GHz as part of the Micro-Arcsecond Scintillation-Induced Variability ...
    • The Micro-Arcsecond Scintillation-Induced Variability (MASIV) Survey. III. Optical Identifications and New Redshifts 

      Pursimo, Tapio; Ojha, Roopesh; Jauncey, David L.; Rickett, Barney J.; Dutka, Michael S.; Koay, Jun Yi; Lovell, James E. J.; Bignall, Hayley E.; Kedziora-Chudczer, Lucyna; Macquart, Jean-Pierre (IOP, 2013-03-20)
      Intraday variability (IDV) of the radio emission from active galactic nuclei is now known to be predominantly due to interstellar scintillation (ISS). The MASIV (The Micro-Arcsecond Scintillation-Induced Variability) survey ...
    • Microarcsecond Resolution with Interstellar Scintillation 

      Jauncey, David L.; Bignall, Hayley E.; Kedziora-Chudczer, Lucyna; Koay, Jun Yi; Lovell, James E. J.; Macquart, Jean-Pierre; Ojha, Roopesh; Pursimo, Tapio; Reynolds, Cormac; Rickett, Barney (Proceedings of Science, 2012-04-17)
      The rapid, intra- and inter-day variability now seen at cm wavelengths in many compact, flatspectrum radio sources, was discovered almost thirty years ago based on accurate flux density measurements made with the Effelsberg ...
    • Microarcsecond scintillation-induced variability (MASIV) survey of the northern sky 

      Lovell, J.E.J.; Senkbeil, C.; Shabala, S.; Bignall, H.E.; Pursimo, T.; Ojha, R.; Dutka, M.; Macquart, J.-P.; Rickett, B.J.; Kedziora-Chudczer, L. (Taylor & Francis Online, 2007-12-13)
      We present the results of a large-scale 5-GHz Very Large Array (VLA) survey of the northern sky searching for sources that exhibit intraday variability (IDV). The observations were made over four epochs, each of 3 days in ...
    • The MicroArcsecond Scintillation-Induced Variability (MASIV) Survey: Detection of Angular Broadening at High Redshift? 

      Pursimo, T.; Ojha, R.; Jauncey, D.; Lovell, J.; Dutka, M.; Bignall, H.; Macquart, J.-P.; Rickett, B.; Kedziora-Chudczer, L. (Astronomical Society of the Pacific, 2008)
      Interstellar scintillation has been shown to be primarily responsible for intra-day variability exhibited by extragalactic sources at centimeter wavelengths. The recent MASIV survey has shown that a very high proportion ...
    • Microcavities Using Holey Fibers 

      Hendrickson, Scott M.; Pittman, Todd B.; Franson, James D. (OSA Publishing, 2007)
      Microcavities consisting of microstructured holey fibers and separate end mirrors have been constructed and tested. These devices exhibit excellent transverse-mode confinement and the ability to control the percentage of ...
    • Microscopic bath effects on noise spectra in semiconductor quantum dot qubits 

      Ahn, Seongjin; Sarma, S. Das; Kestner, J. P. (2020-07-07)
      When a system is thermally coupled to only a small part of a larger bath, statistical fluctuations of the temperature (more precisely, the internal energy) of this "sub-bath" around the mean temperature defined by the ...
    • Milliarcsecond Observations of Microarcsecond AGN 

      Lazio, J.; Ojha, R.; Fey, A. L.; Kedziora-Chudczer, L.; Cordes, J. M.; Jauncey, D. L.; Lovell, J. E. (Astronomical Society of the Pacific Conference Series, 2008)
      We report on a multi-wavelength program to examine the core structure of extremely compact AGN and to search for indications of an intergalactic medium. We have conducted Very Long Baseline Array (VLBA) observations of 58 ...