Now showing items 265-284 of 845

    • Gamma-ray active galactic nucleus type through machine-learning algorithms 

      Hassan, T.; Mirabal, N.; Contreras, J. L.; Oya, I. (Oxford Academic, 2013-01-01)
      The Fermi Gamma-ray Space Telescope (Fermi) is producing the most detailed inventory of the gamma-ray sky to date. Despite tremendous achievements approximately 25 per cent of all Fermi extragalactic sources in the Second ...
    • Gamma-ray Beacons at the Dawn of the Universe 

      Gasparrini, D.; Paliya, V.S.; Ajello, M.; Ojha, R.; Fermi-LAT Collaboration (Proceedings of Science, 2017-07-10)
      Gamma ray detected high-redshift blazars (z>3) are intrinsically interesting since they inform us about the evolution of gamma-ray blazars and are, by definition, some of the more luminous blazars in the Universe. It has ...
    • The Gamma-Ray Blazar PKS 0208-512, a Multi-Wavelength Investigation 

      Blanchard, J. M.; Lovell, J. E. J.; Dickey, J.; Ojha, R.; Kadler, M.; Nesci, R.; Edwards, P. G.; Stevens, J.; Dutka, M.; Muller, C.; Pursimo, T. (2012-06-27)
      The gamma-ray blazar PKS 0208-512 has shown strong periods of flaring, at all frequencies from radio to gamma-ray. This has led to its inclusion in the TANAMI project, which tracks the jets of southern AGN using VLBI as ...
    • Gamma-Ray Blazars within the First 2 Billion Years 

      Ojha, R.; Ferrara, E. C.; Hays, E.; Perkins, J. S.; Rani, B.; Thompson, D. J. (IOP, 2017-02-27)
      The detection of high-redshift (z > 3) blazars enables the study of the evolution of the most luminous relativistic jets over cosmic time. More importantly, high-redshift blazars tend to host massive black holes and can ...
    • Gamma-ray Clues to the Relativistic Jet Dichotomy 

      Meyer, Eileen T.; Fossati, Giovanni; Georganopoulos, Markos; Lister, Matthew L. (2011-11-28)
      In examining a select sample of over 200 blazars of known jet kinetic power (L_kin) and well-characterized SEDs, we found (Meyer et al., 2011) that Intermediate synchrotron-peaking (ISP) blazars may have lower gamma-ray ...
    • A gamma-ray determination of the Universe’s star formation history 

      Ojha, R.; et al. (American Association for the Advancement of Science, 2018-11-30)
      The light emitted by all galaxies over the history of the Universe produces the extragalactic background light (EBL) at ultraviolet, optical, and infrared wavelengths. The EBL is a source of opacity for gamma rays via ...
    • Gamma-ray emission in radio galaxies under the VLBI scope I. Parsec-scale jet kinematics and high-energy properties of γ-ray-detected TANAMI radio galaxies 

      Angioni, R.; Ros, E.; Kadler, M.; Ojha, R.; Müller, C.; Edwards, P. G.; Burd, P. R.; Carpenter, B.; Dutka, M. S.; Gulyaev, S.; Hase, H.; Horiuchi, S.; Krauß, F.; Lovell, J. E. J.; Natusch, T.; Phillips, C.; Plötz, C.; Quick, J. F. H.; Rösch, F.; Schulz, R.; Stevens, J.; Tzioumis, A. K.; Weston, S.; Wilms, J.; Zensus, J. A. (EDP sciences, 2019-07-15)
      Aims. In the framework of the multi-wavelength and very long baseline interferometry (VLBI) monitoring program TANAMI (Tracking Active Nuclei with Austral Milliarcsecond Interferometry), we study the evolution of the ...
    • Gamma-ray emission in radio galaxies under the VLBI scope II. The relationship between gamma-ray emission and parsec-scale jets in radio galaxies 

      Angioni, R.; Ros, E.; Kadler, M.; Ojha, R.; Mueller, C.; Edwards, P.G.; Burd, P.R.; Carpenter, B.; Dutka, M. S.; Gulyaev, S.; Hase, H.; Horiuchi, S.; Krauss, F.; Lovell, J.E.J.; Natusch, T.; Phillips, C.; Ploetz, C.; Quick, J. F. H.; Roesch, F.; Schulz, R.; Stevens, J.; Tzioumis, A. K.; Weston, S.; Wilms, J.; Zensus, J. A. (EDP sciences, 2020-07-20)
      Aims. This is the second paper in our series studying the evolution of parsec-scale radio emission in radio galaxies in the Southern Hemisphere. Following our study of the radio and high-energy properties of γ-ray-emitting ...
    • The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004−447 

      Kreikenbohm, A.; Schulz, R.; Kadler, M.; Wilms, J.; Markowitz, A.; Chang, C. S.; Carpenter, B.; Elsässer, D.; Gehrels, N.; Mannheim, K.; Müller, C.; Ojha, R.; Ros, E.; Trüstedt, J. (EDP sciences, 2015-12-23)
      As part of the TANAMI multiwavelength progam, we discuss new X-ray observations of the γ-ray and radio-loud narrow line Seyfert 1 galaxy (γ-NLS1) PKS 2004−447. The active galaxy is a member of a small sample of radio-loud ...
    • The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004−447 

      Schulz, R.; Kreikenbohm, A.; Kadler, M.; Ojha, R.; Ros, E.; Stevens, J.; Edwards, P. G.; Carpenter, B.; Elsässer, D.; Gehrels, N.; Grossberger, C.; Hase, H.; Horiuchi, S.; Lovell, J. E. J.; Mannheim, K.; Markowitz, A.; Müller, C.; Phillips, C.; Plötz, C.; Quick, J.; Trüstedt, J.; Tzioumis, A. K.; Wilms, J. (EDP sciences, 2016-04-01)
      Context. Γ-ray-detected radio-loud narrow-line Seyfert 1 (γ-NLS1) galaxies constitute a small but interesting sample of the γ-ray-loud AGN. The radio-loudest γ-NLS1 known, PKS 2004−447, is located in the southern hemisphere ...
    • Gamma-ray flares from the blazars TXS 2241+406, Ton 599, and 4C +01.02 

      Ojha, Roopesh; Carpenter, Bryce (The Astronomer's Telegram, 2015-11-22)
    • Gamma-Ray Science in the 2020s 

      Wagner, Stefan
    • Gamma-ray Scintillator Fiber Tracker 

      Cannady, N. W.; Caputo, R.; Venere, L. Di; Fusco, P.; Gargano, F.; Giglietto, N.; Giordano, F.; Hartmann, D. H.; Kierans, C.; Longo, F.; Loparco, F.; Rando, R.
      We plan to develop and implement a novel ultralight tracker based on scintillating fibers with a spatial resolution below 100 μm, also able to perform precise timing and charge measurements. The fibers will be arranged in ...
    • Generalized Clausius Inequality for Nonequilibrium Quantum Processes 

      Deffner, Sebastian; Lutz, Eric (American Physical Society (APS), 2010-10-19)
      We show that the nonequilibrium entropy production for a driven quantum system is larger than the Bures length, the geometric distance between its actual state and the corresponding equilibrium state. This universal lower ...
    • Generating photon-added states without adding a photon 

      Shringarpure, S.U.; Franson, J.D. (The American Physical Society, 2019-10-02)
      We show that a continuous range of nonclassical states of light can be generated using conditional measurements on the idler mode of an optical parametric amplifier. The output state is prepared by introducing a coherent ...
    • Generation of entangled photon holes using quantum interference 

      Pittman, T.B.; Franson, J.D. (American Physical Society (APS), 2006-10-04)
      In addition to photon pairs entangled in polarization or other variables, quantum mechanics also allows optical beams that are entangled through the absence of the photons themselves. These correlated absences, or “entangled ...
    • Geocenter Motion Causes and Modeling Approaches 

      Pavlis, Erricos C.; Kuzmicz-Cieslak, Magdalena (NASA, 2008-10)
      We concentrate here on Earth’s “Center of Mass”, the geocenter, the fidelity and accuracy with which SLR defines its average location over decades and monitors its seasonal variations associated with the redistribution of ...
    • GEOCON: Geodetic System Ties Using a CubeSat Constellation 

      Pavlis, Erricos C.; Merkowitz, Stephen M.; Beaudoin, Christopher J.; Kuzmicz-Cieslak, Magda; Rowlands, Dave D.; Lemoine, Frank G.
      The accuracy of the Terrestrial Reference Frame (TRF), the foundation for geolocating all Earth Observations, is currently limited by systematic errors in tying together the contributions from the different geodetic ...
    • Geometric quantum speed limits: a case for Wigner phase space 

      Deffner, Sebastian (IOP, 2017-10-20)
      The quantum speed limit is a fundamental upper bound on the speed of quantum evolution. However, the actual mathematical expression of this fundamental limit depends on the choice of a measure of distinguishability of ...
    • The GGOS Bureau of Networks & Observations: An Update on the Space Geodesy Network & the New Implementation Plan for 2017-2018 

      Pearlman, Michael R.; Ma, Chopo; Noll, Carey; Pavlis, Erricos C.; Neilan, Ruth; Saunier, Jerome; Schoene, Tilo; Barzaghi, Ricardo; Thaller, Daniela; Bergstrand, Sten; Mueller, Juergen (National Aeronautics and Space Administration, 2017-04-24)
      Abstract: Working with the IAG geometric services (VLBI, SLR, GNSS, and DORIS) the Bureau continues to advocate for the expansion and upgrade of the space geodesy networks for the maintenance and improvement of the reference ...