Now showing items 1-20 of 755

    • 2006 May-July major radio flare episodes in Cygnus X-3: Spectrotiming analysis of the X-ray data 

      Koljonen, Karri I. I.; McCollough, Michael L.; Hannikainen, Diana Carina; Droulans, Robert (2013)
      We analyse in detail the X-ray data of the microquasar Cygnus X-3 obtained during major radio flaring episodes in 2006 with multiple observatories. The analysis consists of two parts: probing the fast (~1min) X-ray spectral ...
    • The 2010 very high energy y-ray flare and 10 years of multi-wavelength observations of M 87 

      Cara, Mihai; Perlman, Eric S.; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Barres de Almeida, U. (2012-02-02)
      The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3 – 6) × 109 M ☉) provides a unique opportunity to investigate the origin of very high energy (VHE; E > 100 GeV) γ-ray ...
    • 2MASS J0516288+260738: Discovery of the first eclipsing late K + Brown dwarf binary system? 

      Schüh, Sonja L.; Handler, Gerald; Drechsel, Horst; Hauschildt, Peter H.; Dreizler, Stefan; Medupe, R.; Karl, C. A.; Napiwotzki, Ralf; Kim, Seunglee; Wood, Matt A. (2003-11)
      We report the discovery of a new eclipsing system less than one arcminute south of the pulsating DB white dwarf KUV 05134+2605 . The object could be identified with the point source 2MASS J0516288+260738 published by the ...
    • The ~60-year power spectral peak of the magnetic variations around London and the Earth's rotation rate fluctuations 

      Rong-Sheng, Jin (1989)
      Maximum entropy spectral analysis has been applied to the annual mean magnetic data around London for the years 1839-1974. These data were compiled by Malin and Bullard. The existence of a ~60 yr spectral line is clearly ...
    • 70 DA white dwarfs identified in LAMOST pilot survey 

      Luo, A.L.; Oswalt, Terry D.; Zhao, J.K.; Zhao, G. (2013-06)
      We present a spectroscopically identified catalog of 70 DA white dwarfs (WDs) from the LAMOST pilot survey. Thirty-five are found to be new identifications after cross-correlation with the Eisenstein et al. and Villanova ...
    • The 72-h WEBT microvariability observation of blazar S5 0716+714 in 2009 

      Bhatta, G.; Webb, James R.; Hollingsworth, H.; Dhalla, S.; Khanuja, A.; Bachev, Rumen S.; Blinov, Dmitry A.; Böttcher, Markus; Bravo Calle, O. J A; Vennes, Stéphane (2013-10-10)
      Context. The international Whole Earth Blazar Telescope (WEBT) consortium planned and carried out three days of intensive micro-variability observations of S5 0716+714 from February 22, 2009 to February 25, 2009. This ...
    • Abundance of elements beyond the iron group in cool do white dwarfs 

      Chayer, Pierre; Vennes, Stéphane; Dupuis, Jean François; Kruk, Jeffrey W. (2005-09-10)
      We report the presence of elements beyond the iron group in the atmospheres of the cool DO white dwarfs HD 149499 B and HZ 21. Photospheric lines of germanium (Z = 32), arsenic (33), selenium (34), tin (50), tellurium (52), ...
    • Abundances and energy spectra of corotating interaction region heavy ions observed during solar cycle 23 

      Mason, Glenn M.; Leske, Richard A.; Desai, Mihir I.; Cohen, Christina M S; Dwyer, Joseph R.; Mazur, Joseph E.; Mewaldt, Richard A.; Gold, Robert E.; Krimigis, Stamatios M. (2008-05-10)
      Using instruments on the ACE spacecraft, we surveyed the heavy-ion spectra and composition over the range He– Fe for 41 corotating interaction regions (CIRs) during 1998–2007. Below~ 1 MeV nucleon^-1 the spectra are power ...
    • Abundances of heavy and ultraheavy ions in ³He-rich solar flares 

      Mason, Glenn M.; Mazur, Joseph E.; Dwyer, Joseph R.; Jokipii, Jack Randy; Gold, Robert E.; Krimigis, Stamatios M. (2004-05-01)
      We have surveyed ³He-rich solar energetic particle (SEP) events over the period 1997 September-2003 April in order to characterize abundances of heavy ions near 400 keV nucleonˉ¹. The first part of the study focuses on 20 ...
    • Acceleration of low-energy ions at parallel shocks with a focused transport model 

      Zuo, Pingbing; Zhang, Ming; Rassoul, Hamid K. (2013-04-10)
      We present a test particle simulation on the injection and acceleration of low-energy suprathermal particles by parallel shocks with a focused transport model. The focused transport equation contains all necessary physics ...
    • Acceleration of suprathermal particles by compressional plasma wave trains in the solar wind 

      Zhang, Ming (2010-12-04)
      This paper presents a calculation of particle acceleration by an idealized compressional plasma wave train. In this model, suprathermal particles, such as pickup ions, are continuously injected into a wave train consisting ...
    • Acceleration of ³He nuclei at interplanetary shocks 

      Desai, Mihir I.; Mason, Glenn M.; Dwyer, Joseph R.; Mazur, Joseph E.; Smith, Charles W.; Skoug, Ruth M. (2001-05-20)
      e have surveyed the 0.5-2.0 MeV nucleonˉ¹ ion composition of 56 interplanetary (IP) shocks observed with the Ultra - Low-Energy Isotope Spectrometer on board the Advanced Composition Explorer from 1997 October 1 through ...
    • AGILE detection of Cygnus X-3 γ-ray active states during the period mid-2009/mid-2010 

      Bulgarelli, A.; Tavani, Marco; Chen, Andrew; Evangelista, Yuri; Trifoglio, Massimo; Gianotti, Fulvio; Piano, Giovanni; Sabatini, Sabina; Striani, Edoardo; Hannikainen, Diana Carina (2012-02)
      Context. Cygnus X-3 (Cyg X-3) is a well-known microquasar producing variable emission at all wavelengths. Cyg X-3 is a prominent X-ray binary producing relativistic jets, and studying its high energy emission is crucial ...
    • The AGILE monitoring of Cygnus X-3: transient gamma-ray emission and spectral constraints 

      Piano, Giovanni; Tavani, Marco; Trois, Alessio; Giuliani, Andrea; Bulgarelli, Andrea; Evangelista, Yuri; Coppi, Paolo S.; Del Monte, Ettore D.; Sabatini, Sabina; Hannikainen, Diana Carina (2012-09-14)
      We present the AGILE-GRID (Astro-rivelatore Gamma a Immagini LEggero – Gamma-Ray Imaging Detector) monitoring of Cygnus X-3, during the period between November 2007 and July 2009. We report here the whole AGILE-GRID ...
    • Analysis of fundamental interactions capable of producing neutrons in thunderstorms 

      Babich, Leonid P.; Bochkov, Evgeniǐ I.; Kutsyk, Igor M.; Rassoul, Hamid K. (2014-05-13)
      Elementary processes capable of producing neutrons in thunderstorms are analyzed. Efficiency is evaluated of nuclear fusion, photonuclear reaction, electrodisintegration, and reaction inverse to the β-decay. An extraordinary ...
    • Analysis of scanning tunneling optical spectroscopy applied to narrow gap semiconductors 

      Patterson, James D.; Mantovani, James G. (1997-07-07)
      Homogeneous II-VI narrow gap semiconducting alloys are of interest because of their use in infrared detectors. These compound semiconductor materials are inherently difficult to grow in bulk due to gravity induced convective ...
    • Analysis of the experiment on registration of X-rays from the stepped leader of a cloud-to-ground lightning discharge 

      Babich, Leonid P.; Kutsyk, Igor M.; Donsko, Evgeni N.; Dwyer, Joseph R. (2013-05)
      Using a Monte Carlo technique to simulate the transport of runaway electrons (REs) and X-rays in the atmosphere and through attenuators covering detectors, we have modeled the results of experiments to detect X-rays from ...
    • Analytic variational method for Hamiltonian lattice gauge theory in 3 + 1 dimensions 

      Huang, Ming C.; Katoot, Mohammad W. (1990-03-15)
      We present an analytic d in 3 + 1 dimensions for Hamiltonian lattice gauge theory. This method is based on Batrouni's mean-plaquette method and space integration. The Abelianized Bianchi identities are used and a detailed ...
    • An analytical approach for calculating energy spectra of relativistic runaway electron avalanches in air 

      Cramer, Eric S.; Dwyer, Joseph R.; Arabshahi, Shahab; Liu, Ningyu; Rassoul, Hamid K.; Vodopiyanov, Igor (2014-09-15)
      Simplified equations describing the transport and energy spectrum of runaway electrons are derived from the basic kinematics of the continuity equations. These equations are useful in modeling the energy distribution of ...
    • An ancient extrasolar system with five sub-earth-size planets 

      Ragozzine, Darin A.; Campante, Tiago L.; Barclay, Thomas S.; Swift, Jonathan J.; Huber, Daniel; Adibekyan, V. Zh.; Cochran, William D.; Burke, Christopher J.; Isaacson, Howard T.; Quintana, Elisa V. (2015-01-27)
      The chemical composition of stars hosting small exoplanets (with radii less than four Earth radii) appears to be more diverse than that of gas-giant hosts, which tend to be metal-rich. This implies that small, including ...