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High-Energy 3He-Rich Solar Particle Events
Kocharov, Leon; Torsti, Jarmo; Thompson, Barbara J. +2 more
Energetic particle observations of the ERNE instrument on board SOHO enable measurements of 3He and 4He fluxes beyond 15 MeV nucleon−1 with good statistical resolution. We report results of a survey of the ERNE observations covering the period from 8 February 1999 to 6 December 2000. We find 10 and 5 days during wh…
The Sun's Distance from the Galactic Plane
Branham, R. L., Jr.
Use is made of 93,106 parallaxes from the Hipparcos catalog, with a mixture of spectrum-luminosity classes, to derive the position of the Galactic plane. The reduction technique, mixed total least squares-least squares, takes into account the errors in the parallaxes, and the condition that the direction cosines of the Galactic pole have unit Eucl…
Reconstructed 3-d magnetic field structure and hard X-ray two ribbons for 2000 Bastille-day event
Yan, Yihua; Huang, Guangli
The Bastille-day event in 2000 produced energetic 3B/X5.6 flare with a halo CME, which had great geo-effects consequently. This event has been studied extensively and it is considered that it follows the two-ribbon flare model. The flare/CME event was triggered by an erupting filament and TRACE observations showed formation of giant arcade structu…
Steady-state event-excluded proton spectra at solar minimum at all heliolatitudes
Armstrong, T. P.; Patterson, J. D.
We present spectra of a steady foreground population of particles in the inner heliosphere observed by the Heliosphere Instrument for Spectra, Composition, and Anisotopy at Low Energies (HISCALE) on board the Ulysses spacecraft. The observed spectra come from the full range of heliolatitudes visited by Ulysses, -80 to +80 degrees, during Ulysses' …
The Star-forming Dwarf Galaxy Populations of Two z ~ 0.4 Clusters: MS 1512.4+3647 and A851
Ferguson, Henry C.; Martin, Crystal L.; Lotz, Jennifer M.
We present the results of a deep narrowband [O II] λ3727 emission line search for faint (g<27), star-forming galaxies in the field of the z=0.37 MS 1512.4+3647 cluster. We find no evidence for an overdensity of emission-line sources relative to the field at z~0.4 and therefore conclude that the MS 1512.4+3647 sample is dominated by field [O II]…
Comparative Absorption and Emission Abundance Analyses of Nebulae: Ion Emission Densities for IC 418
Jenkins, Edward B.; Williams, Robert; Baldwin, Jack A. +1 more
Recent analyses of nebular spectra have resulted in discrepant abundances from CNO forbidden and recombination lines. We consider independent methods of determining ion abundances for emission nebulae, comparing ion emission measures with column densities derived from resonance absorption lines viewed against the central star continuum. Separate a…
Ion isotropy and ion resonant waves in the solar wind: Corrected Cassini observations
Gurnett, D. A.; Dougherty, M. K.; Hospodarsky, G. B. +3 more
In an earlier paper [, 2001], observations of electric field fluctuations in the range 0.5 to 25 Hz were reported. We have recently found that the data presented in that paper are seriously contaminated by broadband interference which appears to be generated in the spacecraft wake. Wake instabilities have been found by others, but the plasma condi…
The brightness temperature problem in extreme intra-day variable quasars: a model for PKS 0405-385
Protheroe, R. J.
I re-examine the brightness temperature problem in PKS 0405-385, which is an extreme intra-day variable radio quasar with an inferred brightness temperature of ~5 × 1014 K at 5 GHz, well above the Compton catastrophe limit of ~1011 K that is reached when the synchrotron photon energy density exceeds the energy density of the …
The in-flight background of IBIS/PICsIT
Di Cocco, G.; Malizia, A.; Bassani, L. +3 more
The PICsIT instrument is the high-energy imaging detector of IBIS on board INTEGRAL and comprises 4096 individual scintillator elements each working in the energy range from about 175 keV to 10 MeV. Images of the sky are created using the coded aperture technique wherein each point in the detection plane contributes to the final image. For this re…
IBIS ground calibration
Di Cocco, G.; Malaguti, G.; Bird, A. J. +13 more
We present an overview of results obtained from IBIS ground calibrations. The spectral and spatial characteristics of the detector planes and surrounding passive materials have been determined through a series of calibration campaigns. Measurements of pixel gain, energy resolution, detection uniformity, efficiency and imaging capability are presen…