Search Publications

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…

Inverse radiation modeling of Titan's atmosphere to assimilate solar aureole imager data of the Huygens probe

Keller, H. U.; Grieger, B.; Markiewicz, W. J. +1 more

During the descent of the Huygens probe through Titan's atmosphere in January 2005, the Descent Imager/Spectral Radiometer (DISR) will perform upward and downward looking measurements at various spectral ranges and spatial resolutions. This internal radiation density could be estimated by radiative transfer calculations for Titan's atmosphere. How…

XMM-Newton local bubble and galactic halo survey

Freyberg, M. J.; Breitschwerdt, D.

Optical identifications in the Marano field XMM-Newton survey

Hasinger, G.; Mignoli, M.; Zamorani, G. +4 more

The ``Marano field'', a deep optical quasar survey field, has been observed by the XMM Newton EPIC camera with 16 overlapping pointings totalling at ~ 120 ksec integration time. Source detection in the merged observations resulted in more than 600 X-ray sources. Here we present the status of optical follow up observations which were undertaken to …