Search Publications
Acceleration of solar wind ions by oblique interplanetary shocks
Forsyth, R.; Baring, M. G.; Ogilvie, K. W. +1 more
This paper compares observations of proton distributions made by the SWICS ion mass spectrometer on Ulysses at nearby interplanetary shocks with Monte Carlo simulations of particle acceleration at oblique collisionless shocks. The shock parameters are obtained from upstream measurements of the solar wind and magnetic field, and the input particles…
Expanding our knowledge of the heliosphere
Page, D. E.
Milestones on our road to understanding the heliosphere between 1950 and 1988 are recalled. Among these are early studies of solar energetic particles suggesting a heliospheric boundary at 5 AU, the discovery of the solar wind and the sectored nature of the interplanetary magnetic field. Recent results, particularly from the Ulysses spacecraft, co…
ULYSSES energetic ion observations during the declining phase of solar cycle 22
Sanderson, T. R.
The Ulysses spacecraft was launched in October 1990, just after the maximum of solar cycle 22. Part of the journey to Jupiter was during one of the most active periods of solar activity recorded so far. Solar activity remained exceptionally high for many months after launch, solar energetic particles dominating the particle observations at Ulysses…
Some problems of the detection of the high energy gamma-radiation in space
Fradkin, M. I.; Ginzburg, V. L.; Kurnosova, L. V. +8 more
The flux of the diffuse gamma-radiation in the Galaxy was measured with the instruments on board of the satellites COS-B and Compton Gamma Ray Observatory (CGRO). It was shown that the spectrum of the diffuse gamma-rays N(E) in the energy range from very low energy (some tens keV) up to some GeV may be represented by the expression N(E) = AE^kdE, …
On the minimum fluxes of low-energy ions (0.5 MeV/nuc - 8 MeV/nuc) at high heliospheric latitudes
Krupp, N.; Keppler, E.; Fraenz, M. +3 more
The quiet-time fluxes of ions from 0.5 MeV/nuc to 7 MeV/nuc (for oxygen) have been studied for the time period between mid-1993 through the first 104 days of 1994. During this time period Ulysses was below the heliographic current sheet. We find that at the quietest times, the ion population is dominated by the ACR component. For more active times…
The application of network synthesis to repeating classical gamma-ray bursts
Hurley, K.; Kouveliotou, C.; Laros, J. +3 more
It has been suggested that the BATSE gamma-ray burst catalog contains several groups of bursts clustered in space or in space and time, which provide evidence that a substantial fraction of the classical gamma-ray burst sources repeat. Because many of the bursts in these groups are weak, they are not directly detected by the Ulysses GRB experiment…
Simultaneous UV, optical and radio monitoring of the BL Lac object OJ 287 in March 1993
Maraschi, L.; Pian, E.; Quirrenbach, A. +26 more
The BL Lacertae object OJ 287 was intensively monitored with the IUE satellite from 1993 March 15 to 20 in the 2000-3000 Angstroms wavelength region. The very low emission state of the source hampered the detection during part of the 23 performed exposures. The light curve at 2650 Angstroms constructed with the 11 best images exhibits a variable t…
Corotation of Jupiter's three-dimensional magnetosphere
Lanzerotti, L. J.; Maclennan, C. G.; Hawkins, S. E., III +1 more
An understanding of the corotational characteristics of planetary magnetospheres is essential for a complete description and comprehension of the plasma physics of these astrophysical objects. The corotational properties of Jupiter's magnetosphere have been revealed by data from the Voyager and Ulysses spacecraft. The near-equatorial hot plasma sh…
Modulation of galactic cosmic ray particles observed on board the ULYSSES spacecraft
Sierks, H.; Kunow, H.; Wibberenz, G. +9 more
The cosmic ray flux observed with the Kiel Electron Telescope on board the ULYSSES spaceprobe varies with solar activity as well as with heliospheric position. Determination of spatial gradients requires a careful analysis of the influences of the current sheet tilt angle, the number of major solar flares, interplanetary shocks and interaction reg…
The broad band energy distribution of the misaligned gamma-ray blazar PKS 0521-365
Maraschi, L.; Ghisellini, G.; Pian, E. +4 more
Simultaneous UV and X-ray observations of the blazar PKS 0521-365 are combined with radio, IR, optical and gamma-ray data taken at different epochs to study the overall emission from 10^9 to 10^23 Hz. The energy distribution declines from the IR to the UV range (alpha_opt-UV = 1.4 +/- 0.1), buthardens at higher frequencies. The remarkably flat X-r…