Search Publications
Interstellar dust in the heliosphere
Mann, I.; Morfill, G. E.; Gruen, E. +5 more
A flow of µm-sized interstellar grains has been identified with the Ulysses dust detector in the outer solar system at about 5 AU from the Sun. The observed flux is 1.5x10^-4^m^-2^/s of particles of mean mass 3x10^-13^g, which corresponds to a mass flux of 5x10^-17^g/m^2^/s. The particles on hyperbolic trajectories have radiants which are co…
Interstellar oxygen, nitrogen and neon in the heliosphere
Geiss, J.; Galvin, A. B.; Mall, U. +3 more
Oxygen, nitrogen and neon pick-up ions of interstellar origin were detected for the first time with the Solar Wind Ion Spectrometer (SWICS) on board Ulysses. The interstellar origin of these ions is established by the following criteria: (a) they are singly charged, (b) they have the broad velocity distributions characteristic of pick-up ions, wit…
Interplanetary type III radio bursts that approach the plasma frequency: ULYSSES observations.
Hoang, S.; Leblanc, Y.; Dulk, G. A.
We study a set of solar type III radio bursts where the emission is visible from the high-frequency limit of the radio astronomy receiver of the Ulysses Unified Radio and Plasma wave (URAP) experiment down to low frequencies, sometimes near the plasma frequency, and where Langmuir wave spikes are recorded by the radio and/or plasma receivers. For …
Origin of the O^+^ pick-up ions in the heliosphere.
Geiss, J.; Mall, U.; Gloeckler, G.
The main sources for the ions in the interplanetary medium are the solar wind and the interstellar gas intruding into the heliosphere. Other sources, i.e. comets and planets can, however, contribute significantly locally. We present approximate expressions for deriving fluxes of pick-up ions originating from local neutral gas sources. Since the Io…
Simultaneous observations of γ-ray bursts with Phebus/Granat and ULYSSES GRB.
Hurley, K.; Sunyaev, R.; Sommer, M. +9 more
We compare the characteristics of 35 gamma-ray bursts (GRBs) detected simultaneously by Phebus aboard Granat and the Ulysses GRB experiment. Phebus observes a medium to high energy range (100 keV - 100 MeV), while the Ulysses GRB detector is sensitive to lower energy photons (25-150 keV). Comparison of the peak counts recorded by these two instrum…
Observational constraints on the inter-binary stellar flare hypothesis for the gamma-ray bursts
Rao, A. R.; Vahia, M. N.
The Gamma Ray Observatory/Burst and Transient Source Experiment (GRO/BATSE) results on the Gamma Ray Bursts (GRBs) have given an internally consistent set of observations of about 260 GRBs which have been released for analysis by the BATSE team. Using this database we investigate our earlier suggestion (Vahia and Rao, 1988) that GRBs are inter-bin…
Observations by ULYSSES of a pure electron event and its associated type III radio emission of 15 December 1990
Chaizy, P.; Pick, M.; Forsyth, R. +8 more
We describe an interplanetary electron event associated with a type III radio burst observed by Ulysses at 1.37 AU. This event was observed when the spacecraft crossed a region of strong compression between a fast and a slow solar wind stream, characterized by a relatively high density and a complex behaviour of the plasma density, magnetic field …
Particle acceleration by an interplanetary shock-pair seen at ULYSSES at 3.15 AU.
Tappin, S. J.; Lanzerotti, L. J.; Roelof, E. C.
Observations from the HI-SCALE instrument on Ulysses of the ions and electrons associated with an interplanetary shock-pair at about 3.15 AU are presented. An empirical model is used to derive the evolution of the particle distribution in the solar wind frame. The forward shock is shown to be the primary source of ion acceleration, while the weake…