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Optical, X-ray and γ-ray observations of compact objects in globular clusters

Grindlay, J. E.

In the past three years, a new era of study of globular clusters has begun with multiwavelength observations from the current generation of astronomical telescopes in space. We review the recent results obtained from our studies of compact binaries and x-ray sources in globulars with ROSAT and HST as well as our balloon-borne hard x-ray telescope …

Dust in the planetary system

Grün, E.

A continuous spectrum of particulates ranging from m-sized objects down to molecular sizes is found almost everywhere in the planetary system: in interplanetary space and surrounding planets. Remote observations and in situ analysis provide information on their abundance and properties. Zodiacal dust particles displayed their low eccentricity, low…

Pulsar studies with GRO-COMPTEL

Strong, A. W.; Schönfelder, V.; Kuiper, L. +9 more

Pulsar measurements performed by the experiment COMPTEL, aboard the Compton Gamma Ray Observatory, are described. The main results refer to the Crab and Vela pulsars whose pulse shape characteristics are given in some detail and light curves are compared with those above 50 MeV, as observed by the COS-B satellite. No other gamma-ray pulsars have b…

Anisotropy measurements and spectra from a solar proton event in March 1991

Balogh, A.; Forsyth, R. J.; Cowley, S. W. H. +2 more

We use observations from the Anisotropy Telescopes on the Ulysses spacecraft to determine the omnidirectional flux profile of protons in the energy range 0.7 - 1.3 MeV, during the solar proton event that began on 23 Mar 1991. We also show the spectral index throughout the event at 0.7 - 2.2 MeV and at 2.2 - 6.5 MeV, with three example spectra, one…

Ulysses-its status and prospects

Wenzel, K. -P.

The Ulysses spacecraft is in a high-inclination solar orbit to reach the south polar regions of the Sun in mid-1994 and the north polar regions about one year later. The spacecraft and its nine scientific instruments are in good health. An extended mission, i.e. a second orbit with polar passes about half an 11-year solar cycle later, is scientifi…

Observing the Solar Wind Between 1 and 4 AU with the Radio Receiver on Ulysses

Pantellini, F.; Forsyth, R. J.; Stone, R. G. +8 more

Radio waves in the heliosphere

Bougeret, J. -L.

Solar radio emissions at long wavelengths (wavelengths greater than 10 m or frequencies smaller than 30 MHz) are produced in the upper corona and in the interplanetary medium (the Heliosphere), sometimes at very large distances from the Sun, up to the orbit of Jupiter and beyond. Solar radio emissions are produced by the passage of energetic parti…

Ulysses observations of a pure electron event and its associated type III radio emission on December 15, 1990

Chaizy, P.; Pick, M.; Forsyth, R. +5 more

We describe an electron event associated with a type III burst observed by Ulysses. This event was observed when the spacecraft crossed the 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 and energetic electron anisotr…

Einstein and EXOSAT observations of Geminga revisited

Bignami, G. F.; Mereghetti, S.; Caraveo, P.

We have re-analyzed the archive Einstein IPC and EXOSAT CMA x-ray data of Geminga, in the light of the recent discoveries on this source. The results of a search for the 237 msec periodicity are consistent with a pulsed fraction decreasing with x-ray energy. We have combined the EXOSAT CMA and the Einstein data in order to limit the spectral param…

The Decay Phase of the March-April, 1991 Low-Energy Particle Events Observed at Ulysses and Earth

Simnett, G. M.; Lanzerotti, L. J.; Armstrong, T. P. +2 more