Institution
International Space Science Institute
Nonprofit•Bern, Switzerland•
About: International Space Science Institute is a nonprofit organization based out in Bern, Switzerland. It is known for research contribution in the topics: Solar wind & Comet. The organization has 120 authors who have published 858 publications receiving 25772 citations. The organization is also known as: ISSI.
Topics: Solar wind, Comet, Stars, Heliosphere, Coronal mass ejection
Papers published on a yearly basis
Papers
More filters
••
Spanish National Research Council1, University of Geneva2, University of Cagliari3, INAF4, University of Palermo5, International Space Science Institute6, University of Western Sydney7, Max Planck Society8, University of Amsterdam9, ASTRON10, National Radio Astronomy Observatory11, Commonwealth Scientific and Industrial Research Organisation12, University of British Columbia13, Catalan Institution for Research and Advanced Studies14
TL;DR: Observations of accretion-powered, millisecond X-ray pulsations from a neutron star previously seen as a rotation- powered radio pulsar show the evolutionary link between accretion and rotation-powered millisecond pulsars, but also that some systems can swing between the two states on very short timescales.
Abstract: We present the discovery of IGR J18245-2452, the first millisecond pulsar ob- served to swing between a rotation-powered, radio pulsar state, and an accretion-powered X-ray pulsar state (31). This transitional source represents the most convincing proof of the evolutionary link shared by accreting neutron stars in low mass X-ray binaries, and ra- dio millisecond pulsars. It demonstrates that swings between these two states take place on the same time-scales of luminosity variations of X-ray transients, and are therefore most easily interpreted in terms of changes in the rate of mass in-flow. While accreting mass, the X-ray emission of IGR J18245-2452 varies dramatically on time-scales ranging from a second to a few hours. We interpret a state characterised by a lower flux and pulsed fraction, and by sudden increases of the hardness of the X-ray emission, in terms of the onset of a magnetospheric centrifugal inhibition of the accretion flow. Prospects of finding new members of the newly established class of transitional pulsars are also briefly discussed.
466 citations
••
TL;DR: In this paper, the average solar wind charge state and elemental composition of nearly 40 ion species of He, C, N, O, Ne, Mg, Si, S, and Fe observed with the Solar Wind Ion Composition Spectrometer on Ulysses.
Abstract: Using improved, self-consistent analysis techniques, we determine the average solar wind charge state and elemental composition of nearly 40 ion species of He, C, N, O, Ne, Mg, Si, S, and Fe observed with the Solar Wind Ion Composition Spectrometer on Ulysses. We compare results obtained during selected time periods, including both slow solar wind and fast streams, concentrating on the quasi-stationary flows away from recurrent or intermittent disturbances such as corotating interaction regions or coronal mass ejections. In the fast streams the charge state distributions are consistent with a single freezing-in temperature for each element, whereas in the slow wind these distributions appear to be composed of contributions from a range of temperatures. The elemental composition shows the well-known first ionization potential (FIP) bias of the solar wind composition with respect to the photosphere. However, it appears that our average enrichment factor of low-FIP elements in the slow wind, not quite a factor of 3, is smaller than that in previous compilations. In fast streams the FIP bias is found to be yet smaller but still significantly above 1, clearly indicating that the FIP fractionation effect is also active beneath coronal holes from where the fast wind originates. This imposes basic requirements upon FIP fractionation models, which should reproduce the stronger and more variable low-FIP bias in the slow wind and a weaker (and perhaps conceptually different) low-FIP bias in fast streams. Taken together, these results firmly establish the fundamental difference between the two quasi-stationary solar wind types.
445 citations
••
Max Planck Society1, University of Padua2, Aix-Marseille University3, Spanish National Research Council4, International Space Science Institute5, European Space Research and Technology Centre6, Uppsala University7, Braunschweig University of Technology8, German Aerospace Center9, University of Maryland, College Park10, Pierre-and-Marie-Curie University11, Centre national de la recherche scientifique12, INAF13, University of Trento14, Planetary Science Institute15, Macau University of Science and Technology16, National Central University17, European Space Agency18, NASA Lunar Science Institute19, Instituto Nacional de Técnica Aeroespacial20, University of Bern21, University of Cologne22
TL;DR: Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck, which raises the question of whether the two Lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss.
Abstract: Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen consistently. The nucleus rotates about the principal axis of momentum. The surface morphology suggests that the removal of larger volumes of material, possibly via explosive release of subsurface pressure or via creation of overhangs by sublimation, may be a major mass loss process. The shape raises the question of whether the two lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss.
421 citations
••
INAF1, Parthenope University of Naples2, Max Planck Society3, Spanish National Research Council4, Aix-Marseille University5, International Space Science Institute6, European Space Agency7, Polish Academy of Sciences8, Uppsala University9, Braunschweig University of Technology10, University of Maryland, College Park11, University of Padua12, Paris Diderot University13, Versailles Saint-Quentin-en-Yvelines University14, European Space Research and Technology Centre15, Selex ES16, University of Trento17, Virginia Tech18, University of Florida19, Open University20, German Aerospace Center21, National Central University22, University of Kent23, University of Granada24, Centre national de la recherche scientifique25, Instituto Nacional de Técnica Aeroespacial26, University of Bern27, Jet Propulsion Laboratory28
TL;DR: In this article, the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency's Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko was used to detect 35 outflowing grains of mass 10−10 to 10−7 kilograms.
Abstract: Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency’s Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astronomical units inbound, GIADA and OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) detected 35 outflowing grains of mass 10−10 to 10−7 kilograms, and 48 grains of mass 10−5 to 10−2 kilograms, respectively. Combined with gas data from the MIRO (Microwave Instrument for the Rosetta Orbiter) and ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instruments, we find a dust/gas mass ratio of 4 ± 2 averaged over the sunlit nucleus surface. A cloud of larger grains also encircles the nucleus in bound orbits from the previous perihelion. The largest orbiting clumps are meter-sized, confirming the dust/gas ratio of 3 inferred at perihelion from models of dust comae and trails.
373 citations
••
TL;DR: In this paper, a detailed, general relativistic approach to model this irradiation for different geometries of the primary X-ray source is presented, including the standard point source on the rotational axis as well as more jet-like sources, which are radially elongated and accelerating.
Abstract: X-ray irradiation of the accretion disc leads to strong reflection features, which are then broadened and distorted by relativistic effects. We present a detailed, general relativistic approach to model this irradiation for different geometries of the primary X-ray source. These geometries include the standard point source on the rotational axis as well as more jet-like sources, which are radially elongated and accelerating. Incorporating this code in the RELLINE model for relativistic line emission, the line shape for any configuration can be predicted. We study how different irradiation geometries affect the determination of the spin of the black hole. Broad emission lines are produced only for compact irradiating sources situated close to the black hole. This is the only case where the black hole spin can be unambiguously determined. In all other cases the line shape is narrower, which could either be explained by a low spin or an elongated source. We conclude that for those cases and independent of the quality of the data, no unique solution for the spin exists and therefore only a lower limit of the spin value can be given
363 citations
Authors
Showing all 122 results
Name | H-index | Papers | Citations |
---|---|---|---|
Franz E. Bauer | 118 | 939 | 58465 |
Gilles Chabrier | 95 | 384 | 40066 |
Tamas I. Gombosi | 84 | 612 | 26497 |
André Balogh | 81 | 546 | 22494 |
Isabelle Baraffe | 72 | 287 | 21612 |
Anny Cazenave | 72 | 276 | 20198 |
Travis S. Metcalfe | 70 | 239 | 17016 |
Mark Sargent | 66 | 217 | 14925 |
Nathan A. Schwadron | 65 | 495 | 16768 |
G. Paschmann | 61 | 185 | 15887 |
Joachim Wambsganss | 59 | 310 | 13732 |
J. Geiss | 56 | 191 | 9427 |
Tilman Spohn | 56 | 195 | 9042 |
Lennart Bengtsson | 55 | 210 | 13109 |
Rudolf A. Treumann | 50 | 311 | 9004 |