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241.
Galaxy clusters are ideal tracers of the large-scale structure and evolution of the universe. They are thus good probes for the matter content of the universe, the existence of dark matter, and for the statistics of the large-scale structure of the matter distribution. X-ray observations provide a very effective tool to characterize individual galaxy clusters as well as the cluster population. With the detailed analysis of X-ray observations of galaxy clusters the matter composition of clusters is obtained which can be taken as representative of the matter composition of the universe. Based on galaxy cluster surveys in X-rays a census of the galaxy cluster population and statistical measures of the spatial distribution of clusters is obtained. Comparison of the results with predictions from cosmological models yields interesting cosmological model constraints and in particular favours a low density universe. 相似文献
242.
J.-P. Bibring H. Rosenbauer H. Boehnhardt S. Ulamec J. Biele S. Espinasse B. Feuerbacher P. Gaudon P. Hemmerich P. Kletzkine D. Moura R. Mugnuolo G. Nietner B. Pätz R. Roll H. Scheuerle K. Szegö K. Wittmann 《Space Science Reviews》2007,128(1-4):205-220
The paper describes the Rosetta Lander named Philae and introduces its complement of scientific instruments. Philae was launched
aboard the European Space Agency Rosetta spacecraft on 02 March 2004 and is expected to land and operate on the nucleus of
67P/Churyumov-Gerasimenko at a distance of about 3 AU from the Sun. Its overall mass is ~98 kg (plus the support systems remaining
on the Orbiter), including its scientific payload of ~27 kg. It will operate autonomously, using the Rosetta Orbiter as a
communication relay to Earth. The scientific goals of its experiments focus on elemental, isotopic, molecular and mineralogical
composition of the cometary material, the characterization of physical properties of the surface and subsurface material,
the large-scale structure and the magnetic and plasma environment of the nucleus. In particular, surface and sub-surface samples
will be acquired and sequentially analyzed by a suite of instruments. Measurements will be performed primarily during descent
and along the first five days following touch-down. Philae is designed to also operate on a long time-scale, to monitor the
evolution of the nucleus properties. Philae is a very integrated project at system, science and management levels, provided
by an international consortium. The Philae experiments have the potential of providing unique scientific outcomes, complementing
by in situ ground truth the Rosetta Orbiter investigations.
Philae team members are listed in the acknowledgements 相似文献
243.
The ionic charge of solar energetic particles (SEP) as observed in interplanetary space is an important parameter for the
diagnostic of the plasma conditions at the source region and provides fundamental information about the acceleration and propagation
processes at the Sun and in interplanetary space. In this paper we review the new measurements of ionic charge states with
advanced instrumentation onboard the SAMPEX, SOHO, and ACE spacecraft that provide for the first time ionic charge measurements
over the wide energy range of ∼0.01 to 70 MeV/nuc (for Fe), and for many individual SEP events. These new measurements show
a strong energy dependence of the mean ionic charge of heavy ions, most pronounced for iron, indicating that the previous
interpretation of the mean ionic charge being solely related to the ambient plasma temperature was too simplistic. This energy
dependence, in combination with models on acceleration, charge stripping, and solar and interplanetary propagation, provides
constraints for the temperature, density, and acceleration time scales in the acceleration region. The comparison of the measurements
with model calculations shows that for impulsive events with a large increase of Q
Fe(E) at energies ≤1 MeV/nuc the acceleration occurs low in the corona, typically at altitudes ≤0.2 R
S
. 相似文献
244.
N. Tarcea T. Frosch P. Rösch M. Hilchenbach T. Stuffler S. Hofer H. Thiele R. Hochleitner J. Popp 《Space Science Reviews》2008,135(1-4):281-292
This paper introduces Raman spectroscopy and discusses various scenarios where it might be applied to in situ planetary missions. We demonstrate the extensive capabilities of Raman spectroscopy for planetary investigations and argue that this technique is essential for future planetary missions. 相似文献
245.
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248.
M. Kästner P. Köpke H. Quenzel 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(5):119-121
The optical depth of Saharan dustclouds (a component of the radiation budget), which can be clearly seen in satellite images taken over the Atlantic, can be determined from the Meteosat VIS-data. ‘Favourable angles’ between sun, observed point and satellite are chosen so that the optical depth is determined with an inaccuracy of only about 20%.We present several clouds, their change over time, and some of their other interesting features. The results are discussed. 相似文献
249.
B. Ehmann L. Balázs É. Fülöp R. Hargitai P. Kabai B. Péley T. Pólya A. Vargha J. László 《Acta Astronautica》2011,68(9-10):1560-1566
This paper is about a pilot application of narrative psychological content analysis in the psychological status monitoring of Crew 71 of a space analog simulation environment, the Mars Desert Research Station (MDRS). Both the method and its theoretical framework, Scientific Narrative Psychology, are original developments by Hungarian psychologists [5] (László, 2008). The software was NooJ, a multilingual linguistic development environment [11] (Silberztein, 2008). Three measures were conceptualized and assessed: emotional status, team spirit and subjective physical comfort. The results showed the patterns of these three measures on a daily basis at group level, and allowed for detecting individual differences as well. The method is adaptable to languages involved in space psychology, e.g. Russian, French and German in addition to English. 相似文献
250.
C. Fröhlich J.A. Eddy 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(8):121-124
We compile measurements of the total solar irradiance So made in the period 1967 to 1983 from balloons, rockets, and spacecrafts. These data, when corrected for atmospheric and calibration differences, suggest a systematic increase in So of about 0.025% per year. In 1979 and after the ACRIM/SMM and the ERB/NIMBUS data reveal a systematic decrease of about the same magnitude. The period of the early apparent increase embraces a full solar activity cycle of 11 years: hence the effect cannot be that of simple sunspot blocking. This trend of a slow increase followed by a similar decrease is compared with solar diameter measurements obtained from daily meridian transit timings of the Sun made during the same period at the Royal Greenwich Observatory and at the U.S. Naval Observatory. We find in both of these data sets an apparent increase in solar diameter of about 0.03″arc per year during the period of increasing solar irradiance and a weaker suggestion of a similar, subsequent decline. If the apparent trends in diameter and luminosity are real they allow us to estimate the empirical relationship between the two quantities. For this period we find W=ΔlogR/ΔlogL=0.078±0.026. 相似文献