Long-Term Fluences of Solar Energetic Particles from H to Fe

Data from ACE and GOES have been used to measure Solar Energetic Particle (SEP) fluence spectra for H, He, O, and Fe, over the period from October 1997 to December 2005. The measurements were made by four instruments on ACE and the EPS sensor on three GOES satellites and extend in energy from ∼0.1 MeV/nuc to ∼100 MeV/nuc. Fluence spectra for each species were fit by conventional forms and used to investigate how the intensities, composition, and spectral shapes vary from year to year.     

The Far Infrared Explorer (FIRE)

We describe the Far IR Explorer, a MIDEX-class orbital mission designed to survey the entire sky at millimeter and sub-millimeter wavelengths. The primary science goal of FIRE is to map the Cosmic Microwave Background with 20 resolution and 1 ppm precision. In addition, FIRE will measure diffuse radio and infrared emission from the Galaxy with unprecedented sensitivity, and will uniformly survey the entire sky to a limiting flux density of <100 mJy (3 ).     

Studying the evolution of the hot universe with the X-ray evolving universe spectroscopy mission – XEUS

Europe is one of the major partners building the International Space Station (ISS) and European industry, together with ESA, is responsible for many station components including the Columbus Orbital Facility, the Automated Transport Vehicle, two connecting modules and the European Robotic Arm. Together with this impressive list of contributions there is a strong desire within the ESA Member States to benefit from this investment by utilizing the unique capabilities of the ISS to perform world-class science. XEUS is one of the astronomical applications being studied by ESA to utilize the capabilities of the ISS. XEUS will be a long-term X-ray observatory with an initial mirror area of 6 m² at 1 keV that will be expanded to 30 m² following a visit to the ISS. The 1 keV spatial resolution is expected to be 2–5″ half-energy-width. XEUS will consist of separate detector and mirror spacecraft (MSC) aligned by active control to provide a focal length of 50 m. A new detector spacecraft, complete with the next generation of instruments, will also be added after visiting the ISS. The limiting 0.1–2.5 keV sensitivity will then be 4 × 10⁻¹⁸ erg cm⁻² s⁻¹, around 200 times better than XMM-Newton, allowing XEUS to study the properties of the hot baryons and dark matter at high redshift.     

Special issue introduction: Approaching spatial uncertainty visualization to support reasoning and decision making

While research on uncertainty and decision-making has a long history across several disciplines, recent technological developments compel researchers to rethink how to best address and advance the understanding of how humans reason and make decisions under spatial uncertainty. This introduction presents a visual summary graphic to provide an overview of each article in this special issue. Upon viewing these visual summaries, the reader will find that each of these articles covers different topics in the uncertainty visualization domain, offering complementary research in this field. Extending this body of research and finding new ways to explore how these visualizations may help or hinder the analytical and reasoning process of humans continues to be a necessary step towards designing more effective uncertainty visualizations to support reasoning and decision-making.     

New atomic data for the FeXII coronal ion

Various FeXII spectroscopic lines in the UV and EUV range have been proved to be ideal diagnostic tools for measuring electron temperature, density and iron abundance in the solar corona. In the framework of the “IRON PROJECT” we have provided improved theoretical calculations of the atomic data required to analyse the intensity of these lines and to apply the results to SOHO (Solar Heliospheric Observatory) observations. Extensive configuration interaction and relativistic effects have been allowed for in the atomic structure computations which have provided energy levels and an extensive set of radiative data. The e-FeXII collisional problem has been tackled with the multichannel R-matrix method, a close-coupling calculation for the determination of electron impact collision strengths. Final results are presented for FeXII thermally averaged collision strengths, for fine-structure forbidden transitions within the ground configuration.     

The carbonaceous chondrites

The carbonaceous chondrites are a group of stony meteorites characterized by the presence of an appreciable amount of carbonaceous material other than free carbon (diamond and graphite). They have been divided into three subgroups known respectively as Type I, Type II, and Type III. Analyses of Type I meteorites show about 3–5% of carbon and 20% of combined water; they consist largely of hydrated magnesium-iron silicate, magnetite, and magnesium sulfate, contain no chondrules, and have a density about 2.2. Analyses of Type II meteorites show about 2–3% of carbon and 10–15% of combined water; they consist of a groundmass of hydrated magnesium-iron silicate enclosing chondrules of olivine and pyroxene which are almost iron-free, and have a density of 2.6–2.9. Analyses of Type III meteorites show about 0.5–2% of carbon and 2% combined water; they consist largely of olivine (often variable in composition, but averaging 30–40 mole per cent Fe₂SiO₄), with accessory pigeonite and sulfide minerals, and have a density about 3.4.The carbonaceous material and combined water in these meteorites are clearly of extraterrestrial origin, but their significance is not well understood. A biological origin has been claimed for some of the organic compounds on the basis of their composition, but this claim is the subject of considerable dispute. Microscopic objects with regular outline (organized elements) have been recognized in some of these meteorites; some investigators have claimed these to be extraterrestrial fossils, others have ascribed them to terrestrial contamination or considered them to be crystals or crystal aggregates of non-biological origin.     

Assessment of modified surface temperatures and solar reflectance using meteorological satellite and aircraft data

Changes in surface temperature resulting from the activities of man are evaluated using meteorological satellite (NOAA and HCMM) and aircraft data. Study sites were located in Florida and Michigan. Thermal data showed that day surface temperatures over large areas could be increased by 10–15°C by modifications resulting from agricultural practices. Changes in reflected solar radiation as a function of agricultural practices were detectable using HCMM data.     

A proportional counter/image intensifier system for the detection of low energy X-rays

Proportional counters (PC's) and gas scintillation proportional counters (GSPC's) currently used for detection of low energy X-rays provide information on event position and energy. Although at 1.5 keV PC's have good position resolution (～ 200 μm FWHM) they have relatively poor energy resolution (～ 40% FWHM). Conversely GSPC's have reasonable energy resolution (～ 20% FWHM), but poor spatial resolution (～ 1mm FWHM).We describe a scheme in which a parallel plate PC with a transparent anode deposited on a fibre optic substrate has been used. This allows the light emitted by electron avalanches caused by X-ray events in the PC to be detected by an image intensifier with electronic readout. Using this scheme spatial resolution better than that of conventional PC's should be attainable. In addition avalanches induced by single electrons can be resolved through observation of the time structure of the light flash. Using the ability to count the number of primary electrons created by each X-ray event, it is shown that energy resolution can be achieved which is comparable to that of the GSPC.     

X-ray emission from cataclysmic variables

EXOSAT results on cataclysmic variables are reviewed. The long continuous X-ray observations afforded by this observatory, coupled with the sensitivity of its instruments to medium energy and very low energy X-rays, have enabled the rotational and orbital X-ray light curves of these stars to be measured in unprecedented detail. Examples are given of data on synchronously and asynchronously rotating magnetic systems, and on disc accreting stars. The impact of the new observations on our understanding of cataclysmic variables is discussed.     

An EXOSAT observation of the peculiar X-ray binary 2S 0921-630 during optical eclipse

An x-ray observation of 2S 0921-630 has been made coincident with the time of optical eclipse of this 9-day binary. No significant reduction in X-ray flux is measured. This can be explained if the binary orbit is viewed almost exactly edge-on, so that the central X-ray emitting star is obscured by the accretion disk from direct view. The X-rays that are seen are scattered into the line of sight by material above and below the disk and the apparent size of the X-ray emission region is thus large compared to the size of the occulting star.