SOLAR-A reformatted data files and observing log

All of the SOLAR-A telemetry data will be reformatted before distribution to the analysis computers and the various users. This paper gives an overview of the files which will be created and the format and organization which the files will use. The organization has been chosen to be efficient in space, to ease access to the data, and to allow for the data to be transportable to different machines. An observing log file will be created automatically using the reformatted data files as the input. It will be possible to perform searches with the observing log to list cases where instruments are in certain modes and/or seeing certain signal levels.After the launch the name of SOLAR-A has been changed to YOHKOH.     

Digitization and Scientific Exploitation of the Italian and Vatican Astronomical Plate Archives

There is a widespread interest to digitize the precious information contained in the astronomical plate archives, both for the preservation of their content and for its fast distribution to all interested researchers in order to achieve their better scientific exploitation. This paper presents the first results of our large-scale project to digitize the archive of plates of the Italian Astronomical Observatories and of the Specola Vaticana. Similar systems, composed by commercial flat-bed retro-illuminated scanners plus dedicated personal computers and acquisition and analysis software, have been installed in all participating Institutes. Ad-hoc codes have been developed to acquire the data, to test the suitability of the machines to our scientific needs, and to reduce the digital data in order to extract the astrometric, photometric and spectroscopic content. Two more elements complete the overall project: the provision of high quality BVRI CCD sequences in selected fields with the Campo Imperatore telescopes, and the distribution of the digitized information to all interested researchers via the Web. The methods we have derived in the course of this project have been already applied successfully to plates taken by other Observatories, for instance at Byurakan and at Hamburg.     

The effect of massive binaries on stellar populations and supernova progenitors

We compare our latest single and binary stellar model results from the Cambridge stars code to several sets of observations. We examine four stellar population ratios: the number of blue to red supergiants, the number of Wolf–Rayet stars to O supergiants, the number of red supergiants to Wolf–Rayet stars and the relative number of Wolf–Rayet subtypes, WC to WN stars. These four ratios provide a quantitative measure of nuclear burning lifetimes and the importance of mass loss during various stages of the stars' lifetimes. In addition, we compare our models to the relative rate of Type Ib/c to Type II supernovae to measure the amount of mass lost over the entire lives of all stars. We find reasonable agreement between the observationally inferred values and our predicted values by mixing single and binary star populations. However, there is evidence that extra mass loss is required to improve the agreement further, to reduce the number of red supergiants and increase the number of Wolf–Rayet stars.     

Astro-WISE interfaces

From a simple text interface to a graphical user interfaces—Astro-WISE provides the user with a wide range of possibilities to interact with the information system according to the user’s tasks and use cases. We describe a general approach to the interfacing of a scientific information system. We use this approach to create a number of services, which allows the user to browse the data stored in the system, to process the data and to exchange the newly created images and catalogs with the users within the system and wider astronomical community. Reusability of interfaces and services is another important feature of our approach. It reduces the time and resources spent to interface other information systems created from Astro-WISE.     

Fitting the integrated spectral energy distributions of galaxies

Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details of dust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.     

Source rates and ion recycling rates for Na and K in Mercury's atmosphere

The supply rates of Na and K to the atmosphere of Mercury by processes acting on the extreme surface—thermal vaporization, photon-stimulated desorption (PSD), and ion-sputtering—are limited by the rates at which atoms can be supplied to the extreme surface by diffusion from inside the regolith grains. Supply rates to the atmosphere are further regulated by ion retention and by gardening rates that supply new grains to the surface. We consider the limits on supply of sodium and potassium atoms to the atmosphere, and rates of photoion recycling to the surface. Thermal vaporization rates are severely limited by the ability of atoms to diffuse to the surface of the grain. Therefore, the diffusion-limited thermal vaporization rates on Mercury's surface are comparable to or less than the PSD rates. Ion sputtering is primarily due to highly ionized heavy ions, even though they represent a small fraction of the solar wind. We have shown that up to 60% of the Na photoions are deposited on the surface of Mercury. Ion recycling to the surface can have a long-term effect on the regolith abundance if an average recycling pattern persists such that more ions return to a particular area than are launched there. It is unknown whether the formation of latitude bands of >100% ion retention persist on average despite a rapidly changing magnetosphere. The total exospheric column of sodium observed at Mercury between 1997 to 2003 varied by a factor of 2-3 from perihelion to aphelion.     

Possibilities of investigation of interstellar matter by radio recombination lines (Review)

Radio recombination lines (RRL) discovered about 25 years ago became a very effective tool for the investigation of interstellar matter (ISM). These lines are unique by the number of transitions and the spectral range observed: from 2 mm to 20 m wavelength. This allows to study the ISM under variety of physical conditions which differ by 7 to 8 orders of magnitude in density and 3 orders of magnitude in temperature. RRL allow to determine the main physical conditions in HII and HI-CII regions, to map the galactic distribution of ionized hydrogen, and to obtain the helium abundance of the ISM. Furthermore, the information contained in the RRL allows to estimate the intensity of cosmic rays and to draw conclusions on the galactic evolution. The physical properties of the RRL and the results obtained by observations of RRLs are reviewed.     

The Argentinean Patagonia and the Martian landscape

Throughout the Cenozoic Era, the geological history of the Argentinean Patagonia was dominated by basaltic volcanism and glacial and periglacial environments. Several geological and geomorphological processes that concurred to the sculpting of the landscape of this area could have been similar to those responsible of the shaping of the Martian surface. In this work a survey of some high-resolution satellite images of the Argentinean Patagonia is performed in order to identify possible geomorphological analogs of the Martian surface. Several morphologies that resemble Martian features are presented and discussed. They consist of proglacial and periglacial features, relatively small circular depressions, gullies, fan-deltas, eolian streaks, and diluvial dunes. Results suggest that the Argentinean Patagonia appears to consist of an interesting terrestrial analog for the Martian landscape. Furthermore, the study area shows to be interesting in order to test robotic instruments and human missions equipment, to train astronauts of future human expeditions to Mars, and to perform astrobiological experiments.     

Light-time computations for the BepiColombo Radio Science Experiment

The Radio Science Experiment is one of the on board experiments of the Mercury ESA mission BepiColombo that will be launched in 2014. The goals of the experiment are to determine the gravity field of Mercury and its rotation state, to determine the orbit of Mercury, to constrain the possible theories of gravitation (for example by determining the post-Newtonian parameters), to provide the spacecraft position for geodesy experiments and to contribute to planetary ephemerides improvement. This is possible thanks to a new technology which allows to reach great accuracies in the observables range and range rate; it is well known that a similar level of accuracy requires studying a suitable model taking into account numerous relativistic effects. In this paper we deal with the modelling of the space-time coordinate transformations needed for the light-time computations and the numerical methods adopted to avoid rounding-off errors in such computations.     

Structure through colour: a pixel approach towards understanding galaxies

We present a study of pixel colour–magnitude diagrams (pCMDs) for a sample of 69 nearby galaxies chosen to span a wide range of Hubble types. Our goal is to determine how useful a pixel approach is for studying galaxies according to their stellar light distributions and content. The galaxy images were analysed on a pixel-by-pixel basis to reveal the structure of the individual pCMDs. We find that the average surface brightness (or projected mass density) in each pixel varies according to galaxy type. Early-type galaxies exhibit a clear 'prime sequence' and some pCMDs of face-on spirals reveal 'inverse-L' structures. We find that the colour dispersion at a given magnitude is found to be approximately constant in early-type galaxies but this quantity varies in the mid and late types. We investigate individual galaxies and find that the pCMDs can be used to pick out morphological features. We discuss the discovery of 'Red Hooks' in the pCMDs of six early-type galaxies and two spirals and postulate their origins. We develop quantitative methods to characterize the pCMDs, including measures of the blue-to-red light ratio and colour distributions of each galaxy and we organize these by morphological type. We compare the colours of the pixels in each galaxy with the stellar population models of Bruzual & Charlot to calculate star formation histories for each galaxy type and compare these to the stellar mass within each pixel. Maps of pixel stellar mass and mass-to-light ratio are compared to galaxy images. We apply the pCMD technique to three galaxies in the Hubble Ultra Deep Field to test the usefulness of the analysis at high redshift. We propose that these results can be used as part of a new system of automated classification of galaxies that can be applied at high redshift.     

Newtonian non-linear hydrodynamics and magnetohydrodynamics

We use covariant techniques to study the non-linear evolution of self-gravitating, non-relativistic media. The formalism is first applied to imperfect fluids, aiming at the kinematic effects of viscosity, before extended to inhomogeneous magnetized environments. The non-linear electrodynamic formulae are derived and successively applied to electrically resistive and to highly conductive fluids. By nature, the covariant equations isolate the magnetic effects on the kinematics and the dynamics of the medium, combining mathematical transparency and physical clarity. Employing the Newtonian analogue of the relativistic 1 + 3 covariant treatment also facilitates the direct comparison with the earlier relativistic studies and helps to identify the differences in an unambiguous way. The purpose of this work is to set the framework and take a first step towards the detailed analytical study of complex non-linear systems, like non-relativistic astrophysical plasmas and collapsing protogalactic clouds.     

Back to the future: science and technology directions for radio telescopes of the twenty-first century

The early days of radio astronomy showed incredibly diverse experimentation in ways to sample the electromagnetic spectrum at radio wavelengths. In addition to obtaining adequate sensitivity by building large collection areas, a primary goal also was to achieve sufficient angular resolution to localize radio sources for multi-wavelength identification. This led to many creative designs and the invention of aperture synthesis and VLBI. Some of the basic telescope types remain to the present day, now implemented across the entire radio spectrum from wavelengths of tens of meters to submillimeter wavelengths. In recent years, as always, there is still the drive for greater sensitivity but a primary goal is now to achieve very large fields of view to complement high resolution and frequency coverage, leading to a new phase of experimentation. This is the “back to the future” aspect of current research and development for next-generation radio telescopes. In this paper I summarize the scientific motivations for development of new technology and telescopes since about 1990 and going forward for the next decade and longer. Relevant elements include highly optimized telescope optics and feed antenna designs, innovative fabrication methods for large reflectors and dipole arrays, digital implementations, and hardware vs. software processing. The emphasis will be on meter and centimeter wavelength telescopes but I include a brief discussion of millimeter wavelengths to put the longer wavelength enterprises into perspective. I do not discuss submillimeter wavelengths because they are covered in other papers.     

Cooperation with the SCOSTEP Project: Study of Travelling Interplanetary Phenomena (STIP)

The Flare Build-up Study (FBS) is primarily devoted to the study of various physical processes on the Sun prior to the occurrence of a solar flare. The relationship of these processes to the flare itself is then to be compared to similar, albeit smaller, processes in the magnetosopheric tail sometimes called the auroral flare. The Study of Travelling Interplanetary Phenomena (STIP) is devoted to specific studies of various phenomena from their inception on the Sun to their passage through the interplanetary medium. Some of these studies will be prior to and during both solar flare and magnetospheric substorm phenomena. Various scientific areas where the work of FBS and STIP would be mutually beneficial are discussed.     

Early applications of computer technology to dynamical astronomy

The review traces the progress from the early application of the Hollerith Tabulating Machine to the construction of astronomical tables by interpolation and to the evaluation of Brown's Tables of the Moon by L. J. Comrie in the late 1920's and early 1930's to the introduction of large programmable electronic calculators in the post World War II era. The early application of electromechanical punched-card machines to astronomical problems stemmed from the needs of the national ephemeris offices to evaluate theories of the Sun, Moon and planets and to subtabulate these positions to form the tables of daily values given in the national almanacs. These techniques were quickly applied to other astronomical problems such as the construction of star catalogs, the reduction of astrometric observations and the numerical integration of the equations of motion of objects in the solar system.     

Ozone and the polar hood of Mars

Ozone co-appears with the clouds of the polar hood in the winter hemisphere of Mars, but each is variable from day to day and location.to location. Both the appearance of ozone and the polar hood clouds correlate with the temperature of the atmosphere which varies from day to day and location to location. A cold, clean, dry atmosphere is conducive to the formation of ozone.     

The conditions for the existence of the electric field opposite to the current along the magnetic field lines in the thin plasma

The flow of the current along the magnetic field lines in the thin plasma directed opposite to the electric field is considered. The particles moving to the equatorial plane are supposed to have mirror points above the region of absorption (the ionosphere) and the particles moving to the ionosphere are supposed to have mirror points below the region of absorption. The current, therefore, flows. The functions of the distribution of the electrons and ions are considered to be mono-energetic. The energies of the electrons and the ions and their densities on the boundary of absorption are estimated for the potential difference and for the current density which are typical for the auroral field lines.     

Japanese 0.5 m AND 1.0 m telescopes for near-earth asteroid observations

To make detection andfollow-up observations of near-earth asteroids (NEOs), a new project tobuild 0.5 m and 1.0 m telescopes has been started with a support of theScience and Technology Agency in Japan. These are the first telescopesdesigned from its beginning to dedicate specifically to the NEOobservations and are expected to be one of the most efficient telescopesfor the NEO observations.It is expected to obtain several ten giga-bytedata per one clear night. Such large numbers of data are able to sharewith international groups. These sharing activities will contribute 1)for us to obtain data of asteroid with the lowest level of signal, and2) for those groups to study how to reduce astronomical data.     

The Mars oxidant experiment (MOx) for Mars '96

The MOx instrument was developed to characterize the reactive nature of the martian soil. The objectives of MOx were: (1) to measure the rate of degradation of organics in the martian environment; (2) to determine if the reactions seen by the Viking biology experiments were caused by a soil oxidant and measure the reactivity of the soil and atmosphere: (3) to monitor the degradation, when exposed to the martian environment, of materials of potential use in future missions; and, finally, (4) to develop technologies and approaches that can be part of future soil analysis instrumentation. The basic approach taken in the MOx instrument was to place a variety of materials composed as thin films in contact with the soil and monitor the physical and chemical changes that result. The optical reflectance of the thin films was the primary sensing-mode. Thin films of organic materials, metals, and semiconductors were prepared. Laboratory simulations demonstrated the response of thin films to active oxidants.     

Reminiscing my sixty year pursuit of the physics of the Sun and the Galaxy

Reminiscing begins with childhood and passes on to student days through graduate school and the first real contact with research.Then early academic positions and stumbling efforts to pursue my ideas.The first significant progress came as a research associate with Prof.W.M.Elsasser at the University of Utah,beginning with an introduction to magnetohydrodynamics and the generation of the geomagnetic field through induction in the liquid metal core of Earth.A move to the University of Chicago to work with Prof.J.A.Simpson,on the implications of cosmic ray variations and interplanetary magnetic fields,led to the theory of coronal expansion and the solar wind and then to exploring the dynamical effects of cosmic rays on the galactic magnetic field.Spontaneous current sheets and intrinsic rapid reconnection in interlaced magnetic field line topologies were the next big project,leading up to retirement.Finally,it is a pleasure to recall my many associates,whose fresh thinking helped stimulate the daily research activities.