Ultraviolet Astronomy: Astrophysical Perspectives of the Spektr-UF Project (WSO-UV)

Astrophysics - The prospects for astronomical observations in the ultraviolet (UV) are discussed in a brief review and the areas in which UV astronomy is especially in demand are listed. Some...     

Galactic structure from the Two Micron Galactic Survey

The Two Micron Galactic Survey (TMGS) is the most sensitive large scale point source near infrared survey of the Galactic Plane yet attempted. The Galactic plane has been drift-scanned in several regions over the areas -5° <l < 30°, |b | 15° and 30° <l < 180°, |b | 5°. The survey is complete in the areas covered to magnitudem _k = +9.8. So far, a total area of 255 square degrees has been mapped and 500000 objects have been detected, the majority of these in the Galactic plane and with no visible counterparts. In this contribution we use data from the TMGS to probe the star distribution within the Galactic disk.     

Astronomy in the Elbrus Region

Astronomical research in the Elbrus Region are conducted in the wide international cooperation. They are implemented in under the aegis of the International Association of Academies of Sciences in collaboration with the Euro-Asiatic Association of Universities. Authors outline the important scientific results obtained in the fields of fundamental, applied, and search studies within the international astronomical programs at the Terskol Peak Observatory. They refer to the problem of the identification of diffuse interstellar bands, studies of the star light-curve, detection of optical residuals of gamma-ray bursts, determination of the kinematic and physical characteristics of minor bodies of the Solar System (asteroids and comets), as well as investigation of space objects of technogenic origin in the near-Earth space environment.     

Galactic Fountains and Galactic Winds

The development of galactic fountain theories is reviewed with special emphasis on the different approaches and concepts that have been used in the past. In particular the outstanding contribution of Franz Kahn to our physical understanding is appreciated. It is argued that galactic outflows represent an essential phase during galaxy evolution. The dynamics of the outflow imprints its signature on the emission spectra of soft X-rays, which may well be observable with AXAF and XMM. Finally, some remarks about winds in starburst galaxies and AGN are made. This revised version was published online in July 2006 with corrections to the Cover Date.     

Astronomy in Antarctica

Antarctica provides a unique environment for astronomers to practice their trade. The cold, dry and stable air found above the high Antarctic plateau, as well as the pure ice below, offers new opportunities for the conduct of observational astronomy across both the photon and the particle spectrum. The summits of the Antarctic plateau provide the best seeing conditions, the darkest skies and the most transparent atmosphere of any earth-based observing site. Astronomical activities are now underway at four plateau sites: the Amundsen-Scott South Pole Station, Concordia Station at Dome C, Kunlun Station at Dome A and Fuji Station at Dome F, in addition to long duration ballooning from the coastal station of McMurdo, at stations run by the USA, France/Italy, China, Japan and the USA, respectively. The astronomy conducted from Antarctica includes optical, infrared, terahertz and sub-millimetre astronomy, measurements of cosmic microwave background anisotropies, solar astronomy, as well as high energy astrophysics involving the measurement of cosmic rays, gamma rays and neutrinos. Antarctica is also the richest source of meteorites on our planet. An extensive range of site testing measurements have been made over the high plateau sites. In this article, we summarise the facets of Antarctica that are driving developments in astronomy there, and review the results of the site testing experiments undertaken to quantify those characteristics of the Antarctic plateau relevant for astronomical observation. We also outline the historical development of the astronomy on the continent, and then review the principal scientific results to have emerged over the past three decades of activity in the discipline. These range from determination of the dominant frequencies of the 5 min solar oscillation in 1979 to the highest angular scale measurements yet made of the power spectrum of the CMBR anisotropies in 2010. They span through infrared views of the galactic ecology in star formation complexes in 1999, the first clear demonstration that the Universe was flat in 2000, the first detection of polarization in the CMBR in 2002, the mapping of the warm molecular gas across the ~ 300 pc extent of the Central Molecular Zone of our Galaxy in 2003, the measurement of cosmic neutrinos in 2005, and imaging of the thermal Sunyaev Zel’dovich effect in galaxy clusters in 2008. This review also discusses how science is conducted in Antarctica, and in particular the difficulties, as well as the advantages, faced by astronomers seeking to bring their experiments there. It also reviews some of the political issues that will be encountered, both at national and international level. Finally, the review discusses where Antarctic astronomy may be heading in the coming decade, in particular plans for infrared and terahertz astronomy, including the new facilities being considered for these wavebands at the high plateau stations.     

Astronomy in Japan

The research activity in Japanese astronomy is described, taking into account the social and historical background. A trend in the last two decades is shown by the numbers of papers in 13 branches of astronomy. Major research facilities and international collaboration programs are summerized. Future programs under consideration are briefly discussed.Paper presented at the Lembang-Bamberg IAU Colloquium No. 80 on Double Stars: Physical Properties and Generic Relations, held at Bandung, Indonesia, 3–7 June, 1983.     

Astronomy in Tadjikistan

The astronomical investigations in the present Tadjikistan (USSR) are carried out by the Institute of Astrophysics of the Academy of Sciences of Tadjik SSR. The main scientific fields of investigation are meteors, comets, and variable stars. The Institute has two observational stations: the Gissar observatory with photographic and radar meteor patrols, a 70 cm telescope, a 40 cm Zeiss astrograph, etc., and the Sanglok observatory with the Ritchey-Chrétien 1 m telescope.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.     

Women in the History of Astronomy

We think about the History of Astronomy as the History of men. As the History of a few men: Ptolemy, Copernicus, Kepler, Newton,...- men who have changed our way of looking at the sky. But the History of Astronomy is more than that, it is the History of thousand of people whose daily work has allowed the development of knowledge and scientific theories at the time they lived. This, sometimes, "tedious work" permitted the big steps. Many of these people were women, as Theano who married Pythagoras and taught mathematics and astronomy in his school, Hypatia who managed the Library of Alexandria and wrote several astronomical treatises, Hildegard of Bingen who developed a theory on the origin and structure of the Universe in the 12^th century, or Sofie Brahe who, worked with her famous brother. And so many privileged women who after a long process of study, were able to develop their scientific interests in spite of been excluded from most of the educational installations and formal and informal groups of men scientist. Most of the works done by these women have been ignored, or wrongly attributed to men throughout History. It often happens that although they have been recognized as good scientists in their own times, women have been discredited by posterior historians who refused to believe that important women scientist ever existed. Here we intend to make a short summary on the lives of some of these women and their astronomical works. This revised version was published online in July 2006 with corrections to the Cover Date.     

Galactic nuclei

Application of standard accretion-disk theory to the central parts of galactic disks implies that galactic nuclei should pass quasi-periodically through stages of (i) gravitational instability (Starburst), (ii) non-thermal disk activity (LINER), and (iii) central-plane nuclear burning (AGN). Nuclear disks can have large mass-to-light ratios, and store large masses at high (Keplerian) rotation velocities. Aburning disk can explain all the phenomena commonly attributed to a supermassive Black Hole.     

Metallic Particles in Astronomy

We discuss some implications of iron whiskers condensing in supernova ejecta and being expelled into interstellar and intergalactic space. The supposition that the universal microwave background is a relic from an early hot state of the Universe is shown to be not as secure as is commonly supposed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Galactic wind

We discussed the possible role of active galactic nuclei, which would lead to the generation of strong winds from them. We show that the galaxies are swept clean of hot gases from dying stars by such winds, resulting in the observed upper limit in the gas-content of E and SO galaxies.     

Galactic bulges

We model the evolution of the Galactic bulge and of the bulges of a selected sample of external spiral galaxies, via the multiphase multizone evolution model. We address a few questions concerning the role of the bulges within galactic evolution schemes and the properties of bulge stellar populations. We provide solutions to the problems of chemical abundances and spectral indices, the two main observational constraints to bulge structure.     

Galactic fountains

The hot intercloud medium (ICM) streams away from the Galactic disk into the fountain. It is generally agreed that a flow consisting of thermal gas only reaches a maximum height of a few (3 to 5) kpc. The dynamics is more complicated if cosmic rays are also present. In that case it is possible for some of the gas to be ejected from the Galaxy altogether.     

Building the Fast Galactic Dynamo

In this paper we demonstrate the importance of cosmic rays for the dynamics of the interstellar medium. We present the first 3D-MHD numerical simulations of the Parker instability triggered by cosmic rays accelerated in randomly distributed supernova remnants. We show that in the presence of galactic rotation a net radial magnetic field is produced as a result of the cosmic ray injection and Coriolis force. This process provides a possibility of very efficient magnetic field amplification within the general frame of so called fast galactic dynamo proposed by Parker (1992).     

Galactic oscillations

A stable galaxy, if excited above its ground state, oscillates about that ground state. If it is reasonably robust, it can support oscillations of large amplitude. Normal mode oscillations, with surprisingly large amplitudes, have been seen in numerical experiments. Observational evidence shows that real galaxies also oscillate. Galaxies ring like a bell in the experiments, and ringing continues undamped long after initial transients have died out. Their total kinetic energy oscillates with an amplitude as large as 10% of the mean. A fundamental mode dominates. It is an homologous expansion/contraction of the entire galaxy (no nodes). Inward or outward velocities due to this mode are sufficiently large in the outer reaches of a galaxy to account for kinematic warps in observed velocity fields. A second spherically symmetrical mode has one node and is important near the center of the galaxy. It may be the driving force behind bulges in spiral galaxies. Two other normal modes have been identified as well. This appears to be the first experimental demonstration of normal mode oscillations within stable galaxy models.