The HI envelope of the Magellanic System extends well beyond the obvious visible regions of each of the Clouds. Modern optical surveys based on UK Schmidt telescope plates and fast measuring machines are now starting to reveal the complex optical counterparts of some of these HI features.

In this contribution I will present some results of a program aimed at determining the optical variability characteristics of Seyfert galaxy nuclei. It has been known for more than a decade that the continuous, non-stellar light of Seyfert nuclei can vary significantly on a time scale of months to years (see, e.g., Lyutyi, 1973, 1977; Penston et al., 1974; Penfold, 1979). In recent years there also have been various reports of variations in the intensity of the broad optical emission lines (Boksenberg and Netzer, 1977; Tohline and Osterbrock, 1976) following the pioneering work by Souffrin et al. (1973) and Cherepashchuk and Lyutyi (1973). However, very little is known on the details of the continuum variations and how they relate to the line variability. Such information could provide valuable constraints on the fashionable photo-ionization models for the broad line region (BLR) and the structure of the latter.

The structure of bulges and ellipticals, and their relation to galaxy halos are reviewed. Since many ellipticals contain faint disks, the qualitative distinction between bulges and ellipticals is more accurately described as a quantitative variation in Bulge/Disk ratio. The exception may be the brightest ellipticals, which are usually Bright (est) Cluster Members. The available evidence suggests that the spheroid properties are determined by more than halo properties alone. This is clearest for systems with low B/D ratio, where bulge velocity dispersions are similar to disk velocity dispersions. Constraints on the stellar formation scenarios are discussed.

Two separate Balmer jumps are observed in some Be stars. The first one, in absorption and unchanging, is attributed to the central star and gives its spectral type and luminosity class in the λ,D system. The second one, occuring at shorter wavelengths, either in absorption or in emission, originates in layers at a low pressure. It is shown that these layers modify the colors of the central star on both sides of the Balmer jump and that they are not optically thin even in the continuum.

Kuhn & Miller (1989, KM hereafter) proposed that a small stellar system in orbit around a large galaxy could be heated through resonant coupling between the orbital motion and internal modes of oscillation of the satellite. They further argued that the apparently large mass-to-light (M/L) ratios of dwarf spheroidal (dSph) galaxies around the Milky Way (e.g., Armandroff, Olszewski & Pryor 1995) could be illusory because the satellites are far from virial equilibrium as a consequence of such resonant heating. We note that if the true M/Ls are small, some dSphs have much more kinetic energy than is required to unbind them; a resonant pumping mechanism which adds a modest amount of energy each cycle could not achieve this (Pryor 1996).

Results from Lunar Laser Ranging data analysis are presented: (a) the values and statistics of UT1 determined by three stations are given; (b) the lunar tidal acceleration n is found to be −24.9 ± 1.0 arc sec/century2; (c) the tidal-effect coefficient k/C for UT1 is shown to be in strong agreement with the theoretical value; and (d) corrections to the IAU values of precession and nutation are estimated.

The participants in this meeting are almost all carrying out the hard work of making many different types of AGN surveys. Since it’s so much easier to criticize other people’s work than to do actual work myself, I’ll just present some demurs regarding recent papers drawing conclusions from various AGN survey data. In particular I’ll mention some questionable interpretations of surveys of Seyfert 2 near-UV polarization; interpreting the results of searches for polarized broad H-alpha lines in Seyfert 2s; testing the beam model for radio galaxies and quasars; testing the unification of Seyfert spectral types with a torus; and finally testing the energy sources for ULIRGs, especially those with LINER optical spectra. Only the polarized broad H-α results are examined in detail here.

Coronal disturbances are considered as consequences of the ejection of electric currents (or non-potential magnetic fields) from the photosphere and chromosphere into the corona. It may be that electric currents are generated near neutral lines in the photosphere and are later ejected into the corona.

Centrifugally driven winds from the surfaces of magnetized accretion disks are an attractive mechanism for removing the angular momentum of the accreted matter and of producing bipolar outflows and jets in compact astronomical objects. In this contribution, I first review steady–state disk–wind models that have been constructed for the different density regimes of circumstellar disks and comment on their expected stability. I then consider several nonsteady effects, including disk formation in molecular cloud-core collapse, magnetic flux transport through the disk, and the role of magnetic fields in the FU Orionis outburst phenomenon. I conclude with a discussion of some of the unique observational properties of disk-driven outflows in young stellar objects and in active galactic nuclei. These characteristics are a consequence of the highly stratified density and velocity structures of centrifugally driven outflows, their large momentum discharges (which result in the efficient uplifting of dust from the disk), and, in the case of molecular disks around lowluminosity objects, their comparatively low initial degrees of ionization (which can lead to rapid heating by ambipolar diffusion).

The H92α recombination line was observed at 8 GHz toward the “pistol-shaped” HII region G0.15–0.05 using the VLA2 in its most compact configuration. The line profiles of individual components of this source peak at VLSR=123 km/s and have total line widths of ~90 km/s. The kinematical structure of the “pistol” is unusual in that much of the neutral and ionized gas in this region is seen predominantly at either +50 or +20 km/s. The line width and radial velocity are the largest found in the Galactic center region with the exception of Sgr A West. We also found gas at VLSR=140 km/s associated with G0.18–0.04: the sickle-shaped feature which surrounds G0.15–0.05. The kinematic properties of G0.18–0.04 and G0.15–0.05 suggest that these two features are components of a single, but complex thermal system interacting with the nonthermal filaments of the radio Arc. In this regard, the width of the broad recombination line from G0.15–0.05, and its large radial velocity, might be explained as the interaction of streaming relativistic particles in the nonthermal filaments of the Arc impacting upon ambient gas clouds lying in the Galactic plane.

Four meteor spectra from the NASA LRC Faint Meteor Spectra Patrol are analyzed for chemical composition and radiative processes. The chemical compositions of the Taurid, Geminid, and Perseid meteors were found to be similar to that of a typical stony meteorite. The chemical composition of the sporadic meteor was found to be similar to that of a nickel-iron meteorite. The radiation from optical meteors (+ 1 to —10 absolute photographic magnitude) was found to be similar to that of a low-temperature gas, except that strong, anomalous ionic radiation is superposed on the neutral radiation in bright (< — 3 mag), fast meteors.

We discuss the importance of accretion in calculating disk models for young stellar objects. In particular, we show that a disk inner rim, irradiated by both the star and the accretion shocks at the stellar surface, can naturally explain recent observations of DG Tau with the Keck interferometer. We present models for two objects, with mass accretion rates differing by almost two orders of magnitude, to illustrate the effects of accretion on the overall disk structure and emission.

Massive stars are rapid rotators. Equatorial rotation velocities span the range vrot = 100–400 km s−1, with B stars rotating closest to their break-up speed vcrit (Howarth et al. 1997). During the last decade, many observations have revealed unusual surface abundances that may require additional internal mixing (beyond that of simple convection and overshooting) for their explanation, most important helium and nitrogen enrichment in main sequence O and B stars (Gies & Lambert 1992), in the SN 1987A progenitor (Fransson et al. 1989), and boron depletions in main sequence B stars (Venn et al. 1996). In particular the latter observations clearly point towards internal mixing and rule out a close binary origin of the abundance peculiarities (Fliegner et al. 1996). Altogether, the occurrence of some form of additional mixing responsible for altering the surface abundances in a large fraction, if not all massive stars appears to be beyond reasonable doubt, and mixing processes due to rotation are the most natural explanation.

Diffuse background radiation is integrated light which is consisted of various components of interplanetary, stellar, interstellar, galactic and intergalactic origins as well as cosmic background radiation, the remnant of the pre-galactic phenomena in the early history of the universe.

As Supernova remnants expand, their shock waves are freezing in and compressing the magnetic field lines they encounter; consequently we can use Supernova remnants as magnifying glasses for their ambient magnetic fields. We will describe a simple model to determine emission, polarization, and rotation measure characteristics of adiabatically expanding Supernova remnants and how we can exploit this model to gain information about the large scale magnetic field in our Galaxy. We will give two examples: The SNR DA530, which is located high above the Galactic plane, reveals information about the magnetic field in the halo of our Galaxy. The SNR G182.4+4.3 is located close to the anti-centre of our Galaxy and reveals the most probable direction where the large-scale magnetic field is perpendicular to the line of sight. This may help to decide on the large-scale magnetic field configuration of our Galaxy. But more observations of SNRs are needed.

Analysis of sky images obtained from an automated experiment at Dome C, Antarctica, at 2-hourly intervals from February to November 2001 show cloud-free conditions 74% of the time. This augurs well for the prospects of future astronomical observatories at this site.

Gaia is ESA's upcoming astrometry mission, building on the heritage of its predecessor, Hipparcos. The Gaia nominal scanning law (NSL) prescribes the ideal attitude of the spacecraft over the operational phase of the mission. As such, it precisely determines when certain areas of the sky are observed. From theoretical considerations on sky-sampling uniformity, it is easy to show that the optimum scanning law for a space astrometry experiment like Gaia is a revolving scan with uniform rotation around the instrument symmetry axis. Since thermal stability requirements for Gaia's payload require the solar aspect angle to be fixed, the optimum parallax resolving power is obtained by letting the spin axis precess around the solar direction. The precession speed has been selected as compromise, limiting the across-scan smearing of images when they transit the focal plane, providing sufficient overlap between successive “great-circle” scans of the fields of view, and guaranteeing overlap of successive precession loops. With this scanning law, with fixed solar-aspect angle, spin rate, and precession speed, only two free parameters remain: the initial spin phase and the initial precession angle, at the start of science operations. Both angles, and in particular the initial precession angle, can be initialized following various (programmatic) criteria. Examples are optimization/fine-tuning of the Earth-pointing angle, of the number and total duration of Galactic-plane scans, or of the ground-station scheduling. This paper explores various criteria, with particular emphasis on the opportunity to optimise the scanning-law initial conditions to “observe” the most favorable passages of bright stars very close to Jupiter's limb. This would allow a unique determination of the light deflection due to the quadrupole component of the gravitational field of this planet.

A linked submillimeter-wave interferometer using the CSO 10.4 m and the JCMT 15 m telescopes located on Mauna Kea at an elevation of 4200 m, has been built and tested successfully. The capabilities of the instrument and an outline of the type of observations that can be made with a single, fixed-baseline interferometer are given. In particular, an experiment to detect gas infalling onto low-mass protostellar sources is proposed. The design of the instrument is described briefly and the successful results of the first tests are summarized.

Results of the Deep Impact mission to impact Comet Tempel 1 are summarized.

The current status of modelling the wind driving mechanism of AGB stars is reviewed. Our present understanding of these winds is substantially guided by spherically symmetric, time-dependent models which reveal a complex interplay between stellar pulsation, hydrodynamics, small-scale waves, chemistry, dust formation and radiative transfer. The level of approximation used for the physical description of the various processes, and the degree of consistence in the models are crucial and different approaches lead to rather different results. Beside reviewing the frontiers of the present theoretical research on AGB star winds, this paper presents some new results concerning the cooling of the gas behind propagating shock waves in the outer atmosphere and the self-organisation of dust-forming gases (cloud formation) caused by a radiative/thermal instability of dust forming gases.