Classical theories of turbulence do not describe accurately inertial range scaling laws in turbulent convection and notably fail to model the shape of the turbulent spectrum of solar photospheric convection. To understand these discrepancies, a detailed study of scale-by-scale budgets in turbulent Rayleigh-Bénard convection is presented, with particular emphasis placed on anisotropy and inhomogeneity. A generalized Kolmogorov equation applying to convection is derived and its various terms are computed using numerical simulations of turbulent Boussinesq convection. The analysis of the isotropic part of the equation shows that the third-order velocity structure function is significantly affected by buoyancy forcing and large-scale inhomogeneities. Anisotropic contributions to this equation are also shown to be comparable to their isotropic counterpart at moderate to large scales. Implications of these results for convection in the solar photosphere, mesogranulation and supergranulation are discussed.

High-time-resolution X-ray observations of compact objects provide direct access to strong-field gravity, black-hole masses and spins, and the equation of state of ultra-dense matter. LOFT, the Large Observatory for Xray Timing, is specifically designed to study the very rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars. A 10-m2-class instrument in combination with good spectral resolution (<260 eV @ 6 keV) is required to exploit the relevant diagnostics, and has the potential of revolutionising the study of collapsed objects in our Galaxy and of the brightest supermassive black holes in active galactic nuclei. LOFT will carry two main instruments: a Large Area Detector (LAD), to be built at MSSL/UCL in collaboration with the Leicester Space Research Centre, and a Wide Field Monitor (WFM). The ground-breaking characteristic of the LAD (it will work in the energy range 2–30 keV) is a mass per unit surface in the range ~10 kg/m2, giving an effective area of ~10 m2 (@10 keV) at a reasonable weight—an improvement by ~20 over all predecessors. This will allow timing measurements of unprecedented sensitivity, providing the capability to measure the mass and radius of neutron stars with ~5% accuracy, or to reveal blobs orbiting close to the marginally stable orbit in active galactic nuclei. We summarise the characteristics of the LOFT instruments and give an overview of its expected capabilities.

The review examines recent observational and theoretical results on the nonradial pulsation of δ Scuti stars. The dominant pulsation modes are rotationally split p modes with = 1 and 2, and radial orders 1 to 4. Line-profile analyses also reveal the existence of additional high-degree modes. Nonradial pulsation is usually accompanied by slow amplitude and period variability. The small-amplitude single-mode variables are shown to be typical nonradial pulsators.

The interesting cases of 1 Mon and θ2 Tau are examined in more detail. The present status of asteroseismolgy of the δ Scuti stars is reviewed.

The periods of the four evolved δ Scuti variables studied are found to be decreasing, although stellar evolution predicts period increases due to larger radii. New work on the multiple periods of AI Vel shows that, apart from stellar evolution, an additional mechanism must exist to cause temporary period changes. It is argued that for a larger sample of stars the average period change must nevertheless reflect evolutionary changes.

Large scale (19 arc sec/mm), deeply exposed photographs (26.5 mag/sq arc sec) of a sample of 12 QSO's over the redshift range, z = 0.158 to 0.528 have been obtained. Baked IIIa-F plates were used at the prime focus of the ESO 3.6-m telescope. The band pass was 5700–6900A. Logarithmic intensity contour maps and logarithmic image profiles were constructed from PDS microdensitometer scans. Seven of the 12 QSO's show extended (5–10 arc sec), asymmetric structure on the contour maps; while 9 of 12 QSO's show broader image profiles than stars of the same magnitude. The intensity contour maps provide two essential bits of information for follow-up spectroscopy: 1) a guide for locating the slit aperture and 2) a means of estimating integration times.

B[e] supergiants show evidence for a non-spherical two-component stellar wind. The general appearance and the physical properties of the suggested disk-like configuration are discussed. The high mass-loss rates, the surprisingly large number and the location in the H-R diagram make these stars important for the understanding of the post-main-sequence evolution of massive stars.

Using Hipparcos and Tycho-2 data, together with the radial velocity information, a statistical analysis is applied to all the orbital solutions of planetary candidates, in order to avoid a bias towards small inclinations. There are hints of additional, longer period companions.

We have observed 3 moderate redshift clusters using a combination of 7 intermediate band filters and 2 CCDs in order to derive photometric information for cluster galaxies from 400 nm to 900 nm. Preliminary results are presented for 2 clusters: Abell 1942 (z=0.224) and Abell 1525 (z=0.259) from 580 nm to 860 nm. The CCD photometry reaches a limit equivalent to RF=21 mag with a precision of better than 0.1 mag. The galaxy colours derived from the intermediate band measurements are generally consistent with those expected at the appropriate redshift. However, in Abell 1525, and to a lesser extent in Abell 1942, a large proportion of cluster members have far red (720–860 nm) colours redder than expected. Many of these galaxies have blue photographic BJ-RF colours. A possible explanation for the anomalous CCD colours is that these galaxies possess a strong emission line component which enters the far red filter at z=0.25.

In 1964 a conference was held at Flagstaff, Arizona, in honour of Ejnar Hertzsprung. At this conference Martin Schwarzschild presented the inaugural address. The title was ‘New Impetus to Astrometry’. I was so much impressed by everything what he, as an astrophysicist, had to say that I have always remembered his analysis of important astrometric problems with admiration. Nine years after the Flagstaff Conference, I find it appropriate to open this Symposium in referring to Schwarzschild's lecture and in presenting my views on recent developments and on progress which I expect in the future.

Over the past decade, we have come to realize that mass loss on the asymptotic giant branch (AGB) plays a significant role in the formation of planetary nebulae (PN). Mass ejected during the AGB can now be observed in haloes of PN and we believe that the main shell of PN is formed by the interaction of this material with a later-developed central-star wind. In this review, we show that the evolution from AGB to PN can be traced in a continuous infrared sequence. This sequence predicts properties of proto-PN which allow them to be identified.

Observations of the night-sky brightness were organized at 106 places in Japan by a promotion of the Environmental Agency with the help of many local governments. Two kinds of measurements were carried out: 1) Number of stars were counted in a region of triangle formed by Alpha Lyr, Epsilon Lyr, and Zeta Lyr by at least 10 contributors at each point. 2) Photographs of a star field at the zenith at each point were taken with the same type of camera and film. These results gave us a good idea on distribution of night-sky brightness in Japan.

Establishing the role of active galactic nuclei (AGN) during the formation of galaxies remains one of the greatest challenges of galaxy formation theory. Towards addressing this, we summarise our recent work investigating: (1) the physical drivers of ionised outflows and (2) observational signatures of the impact by jets/outflows on star formation and molecular gas content in AGN host galaxies. We confirm a connection between radio emission and extreme ionised gas kinematics in AGN hosts. Emission-line selected AGN are significantly more likely to exhibit ionised outflows (as traced by the [O iii] emission line) if the projected linear extent of the radio emission is confined within the spectroscopic aperture. Follow-up high resolution radio observations and integral field spectroscopy of 10 luminous Type 2 AGN reveal moderate power, young (or frustrated) jets interacting with the interstellar medium. We find that these sources live in highly star forming and gas rich galaxies. Additionally, by combining ALMA-derived dust maps with integral field spectroscopy for eight host galaxies of z ≈ 2 X-ray AGN, we show that Hα emission is an unreliable tracer of star formation. For the five targets with ionised outflows we find no dramatic in-situ shut down of the star formation. Across both of these studies we find that if these AGN do have a negative impact upon their host galaxies, it must be happening on small (unresolved) spatial scales and/or an observable galaxy-wide impact has yet to occur.

Bars are strong drivers of secular evolution in disk galaxies. Bars themselves can evolve secularly through angular momentum transport, producing different boxy/peanut and X-shaped bulges. Our Milky Way is an example of a barred galaxy with a boxy bulge. We present a self-consistent N-body simulation of a barred galaxy which matches remarkably well the structure of the inner Milky Way deduced from star counts. In particular, features taken as signatures of a second “long bar“ can be explained by the interaction between the bar and the spiral arms of the galaxy (Martinez-Valpuesta & Gerhard 2011). Furthermore the structural change in the bulge inside l = 4° measured recently from VVV data can be explained by the high-density near-axisymmetric part of the inner boxy bulge (Gerhard & Martinez-Valpuesta 2012). We also compare this model with kinematic data from recent spectroscopic surveys. We use a modified version of the NMAGIC code (de Lorenzi et al. 2007) to study the properties of the Milky Way bar, obtaining an upper limit for the pattern speed of ~ 42 km/sec/kpc. See Fig. 1 for a comparison of one of our best models with BRAVA data (Kunder et al. 2012).

The subject of interstellar matter is one of the most active fields of astronomical research to-day. Observational information spans the full electromagnetic spectrum from long radio waves to gamma rays and includes cosmic-ray particles. Results of chemical research find as much application now as mathematical methods. Interstellar matter plays a leading role in galactic and extragalactic research, and contributes increasingly to stellar astronomy and in solar system studies.

We present preliminary results of an analysis of X-ray and optical data of the asynchronous AM Her star BY Cam [1]. We use X-ray data from EXOSAT (0.1… 50 keV), Ginga (1.5… 50 keV) and ROSAT (0.1…2.0 keV) and optical data obtained during a 45-day campaign in 1994.

There are 4 known periods: the orbital period (201.30 m), the spin period of the white dwarf (199.3303 m), a spin-orbit beat period (14.15 d) and a side-band period (197.4 m). The detection of this side-band period lends credence to the theory of [2], who suggest that for a stream accreting, diskless, magnetic CV a frequency, f = 2ωspin − Ωorb (=197.399 m), will appear as a strong spike in the power spectrum for certain systems. Wu & Mason (this volume) discuss a competing model where Pspin = 197.4 m.

In the present-day universe, the global properties of bulges and early-type galaxies correlate with the mass of their central black holes, indicating a connection between galaxy evolution and nuclear activity. Understanding the origin of this relation is a major challenge for cosmological models. Using Keck spectra and HST images, we present direct measurements of the correlations between black hole mass and host spheroid luminosity and velocity dispersion at z=0.36, showing that the relations evolved significantly in the past 4 billion years. It appears that black holes of a few 108 M⊙ completed their growth before their host galaxies, and that the current scaling relations are only the final point of the co-evolution of galaxies and black holes.

The collisional ionization of atomic systems by structureless charged particles of arbitrary mass and charge is considered. For the theoretical study, the classical impulse approximation is used. In this case, analytical expressions Q for the ionization cross-sections are given by Garcia et al. (1968). From these expressions, a reduced cross-section QR is obtained as a function of a scaled energy X. It is found that, for a particle of mass M, charge Z, and energy E, incident on a target having ξ equivalent electrons with a binding energy I, QR is given by:

where

IH is the hydrogen ionization potential and me is the electron mass.

The stability of the three-body problem formed by the Sun, Jupiter and Saturn is investigated using surfaces of zero velocity. The results obtained with the models of the restricted and general problems of three bodies are compared with numerical integration. The system is found to be stable in the sense that Saturn will neither interrupt the (perturbed) binary orbit of Jupiter around the Sun, nor will it escape from the system. It is shown that the known classical triple stellar systems are “more stable” than the solar system, which in turn is “more stable” than the Earth-Moon system.

We have used archival Chandra-acis observations to search for X-ray emission from WR stars in the Magellanic Clouds (MCs), where the low interstellar absorption and known distances make it easy to compare X-ray luminosities with spectral types and binary status of WR stars. We have detected X-ray emission from ~20 WR stars in the MCs with X-ray luminosities of 6.6×1032-1.4×1035 ergs s–1. The analysis of the X-ray spectra of the brightest sources indicates that the X-ray emitting gas has temperatures ≥ 1.0×107 K, as expected in colliding winds. We will compare these results with the binary status of the WR stars to determine the amounts of the X-ray emission produced in the colliding winds for WR stars in binary systems and to assess the X-ray emission from single WR stars.

Galactic D/H evaluations from observations completed in the far UV with first the Copernicus satellite then followed by IUE and the GHRS on the HST studies already suggest that D/H variations may be present in the interstellar medium. More recent IMAPS (the Interstellar Medium Absorption Profile Spectrograph) observations confirm that conclusion while new STIS (which replaced the GHRS on board HST) studies seem to indicate the contrary. The situation is discussed here.

Hopefully FUSE (the Far Ultraviolet Spectroscopic Explorer, launched the 24th of June 1999) will give access to the D/H ratio in many different galactic sites. This will help us reach a better global view of the evolution of that key element, and thus better constrain any evaluation of its primordial abundance.