In this paper I report the results of a survey of the astronomical outputs of all 63 IAU member countries as well as several non-member countries, based on an analysis of the affiliations of the authors given for nearly 900 thousand astronomical papers appearing in ADS between the years 1976 and 2005. The results show a roughly three-fold increase in the number of published papers per year over this 30-year interval. This increase is seen both in developed and also in most developing countries. The number of publications per IAU member correlates strongly with gross domestic product. It is over 2 papers per IAU member per year in the countries with the strongest economies but less than 0.5 in the countries with low GDP per capita. Since 2001 there has been a dramatic increase in the number of multi-author multinational papers published. This increase is especially noticeable for authors in developing countries, indicating that astronomers in these countries are increasingly participating in international collaborations for their research activities.

The goal of this Joint Discussion is to bring together theorists and observers from the stellar and extragalactic communities to discuss the properties of the most massive stars and the implications for cosmological studies. We will focus on a set of themes that follow from fundamental stellar astronomy, such as mass determinations in binary stars, to recent modeling of atmospheres and evolution, to the significance of massive stars for the ecology of the host galaxy, and finally to a critical assessment of the properties of the first generation of stars in the universe.

We make a case for the usefulness of small telescopes astrometry.

We present preliminary results of Hα near-infrared (NIR) spectroscopy of 16 galaxies with redshifts in the range 0.8 ≤ z ≤ 1.0 drawn from the DEEP2 Galaxy Redshift Survey. The spectra were taken using the multi-slit mode of LIRIS (Long-slit Intermediate Resolution Infrared Spectrograph), installed at the 4.2-m WHT. Twelve out of 16 spectra yield robust (>5σ) Hα detections. We compare star formation rates (SFRs) from Hα luminosities to those derived from DEEP2 rest-frame UV measurements. This study is part of a larger program to obtain accurate Hα luminosities of about 50 star-forming galaxies at z ~ 1 in the Extended Groth Strip. Our scientific goals are the measurement of SFRs from Hα, and the comparison and calibration of Hα and other SFR tracers at z ~ 1. The study will be complemented with galaxy stellar masses, reddening estimates, galaxy morphologies and metallicities.

We present the first high resolution optical spectrum of the black hole candidate BG Geminorum, as well as UV spectroscopy from the Hubble Space Telescope, and X-ray data from INTEGRAL. The UV spectra suggest the presence of material in BG Gem with velocities possibly as high as ∼1000 km s−1, suggesting an origin at a distance of ∼0.7 R⊙ from a 3.5 M⊙ object; if real, this would be strong evidence that the primary in BG Gem is indeed a black hole. In contrast, the upper limit provided by the INTEGRAL data gives a maximum X-ray luminosity of only ∼0.1 of the Eddington luminosity.

We develop a family of transfer orbits suitable for the peculiarity of NEAs orbits. They involve one or more carefully planned deep-space maneuvers and one or more close encounters with the Earth. Basically, it is a gravity assist technique, but only Earth is used as the driving planet. In this manner, the orbit of the spacecraft stays near the Earth, as the orbits of NEAs. The idea is to obtain a large relative velocity in respect to the Earth, using these impulsive maneuvers. Next, successive rotations of this relative velocity vector due to resonant encounters with the Earth will, finally, shape the orbit of the spacecraft, in order to match the inclination and the orientation of apsidal line of the asteroid's orbit.

With a velocity budget less than 9 km/s most of NEAs orbits are reachable, even highly inclined ones, or orbits with relatively large nodal distances. An example is given: a rendezvous mission to asteroid (1036) Ganymed.

The interaction between molecular outflow from a protostar and ambient molecular cloud would play an important role in dissipating circumstellar envelope, changing chemical composition, and triggering next generation star formation. In order to investigate the interaction in submillimeter wavelength, we have made line observations toward the low mass protostar IRAS 13036-7644 (Class 0/I) in the Cha II dark cloud. Although millimeter observations found CO outflow and evidence of mass infall toward the protostar (e.g. Lehtinen 1997), no submillimeter observation has been reported so far.

New HI synthesis observations have been made for the five spiral galaxies NGC 4307, NGC 4356, NGC 4411a/b and NGC 4492, located in the Virgo Cluster Region, with the Very Large Array in its CS configuration. All these objects, but NGC 4411a, belong to a sample of spirals identified in previous single-dish studies of the HI distribution within the Virgo Cluster and its outskirts. The thirteen members of that sample were selected for showing neutral gas deficiencies as strong as those of the inner galaxies of Virgo and other rich clusters, but apparently lying on the infall region.

The goal of the present observations is to progress further on the identification of the external mechanisms that may be responsible for the reduction of the interstellar gas in spiral galaxies and thus contribute to the study of the evolution of galaxies in high-density environments. In particular, the results of this work are relevant for the ongoing debate on the pre-processing of galaxies prior to entering the cluster environment.

We present near infrared photometry of select pairs and triplets of galaxies observed with the CASPIR camera attached to the 2.3m Advanced Technology Telescope at Siding Spring Observatory, Australia. The preliminary results show that galaxies in pairs or triplets present near infrared colors that are redder than normal galaxies. We also performed a morphological analysis using bi-dimensional Fourier Transform techniques, as well as classical bulge + disk fits. Compared to isolated galaxies, the light distribution of galaxies in pairs and triplets often needs a larger number of Fourier coefficients to be well represented. Also, light profiles usually show deviations from the exponential disk (disk distortions, strong bars, etc.). In the future we intend to define some method to quantify the strength of the interactions by using the Fourier coefficients and/or the magnitude of the deviations from the classical Sersic + exponential laws.

AIMS: We analyse the photometric properties of the early-type Fornax cluster dwarf galaxy population (MV> − 17 mag), based on a wide field imaging study of the central cluster area in V and I bandpasses. We used the instrument/telescope combination IMACS/Magellan at Las Campanas Observatory, providing much larger light collecting area and better image resolution than previous wide field imaging surveys.

METHODS: We create a fiducial sample of Fornax cluster dwarf ellipticals (dEs) in the following three steps: (1) To verify cluster membership, we measured I-band surface brightness fluctuations (SBF) distances to candidate dEs known from previous surveys; (2) We re-assessed morphological classifications for those candidate dEs that are too faint for SBF detection; and (3) We searched for new candidate dEs in the size-luminosity regime close to the resolution limit of previous surveys.

RESULTS: (1) We confirm cluster membership for 28 candidate dEs in the range −16.6 < MV < −10.1 mag by means of SBF measurement. We find no SBF background galaxy. (2) Of 51 further candidate dEs in the range −13.2 < MV < −8.6 mag, 2/3 are confirmed as probable cluster members by morphological re-assessment, while 1/3 are re-classified as probable background objects. (3) We find 12 new dE candidates in the range −12.3 < MV < −8.8 mag, two of which are directly confirmed via SBF measurement. The resulting fiducial dE sample follows a well-defined surface brightness – magnitude relation, showing that Fornax dEs are about 40% larger than Local Group dEs. The sample also defines a colour-magnitude relation that appears slightly shallower than that of Local Group dEs. The early-type dwarf galaxy luminosity function in Fornax has a very flat faint end slope α ≃ −1.1 ± 0.1. We discuss these findings in the context of structure formation theories.

CONCLUSIONS: The SBF method is a very powerful tool to help constrain the faint end of the galaxy luminosity function in nearby galaxy clusters. For the Fornax cluster, morphological cluster memberships – if performed at sufficient resolution – are very reliable.

This contribution is based on Mieske et al. (2006).

Assuming that most stars form in clusters (Lada & Lada 2003), one might initially expect to find most massive stars in stellar clusters and to detect most of the UV emission in young compact stellar clusters. However, Meurer et al. (1995) showed that in starburst galaxies only 20% of the UV emission at 2200Å is detected in clusters while 80% is diffuse emission from sources in the inter-cluster medium. This phenomenon is also observed for normal galaxies (Hoopes et al. 2001).

The Rossby number Ro is an important quantity related to the well-known magnetic activity-rotation correlation for main sequence, solar-type stars. For such stars, Ro can be obtained by a semi-empirical relationship between the convective turnover time τc and the B-V colour index, but an equivalent activity-rotation correlation seems not to exist for pre-main sequence stars. In this work we report theoretical estimates of τc for low-mass, rotating pre-main sequence stars under either the Full Spectrum of Turbulence (FST) or the classical Mixing Length Theory (MLT) convection models. The results for the MLT models show that the lower the convection efficiency the higher τc, while the FST models give τc lower than those for the MLT. The presence of a parametric magnetic field lowers the convection efficiency, resulting in smaller τc values.

We present a new class of spherical galactic models with mild central cusps whose distribution function (DF) and intrinsic velocity dispersion (IV) can be represented analytically in a unified way in terms of hypergeometric functions for a large number of parameters. This allows an easy comparison of these quantities for models having varying degrees of central cuspiness or outer density falloff. In particular, we study the models for the innermost regions of galaxies harbouring mild cuspy centers with or without supermassive black holes (SBH). Important properties infered from the observed behaviour of the velocity dispersions can be reproduced.

Tests are carried out on retrieving Doppler maps from distorted stars in close binaries to estimate how Doppler imaging may be aliased by ellipticity. Maps obtained for the distorted shape are compared with the results of the simple spherical approximation, using real data of the RS CVn-type close binary star ζ Andromedae.

We discuss relativistic aspects of Earth's roration

In this paper we summarize the history and current state of astronomy in Vietnam. Future plans for the development of astronomy education and research in Vietnam are summarized and some avenues suggested. These include the construction of a planetarium in Hanoi, and the development of a curriculum for an undergraduate major and a Master's degree in astrophysics at some Universities, as well as the development and operation of an observatory in Hanoi.

We introduce a new, publicly available Monte Carlo radiative transfer code, Stokes, which has been developed to model polarization induced by scattering of free electrons and dust grains. It can be used in a wide range of astrophysical applications. Here, we apply it to model the polarization produced by the equatorial obscuring and scattering tori assumed to exist in active galactic nuclei (AGNs). We present optical/UV modeling of dusty tori with a curved inner shape and for two different dust types. The polarization spectra enable us to clearly distinguish between the two dust compositions. The Stokes code and its documentation can be freely downloaded from http://www.stokes-program.info/.

The supernova which appeared in AD 1006 is unique in history for its brilliance, duration of visibility, and the interest it aroused. Almost thirty separate records of the star are preserved from various parts of the world. This paper briefly summarizes historical records of SN 1006 and discusses the prospects of uncovering further historical records of supernovae.

We present and discuss the Hα (λ = 6563Å) observations of the contact (W UMa type) binaries AE Phoenicis and YY Eridani, obtained in 1989, 1990 and 1995 with the CAT/CES telescope of the Southern European Observatory (ESO). In particular, we compare the intrinsic equivalent widths of both components with the NextGen theoretical models and the saturation limit. We find that the average Hα equivalent widths are close to the saturation border and that the primary components have excess Hα-emission, indicating enhanced chromospheric activity. This is compatible with both theoretical and observational suggestions that the primary is the more magnetically active component and is filled with (mostly unresolvable) dark spots and associated chromospheric plages.

Selected results of 1994-2004 optical photometric and high-resolution spectral observations including those obtained in the frame of a coordinated CIS countries campaign “Optical Monitoring of Unique Astrophysical Objects” and their comparison with ASM/RXTE X-ray data are briefly reviewed.