We perform the two-dimensional radiation-hydrodynamic simulations to study the radiation pressure-dominated accretion flows around a black hole (BH). Our simulations show that the highly supercritical accretion flow (mass accretion rate is much larger than the critical value) is composed of the disk region and the outflow region above the disk.

The radiation force supports the thick disk and drives the outflow. The photon trapping plays an important role within the disk, reducing the disk luminosity. On the other hand, in the case that mass accretion rate moderately exceeds the critical value, we find that the disk is unstable and exhibits the limit-cycle oscillations. The disk oscillations in our simulations nicely fit to the variation amplitude and duration of quasi-periodic luminosity variations observed in the GRS 1915+105 microquasar.

Two Moroccan sites have been selected to be characterized for the ELT telescopes. Those sites are in the Atlas, between Oukaïmeden (where the national observatory is situated) and the Canary Islands. For this preliminary study, we have used the Nimbus-7 TOMS aerosol index to derive the astronomical extinction. This work builds on the findings of an earlier study which established the link between these two parameters over the Canary Islands.

The NSF Science and Technology Center for Adaptive Optics (CfAO) is supporting a major scientific legacy project called the CfAO Treasury Survey (CATS). CATS is obtaining near-infrared AO data in deep HST survey fields, such as GEMS, GOODS-N, & EGS. Besides summarizing the main objectives of CATS, we highlight some recent imaging work on the study of distant field galaxies, AGNs, and a redshift z = 1.32 supernova. CATS plans the first data release to the community in early 2007 (check http://www.astro.ucla.edu/~irlab/cats/index.shtml for more details on CATS and latest updates).

Young massive star-forming regions are known to produce hot molecular gas cores (HMCs) with a rich chemistry. While this chemistry is interesting in itself, it also allows to investigate important physical parameters. I will present recent results obtained with high-angular-resolution interferometers disentangling the small-scale structure and complexity of various molecular gas components. Early attempts to develop a chemical evolutionary sequence are discussed. Furthermore, I will outline the difficulty to isolate the right molecular lines capable to unambiguously trace potential massive accretion disks.

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

We study solar irradiance variability. The current generation of models show that the irradiance since then has increased by between 0.9 and 1.5 W m−2.

The Committee on Space Research (COSPAR) Capacity-Building Programme introduces astronomers in the developing world to the rich resource of space research online archives. The programme consists of a series of regional workshops which each bring together about 30 developing world astronomers with around 8 teaching faculty for lectures and hands-on projects. Five workshops have been held so far with another two planned for next year and a budget which enables on average one workshop each year. Proposals for future workshops are encouraged.

This summary covers the first two days of the Symposium, in which the oral papers were primarily observational in nature. It also mentions several of the many observational posters associated with those discussions.

We present HI observations of the elliptical galaxy NGC 2974, obtained with the VLA. These observations reveal that the previously detected HI disc in this galaxy (Kim et al. 1988) is in fact a ring. Combining the flat rotation curve with the central kinematics of the ionised gas, obtained with the integral-field spectrograph SAURON, allows us to determine the mass-to-light ratio M/L as a function of radius, ranging from 100 pc in the centre to 10 kpc at the edges of the HI ring. A dark halo is required to explain the observed rotation: at the outer radii ~70% of the total mass is dark†.

Dome C, Antarctica is a prime site for astronomical observations in terms of climate, wind speeds, turbulence, and infrared and terahertz sky backgrounds (for example, see Aristidi et al. 2005; Storey et al. 2005). However, at present little is known about the optical sky brightness and atmospheric extinction. Using a variety of modelling techniques, together with data from the South Pole, the brightness of the night sky at Dome C is estimated in Kenyon & Storey (2006) including the contributions from scattered sunlight, moonlight,aurorae, airglow, zodiacal light, integrated starlight, diffuse Galactic light and artificial sources. The results are compared to Mauna Kea, Hawaii. We summarise the main conclusions.

We have obtained the first accurate determination of the albedo of (99942) Apophis, by means of polarimetric observations carried out at the VLT. The observations allowed us to obtain the slope of the polarization–phase curve of this object, from which an albedo estimate of 0.33 ± 0.04 could be obtained. From our observations we also obtained a new estimate of the absolute magnitude: H = 19.7 ± 0.2 (assuming G=0.25, which applies to S- and Q-type asteroids). Based on these results, we derive for the size of Apophis a value of 270 ± 30 meters. The accuracy of this size estimate is mostly related to uncertainties in H, whereas the obtained albedo value should be considered more robust. Our observations convincingly show that polarimetry is an effective and efficient tool to obtain accurate albedos and sizes for small and faint potentially hazardous asteroids.

We have redetermined the absolute dimensions of the mid B-type eclipsing binary U Oph from new light and radial-velocity curves, accounting for both the apsidal motion and the light-time orbit around the third star. The stars in U Oph have masses of 5.27 and 4.74 M⊙(±1.5%) and are located in the middle of the main-sequence band for an an age of ∼50 Myr. U Oph and three other systems (V760 Sco, MU, Cas and DI Her) all have components within 10% of 5M⊙ and ages below 100 Myr; we find significant heavy-element abundance differences between these young nearby stars.

We give estimates of the global mass-loss rate from bulge stars and show that this supply of gas is not negligible for the mass budget of the central kiloparsec in comparison with mass inflow rate predicted by N-body simulations of barred galaxies and mergers.

We dicuss new Galactic ISM results and progress towards low-frequency spectroscopy

Disks of galaxies in clusters are deeply affected by interactions. We investigate the pattern speed of galaxies in cluster in order to detect a possible dependence with cluster environmental parameters, such as galaxies density. If the perturbation of cluster galaxies is mainly produced by the interaction with the cluster ambient, the pattern speed might well depend on the history of the galaxy orbit within the cluster. Tremaine & Weinberg (1984) method is applied to 2-D Hα velocity fields, reconstructed from the isovelocity contours published by Amram et al. (1992), and 2-MASS K–band images (Skrutskie 2001) to obtain spirals pattern angular speed. The use of K–band images and Hα velocity maps is justified by the fact that the perturbations imprinted in Hα velocity maps are produced by the old stellar population which emits most of its energy in the near-IR. We analyzed Pegasus I cluster galaxies NGC 7593, NGC 7631 and NGC 7643 (this one shown in Figure 1). Preliminary results indicates that NGC 7593 presents a pattern speed Ωp sin(i) = 18 ± 5km s−1 kpc−1, (inclination i = 51°) while NGC 7631 and NGC 7643 pattern speeds are Ωp sin(i) = 21 ± 4 km s−1 kpc−1 and Ωp sin(i) = 35 ± 3 km s−1 kpc−1 (inclinations i = 64° and 59° respectively). In the three successful cases the correlation coefficients in the 〈X〉 vs 〈V〉 plots are 0.94, 0.95 and 0.98 respectively. We are presently analyzing other galaxies in the cluster.

Results based on the deep imaging survey of the inner region (~300pc of the bulge within |ℓ| ~ 1.5°, |b| ~ 0.5°) of the Milky Way are reported in this communication. This survey is about 2.5 magnitude deeper than DENIS and 2MASS and is able to detect stars of the red clump at a distance of the Galactic center. Toward some directions we find extinction reaching AV = 50 mag. A catalog of the sources is in preparation.

We present VisIVO a software for the visualisation and analysis of astrophysical data which can be retrieved from the Virtual Observatory framework and for cosmological simulations. VisIVO is VO standards compliant and supports the most important astronomical data formats such as FITS, HDF5 and VOTables. Data can be retrieved directly connecting to an available VO service (i.e., VizieR WS), loaded in the local computer memory where they can be further selected, visualised and manipulated.

It is well known that rotating inviscid accretion flows with adequate injection parameters around black holes could form shock waves close to the black holes, after the flow passes through the outer sonic point and can be virtually stopped by the centrifugal force. We numerically examine such shock waves in 2D accretion flows with 10−5 to 106 Eddington critical accretion rates around a supermassive black hole with 106M⊙. As the results, the luminosities show QPO phenomena with modulations of a factor 2–3 and with quasi-periods of a few to several hours.

We present new spectroscopic observations of the system of the two blue compact dwarf (BCD) galaxies SBS 0335-052 W and SBS 0335-052 E with the 3.6m ESO telescope. The oxygen abundance in SBS 0335-052 W was determined to be 12 + log(O/H) = 7.13±0.08, confirming that this galaxy is the most metal-deficient emission-line galaxy known. We find that the oxygen abundance in SBS 0335-052 E varies from region to region in the range from 7.20 to 7.31, suggesting the presence of an abundance gradient over a spatial scale of ~1 kpc. Signatures of early carbon-type Wolf-Rayet stars are detected in cluster #3 of SBS 0335-052 E, corresponding to the emission of 20 to 130 WC4 stars, depending on the adopted luminosity of a single WC4 star in the Civ λ4658 emission line (Papaderos et al. 2006).

We investigate some implications of having two star formation episodes in globular clusters, rather than the traditional single-burst approximation. Evidence for more than one stellar generation is accumulating in observations of abundances of elements lighter than iron in globular cluster stars, and is thought to imply some self-enrichment of the globular cluster gas. In particular, we explore models based on the assumption that the self-enrichment comes from an early generation of asymptotic giant branch (AGB) stars.