We show observations obtained with the integral field spectrometer OASIS for the centers of a sample of barred galaxies. The high spatial resolution of the instrument allows to distinguish spatially some structures within these regions as defined by stellar populations of different ages and metallicities. From these data we deduce important clues about the star formation history. But we advise that, in order to obtain adequately the evolutionary sequence, a combination of chemical and synthesis models might be necessary.

We present high resolution observations of SiO masers in the late-type star R Cas as part of a multi-line study of SiO circumstellar masers in oxygen-rich AGB stars. We used the NRAO Very Long Baseline Array (VLBA) to map the 43 GHz maser emission of 28SiO. We study the relative spatial distribution of the different maser lines and discuss the relevance of line overlaps in the SiO pumping theory.

We have re-analyzed observations of the water maser emission in IRAS 17347-3139 carried out previously and compared them with new higher angular resolution and more sensitive radio-continuum observations to explain the shift between the position of the peak of the radio-continuum with respect to the center of the ring-like distribution. From our analysis, we found that the water maser emission is not distributed in a closed ring-like structure, but in what appears to be a segment of an ellipse centered in the position of the peak of the radio-continuum. These results can explain the shift between the radio-continuum and the water maser emission. We also present interferometric observations of the OH maser emission towards IRAS 17347-3139 from which we have found that the OH maser emission detected previously is not associated with this source. Furthermore, since our observations are more sensitive, we have detected for the first time weak OH maser emission associated with IRAS 17347-3139.

The luminosity profile of M 83 bulge can be traced by a de Vaucouleurs' law between ≈ 200 pc and ≈ 800 pc. The inner part can be fitted by a n = −1/2 Sérsic profile. Also the IR (J − K) color shows difference between the periphery and the central part of the bulge, both properties indicating the presence of a pseudobulge. Previous Gemini-S 3-D, Paβ spectroscopy of the central ≈ 5″×13″ revealed spider like diagrams indicating disk like motion around three extended masses identified respectively with the optical nucleus (ON), with the center of the bulge isophotes, similar to the CO kinematical center (KC), and with a condensation hidden at optical wavelengths (HN), coincident with the largest lobe in 10 μm emission, most probably a cannibalized satellite. Numerical simulations show that they suffer strong evaporation and they would merge engulfing also the star forming arc in few hundred Myr, increasing the mass at the kinematical center by a factor o five or more. Upper mass limit of putative Black Holes associated to ON, KC and HN are a few ten thousand to a million solar masses. GMOS+Gemini imaging and spectroscopy of a chain of radio sources has yield no optical high redshift counterparts. This radio sources are aligned with ON, neither associated to SN nor to HII regions and might point to an older similar phenomenon, which left behind a kick-off spur.

The Gaia Science Operations Centre (SOC), based at ESAC near Madrid, is building up to play an important role in Gaia operations and data processing.

We report on XMM-Newton and Chandra observations of the globular cluster NGC 2808. We detect one quiescent low mass X-ray binary of the 3±1 expected, if these systems are formed through encounters, and we show evidence for the presence of 20±10 bright cataclysmic variables in the core with a luminosity above 4×1031 erg s−1. We also review the specific nature of cataclysmic variables in globular clusters with reference to recent VLT/FORS1 observations of a cataclysmic variable in M 22.

We present a brief update on the ACS Virgo and Fornax Cluster Surveys — Hubble Space Telescope programs to obtain ACS imaging for 143 early-type galaxies in the two galaxy clusters nearest to the Milky Way. We summarize a selection of science highlights from the surveys as including new results on the central structure of early-type galaxies, the apparent continuity of photometric and structural parameters between dwarf and giant galaxies, and the properties of globular clusters, diffuse star clusters and ultra-compact dwarf galaxies.

OH (1720 MHz) masers serve as indicators of SNR – molecular cloud interaction sites. These masers are collisionally excited in warm (50–100 K) shocked gas with densities of order 105cm−3 when the OH column density is in the range 1016−1017cm−2. Here I present excitation calculations which show that when the OH column density exceeds 1017cm−2 at similar densities and temperatures, the inversion of the 1720 MHz line switches off and instead the 6049 MHz transition in the first excited rotational state of OH becomes inverted. This line may serve as a complementary signal of warm, shocked gas when the OH column density is large.

We present results on the stellar populations of a sample of 18 late-type spirals, based on data acquired with the integral-field spectrograph SAURON at the WHT. We present the two-dimensional line-strength maps, the central line indices, and estimate the star formation time-scale. In an exponentially declining SFR scenario, we find a trend between the time-scale τ and the central velocity dispersion: more massive galaxies show shorter burst durations. A detailed study on these data is published by Ganda et al. (2007).

We are preparing a reflecting telescope for Nano-JASMINE, a very small satellite for global space astrometry of milli-arcsecond accuracy. The telescope has a 5-cm diameter primary mirror and a beam-combiner in front of it. It occupies only about 12x12x17cm and is entirely made out of aluminum alloy. The telescope and its surrounding structures are carefully designed for thermal stability of the optics, especially to control changes in the relative angle of the beam-combiner.

Explorations of the globular cluster populations in many nearby galaxies are revealing increasing connections to other dense stellar systems such as UCDs, DGTOs, and nuclear star clusters in dwarf galaxies. The nearest giant elliptical, NGC 5128, is now giving us a much-improved delineation of the GC Fundamental Plane of structural parameters, and indicates as well that the known correlation between GC scale size and metallicity is likely to be at least partly a projection effect coupled with the different spatial distributions of the metal-poor and metal-rich clusters. New photometry of the huge cluster populations around the giant Brightest Cluster Ellipticals, which allows us to study samples of many thousands of GCs at once, are now beginning to turn up surprising examples of “sequences” of high-mass GCs leading up to the UCD regime. Lastly, new modelling of cluster formation through a specially tuned semi-analytic galaxy formation code strongly suggests that the mass-metallicity relation now known to affect the blue GC sequence can arise fairly naturally out of such models, if significant numbers of the massive GCs actually represent the remnant nuclei of stripped dwarf satellites.

We present a study of the internal kinematics and stellar populations of early-type galaxies in the Fornax cluster. 10 galaxies in a luminosity range of −21.8≤MB≤−17.4 were observed with the integral field units (IFU) of Gemini South GMOS and VLT-VIMOS. Velocity maps and age-metallicity diagrams are presented for NGC 1404 and NGC 1419.

We report high-resolution observations of H2O, 61,6−52,3 and 28SiO v=2, J=1-0 maser emissions obtained with the Very Long Baseline Array in the bipolar pre-planetary nebulae OH 231.8+4.2 (see Desmurs et al., 2007). A phase referencing technique was used to recover the absolute position of both emissions. We detected two groups of water vapour emission oriented nearly north-south. SiO masers are tentatively found to be placed between the two H2O maser emitting regions.

Many small ground-based telescopes (with diameter less than 2m) allow us to perform programs of observations well adapted to astrometric measurements. The improvement of limiting magnitudes thanks to the use of CCD detector and their availability make them very useful for follow-up programs or observations on alert. This communication gives several examples of research carried out by members of the IAU working group “Astrometry by small ground-based telescopes”. We also propose setting up of a network of observers for the Gaia follow-up observations.

Optical astrometry of quasars and active galaxies can provide key information on the spatial distribution and variability of emission in compact nuclei. The Space Interferometry Mission (SIM PlanetQuest) will have the sensitivity to measure a significant number of quasar positions at the microarcsecond level. SIM will be very sensitive to astrometric shifts for objects as faint as V=19. A variety of AGN phenomena are expected to be visible to SIM on these scales, including time and spectral dependence in position offsets between accretion disk and jet emission. These represent unique data on the spatial distribution and time dependence of quasar emission. It will also probe the use of quasar nuclei as fundamental astrometric references. Comparisons between the time-dependent optical photocenter position and VLBI radio images will provide further insight into the jet emission mechanism. Observations will be tailored to each specific target and science question. SIM will be able to distinguish spatially between jet and accretion disk emission; and it can observe the cores of galaxies potentially harboring binary supermassive black holes resulting from mergers.

We present H2O masers associated with the massive-star forming region G192 observed with the Japan VLBI network since the year 2005, The spatio-kinematical structure of the maser feature clusters has well persisted since previous observations, in which the masers are associated with two young stellar objects (YSOs) separated by ~1200 AU and expected to be associated with a highly-collimated bipolar jet and an infalling-rotating disk in the northern and southern YSOs, respectively. We estimated a jet speed of ~100 km s−1 and re-estimated a dynamical age of the whole jet to be 5.6×104 years. The spatial distribution of maser Doppler velocities found during the previous and present observations, relative proper motions of H2O maser features in the southern cluster found in the present observations, a relative bulk motion between the two maser clusters are well explained by a model of an infalling-rotating disk with a radius of ~1000 AU and a central stellar mass of ~8 M⊙.

We present the results on our investigation of the age structure in early-type galaxies, based on optical/near-infrared photometry. First results have shown that the age structure in early-type galaxies is not as uniform as previously thought. The conclusion can only be that the formation of these galaxies is not exclussively based on a single scenario, e.g. monolithic collapse, or hierarchical merging. In our galaxy survey we compare the age structure of galaxies in different galaxy environment, of different mass and with different integral light properties, using the globular cluster systems as stellar probes. Depending on the size of the globular cluster sample we derive a cumulative age distribution and compare it to simulated systems with a known age structure. This allows us to detect globular cluster sub-populations with an age difference of several Gyr. So far we have found two galaxies, members of small groups of galaxies, which contain a significant population of intermediate age globular clusters in the inner region of the galaxy.

This paper reviews some of the observational properties of globular cluster systems, with a particular focus on those that constrain and inform models of the formation and dynamical evolution of globular cluster systems. I first discuss the observational determination of the globular cluster luminosity and mass function. I show results from new very deep HST data on the M87 globular cluster system, and discuss how these constrain models of evaporation and the dynamical evolution of globular clusters. The second subject of this review is the question of how to account for the observed constancy of the globular cluster mass function with distance from the center of the host galaxy. The problem is that a radial trend is expected for isotropic cluster orbits, and while the orbits are observed to be roughly isotropic, no radial trend in the globular cluster system is observed. I review three extant proposals to account for this, and discuss observations and calculations that might determine which of these is most correct. The final subject is the origin of the very weak mass-radius relation observed for globular clusters. I discuss how this strongly constrains how globular clusters form and evolve. I also note that the only viable current proposal to account for the observed weak mass-radius relation naturally effects the globular cluster mass function, and that these two problems may be closely related.

Stellar kinematics show no evidence of hidden mass concentrations at the centre of M83. We show the clearest evidence yet of an age gradient along the starburst arc and interpret the arc to have formed from orbital motion away from a starforming region in the dust lane.

GAME (Gamma Astrometric Measurement Experiment) is a concept for an experiment whose goal is to measure from space the γ parameter of the Parameterized Post-Newtonian formalism, by means of a satellite orbiting at 1 AU from the Sun and looking as close as possible to its limb. This technique resembles the one used during the solar eclipse of 1919, when Dyson, Eddington and collaborators measured for the first time the gravitational bending of light. Simple estimations suggest that, possibly within the budget of a small mission, one could reach the 10−6 level of accuracy with ~106 observations of relatively bright stars at about 2° apart from the Sun. Further simulations show that this result could be reached with only 20 days of measurements on stars of V ≤ 17 uniformly distributed. A quick look at real star densities suggests that this result could be greatly improved by observing particularly crowded regions near the galactic center.