The standard AIC (Achromatic Interfero Coronagraph) has a “coudé” geometry (the output beam leaves at right angle from the input beam). Thus, some extra optical parts are required to fit such a device within the optical train between a telescope and its IR camera. To avoid this drawback, we present two mono-axial variants of the AIC.

I present a brief summary of the parallel session on exoplanets and star formation, and how their study drives the science requirements for extremely large ground-based telescopes. I also offer a few thoughts on the development of these highly ambitious and highly expensive new astronomical facilities, as viewed from the perspective of someone also involved in the James Webb Space Telescope.

We have recently deployed a four-quadrant phase-mask coronagraph behind an unobscured, circular, off-axis section of the Palomar 200-inch telescope. To obtain very good wavefront correction across the 1.5 m subaperture, our relay optics reimage the sub-aperture onto the adaptive optics system's deformable mirror. This approach combines the advantages of low diffraction from obscuring elements, due to the off-axis aperture, with high wavefront correction, due to the magnification of the pupil, and high stellar rejection, due to the phase mask coronagraph. Our initial on-sky results include Strehl ratios exceeding 90%, peak stellar rejections of >100:1, and an improvement in contrast of 235:1 on a binary of separation $2 \lambda /D$.

Optical studies of ultraluminous X-ray sources (ULX) in nearby galaxies have turned out to be instrumental in discriminating between various models including the much advertised intermediate mass black hole hypothesis and various beaming scenarios. Here we report on ESO VLT and SUBARU observations of ULX that have revealed the parent stellar clusters with ages of some 60 million years in two cases. Thus we are able to derive upper limits of about 8 M$_{\odot}$ for the mass donors in these systems. The optical counterparts are dominated by X-ray heated accretion disks, and the discovery of the He II $\gamma$4686 emission line now allows to derive dynamical masses in these systems. Apparent radial velocity variations of 300 km/s have been detected in NGC 1313 X-2 which, if confirmed by further observations, would exclude the presence of IMBH in these systems.

We study properties of globular cluster candidates (GCCs) and the diffuse stellar populations in nearby low surface brightness dwarf galaxies, using HST WFPC2 photometry in the V and I bands. Our sample consists of 18 dwarf spheroidal (dSph), 36 dwarf irregular (dIrr), and 3 transition-type galaxies, with projected linear diameters less than 3.5 kpc and mean blue surface brightness $>23$ mag/arcsec$^2$ situated at the distance 2–6 Mpc in the field and in nearby groups. Our sample dwarf spheroidal galaxies were not detected in HI and are located at the distances of up to $\sim$1 Mpc away from a nearby bright galaxy. Transition-type galaxies, which are distributed like dSph galaxies, form a very rare class of galaxies. dIrr galaxies show a weaker concentration to the nearest massive neighbors than dSph and transition-type galaxies. At a given surface brightness and luminosity, they exhibit lower mean metallicities than dSphs. In contrast to dIrr galaxies, the majority of dSph galaxies at a similar mean surface brightness contains GCCs. The percentage of GCCs located near the centers of dSph galaxies is much higher than that for dIrr galaxies. The composite population of GCCs in dSphs is spatially more concentrated than in dIrr galaxies. The color distributions of GCCs in dSph and dIrr galaxies show major differences. While the latter shows obvious bimodality with the peaks near $(V-I)_0 \sim 0.5$ and $\sim$1.0 mag, the GCC color distribution in dSph galaxies shows only one peak with a mean color $(V-I)_0 \sim 1.0$ mag. There is a tendency of increasing half-light radii with increasing projected galactocentric distances for a large number of GCCs in dSph galaxies, which is also observed in the Galactic globular cluster system. We embarked on a spectroscopic survey of GCCs in low-mass galaxies to obtain their chemical compositions and relative ages.

Globular cluster stars exhibit abundance anomalies which are not shared by their field counterparts. Two global scenarii have been proposed in the past to explain these differences: The primordial enrichment scenario and the evolutionary (or intrinsic) one. Recent observations well below the bump luminosity in globular clusters have raised the weight of the primordial solution. However the stellar sources responsible for these abundance variations have not yet been indubitably identified. In this review we discuss the possible stellar culprits as well as their pros and cons.

We present the results of ROSAT and XMM-Newton observations of the recurrent ultraluminous X-ray source (ULX) NGC 253 ULX1. This transient is one of the few ULXs that was detected during several outbursts. The luminosity reached 1.4$\,{\times}\,10^{39}$ \hbox{erg s$^{-1}$ and $0.5\,{\times}\,10^{39}$ erg s$^{-1}$ in the detections by ROSAT and XMM-Newton, respectively, indicating a black hole X-ray binary (BHXRB) with a mass of the compact object of $>$11 M$_{\odot}$. In the ROSAT detection NGC 253 ULX1 showed significant variability, whereas the luminosity was constant in the detection from XMM-Newton. The XMM-Newton EPIC spectra are well-fit by a bremsstrahlung model (kT$=2.24\,$keV, $N_H=1.74\times10^{20} \mbox{cm}^{-2}$), which can be used to describe a comptonized plasma. No counterpart was detected in the optical I, R, B, NUV and FUV bands to limits of 22.9, 24.2, 24.3, 22 and 23 mag, respectively, pointing at a XRB with a low mass companion.

We illustrate the need for planning surveys and coordinated observations, using representative science cases developed for ELTs by the GSMT Science Working Group. We conclude that enabling surveys and coordinated observations is critical to ELTs and that ground-based optical and radio and space-based facilities are needed. A world-wide systems approach is needed to support ELT campaigns. We discuss early planning for ELT operations, based on discussions in progress within the TMT partnership. We conclude that developing an architecture to accommodate end-to-end observation and data management will be essential to achieving near-term and legacy goals.

We present preliminary results of a few observing programs conducted with the FLAMES fiber facility at VLT2 ESO telescope. These programs show the large potentiality of FLAMES for investigations of globular clusters. The programs described here concern the derivation of precise reddening and metallicity for globular clusters, and the derivation of abundances for stars on the main sequence of ω Cen. Reddenings with errors of $\Delta E(B-V)=0.005$ mag and metallicities with errors of ±0.02 dex (in a scale defined by local subdwarfs) can be obtained in very short observing time. Our results for ω Cen show that the blue main sequence is more metal-rich than the red-main sequence: this requires a large He-content for the blue main sequence.

We present configurations of shaped pupil coronagraphs optimized for a realistic telescope to directly detect extrasolar giant planets in the mid-IR wavelengths. This study is linked to the development of the coronagraphic instrument aboard SPICA (SPace Infrared telescope for Cosmology and Astrophysics). We made a systematic assessment of the performance of the “checkerboard” and “concentric ring” masks, introducing a large central obstruction (C.O.) due to a secondary mirror and its related support spiders. With a small secondary mirror, we also propose a modification to the original symmetrical checkerboard apodization, which enables us to achieve a $10^{-7}$ contrast level at $4.0\ \lambda/D$. The transmission through the optimal binary masks exhibits abrupt increases and plateaus as the inner working angle (IWA) is increased. We attribute these properties of binary apodization function to the existence of threshold IWAs that allow large openings in the pupil.

We present the internal velocity dispersions and spectral line indices for six Virgo ultra-compact dwarf (UCD) galaxies obtained from spectroscopy with the Keck II 10-m telescope. We use these results: 1) to compare the Virgo UCDS with the Fornax UCD population; 2) to compare UCDs with globular clusters (GCs) to determine if UCDs and the most luminous GCs are the same or distinct systems; 3) to further test the nucleated dwarf elliptical (dE,N) stripping hypothesis for UCD formation.

We examine the properties of ten compact objects in the vicinity of M87 using HST imaging and Keck spectroscopy. We find three objects to be larger and brighter than typical globular clusters; they resemble the nuclei of nucleated dEs in Virgo, having similar mass-to-light ratios, luminosities and colors. Their properties are consistent with models of tidally stripping of nucleated dEs. One object could be an old “stellar supercluster”, formed through the amalgamation of multiple young massive clusters. Two other objects appear to be massive versions of otherwise “normal” globular clusters.

We detail a model we have created to describe the optical emission from a ULX in terms of an irradiated companion star and disk. We apply this model to optical observations of ULX X-7 in NGC 4559. We revise the parameters of the companion star in this system to be older, less massive and of a later spectral type than previously reported. We find the black hole to be of a few hundred solar masses at most.

This paper presents the final discussion of the meeting, following introductory remarks by A. Ardeberg, B. Ellerbroek and C. Cunningham.

Lithium abundance in Turnoff stars of Globular Clusters (GC) provide precious information about primordial nucleosynthesis and Globular Cluster formation. Out of the three GC so far observed in some detail, the metal poor NGC6397 shows a constant Li abundance, at the same level of the Spite' plateau; while the more metal rich NGC6752 and 47 Tuc show a beautiful Li-Na anticorrelation (the first of this kind observed in PoP II stars), suggesting the presence of gas processed by a previous generation of stars. These observations are quite puzzling: while they are qualitatively compatible with the scenario of contamination from intermediate mass AGB stars, no progenitor can quantitatively reproduce the observations. Beryllium has also been detected in NGC6397 Turnoff stars, indicating that the gas which formed the stars was exposed for about 200 Myr to the Galactic Cosmic Rays. The emerging picture seems to require that in the early Galaxy both local (SNae, AGB stars) and global (Galactic Cosmic Rays) enrichment processes were acting simultaneously in the star formation phase of the halo.

We present new laboratory measurements of the intrinsic rejection performances in infrared (1.9 $\mu\,$m to 2.5 $\mu\,$m) for a prototype of Achromatic Interfero Coronagraph (AIC). We first recall basics about the AIC, then describe the prototype under consideration. We give detailed explanations about the experimental setup and the procedures followed to measure the rejection rate. We end up with a discussion of the results obtained.

The high contrast (typically $10^{10}$) and small angular separation between a planet and its parent star are the main challenges that need to be overcome to detect and characterize Earth-like planets around the nearest stars. Therefore, exoplanet imaging requires the use of a coronagraph, that ideally efficiently cancels the light from the star and has minimal influence on the planet image. The Phase Induced Amplitude Apodization Coronagraph relies on pupil apodization by geometrical remapping of the flux in the pupil plane. This method combines the advantages of classical pupil apodization with high throughput ($\approx$100%) and high angular resolution (${\approx}\lambda/D$), and has some unique advantages over most coronagraphs, such as low chromaticity, low sensitivity to stellar angular size and to small pointing errors. As a result, planet detection time is about 50–100 times shorter in comparison with classical coronagraphic techniques (Martinache et al. 2005).

Both the advantages of the PIAAC and the main factors affecting the performance of the coronograph will be examined in our laboratory experiment in which high quality PIAA optics wilkl be combined with wavefront control to demonstrate achromatic high contrast imaging ($10^6$ or more) at small angular separation (less than $2\lambda/D$). We present here a description and current status of this experiment together with a short analyses of the main factors affecting the performance of the coronograph.

We present optical observations of an ultraluminous X-ray source (ULX) in Holmberg IX, a dwarf galaxy near M81. The ULX has an average X-ray luminosity of some $10^{40}$ erg/s. It is located in a huge (400pc$\,{\times}\,$300pc) ionized nebula being much larger than normal supernova remnants. From the observed emission lines (widths and ratios) we find that the structure is due to collisional excitation by shocks, rather than by photoionization.

We identify the optical counterpart to be a 22.8 mag blue star ($M_V=-5.0$) belonging to a small stellar cluster. From isochrone fitting of our multi-colour photometry we determine a cluster age of some 60 Myr. We also discovered strong stellar HeII$\lambda$4686 emission (equivalent width of $\mbox{10 \AA}$) which proves the identification with the X-ray source, and which suggests the presence of an X-ray heated accretion disc around the putative black hole.

The technical developments required to build the future Extremely Large Telescopes will be very demanding. Some of these developments, for instance in the field of Adaptive Optics, will rely on experimental work to test new techniques and concepts. The 4.2-m William Herschel Telescope located at a representative high-quality observing site, and with its stable Nasmyth optical bench for general access and its common-user Rayleigh laser beacon, is well placed to play a role as a testbed facility for such activities.

Using the 2dF multi-fibre instrument on the Anglo-Australian Telescope, moderate resolution spectra have been obtained for a large sample of stars on the main sequence and at the turnoff in the unusual globular cluster ω Cen. We investigate the behaviour of CH, CN and SrII line strength indices as a function of overall abundance for the main sequence sample. A number of stars do not follow the relations defined by the majority. These anomalous objects can be categorized into (at least) three types. (1) Carbon enhanced stars, which represent about 5% of the sample, and which are found at all metallicities. Spectrum synthesis calculations show that the atmospheres of these stars are typically enhanced in carbon by factors of between 3 and 10. (2) Nitrogen enhanced stars, revealed for [Fe/H] [ges ]–1.3 by strong CN indices, which make up ∼40% of the cluster main sequence population above this metallicity. The stars are enhanced in nitrogen by factors of up to 100. Our data, however, provide no constraints on their relative numbers at lower [Fe/H]. (3) Stars with enhancements of the s-process element Sr by factors of 30 to 60. The possible origins for these abundance anomalies are discussed.