The Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey aims to characterise the physical and chemical evolution of high-mass star-forming clumps. Exploiting the unique broad frequency range and on-the-fly mapping capabilities of the Australia Telescope National Facility Mopra 22 m single-dish telescope1, MALT90 has obtained 3′ × 3′ maps towards ~2 000 dense molecular clumps identified in the ATLASGAL 870 μm Galactic plane survey. The clumps were selected to host the early stages of high-mass star formation and to span the complete range in their evolutionary states (from prestellar, to protostellar, and on to $\mathrm{H\,{\scriptstyle {II}}}$ regions and photodissociation regions). Because MALT90 mapped 16 lines simultaneously with excellent spatial (38 arcsec) and spectral (0.11 km s−1) resolution, the data reveal a wealth of information about the clumps’ morphologies, chemistry, and kinematics. In this paper we outline the survey strategy, observing mode, data reduction procedure, and highlight some early science results. All MALT90 raw and processed data products are available to the community. With its unprecedented large sample of clumps, MALT90 is the largest survey of its type ever conducted and an excellent resource for identifying interesting candidates for high-resolution studies with ALMA.

PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. The atmospheric conditions at Dome C deliver a high sensitivity, high photometric precision, wide-field, high spatial resolution, and high-cadence imaging capability to the PILOT telescope. These capabilities enable a unique scientific potential for PILOT, which is addressed in this series of papers. The current paper presents a series of projects dealing with the nearby Universe that have been identified as key science drivers for the PILOT facility. Several projects are proposed that examine stellar populations in nearby galaxies and stellar clusters in order to gain insight into the formation and evolution processes of galaxies and stars. A series of projects will investigate the molecular phase of the Galaxy and explore the ecology of star formation, and investigate the formation processes of stellar and planetary systems. Three projects in the field of exoplanet science are proposed: a search for free-floating low-mass planets and dwarfs, a program of follow-up observations of gravitational microlensing events, and a study of infrared light-curves for previously discovered exoplanets. Three projects are also proposed in the field of planetary and space science: optical and near-infrared studies aimed at characterising planetary atmospheres, a study of coronal mass ejections from the Sun, and a monitoring program searching for small-scale Low Earth Orbit satellite debris items.

PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. Conditions at Dome C are known to be exceptional for astronomy. The seeing (above ∼30 m height), coherence time, and isoplanatic angle are all twice as good as at typical mid-latitude sites, while the water-vapour column, and the atmosphere and telescope thermal emission are all an order of magnitude better. These conditions enable a unique scientific capability for PILOT, which is addressed in this series of papers. The current paper presents an overview of the optical and instrumentation suite for PILOT and its expected performance, a summary of the key science goals and observational approach for the facility, a discussion of the synergies between the science goals for PILOT and other telescopes, and a discussion of the future of Antarctic astronomy. Paper II and Paper III present details of the science projects divided, respectively, between the distant Universe (i.e. studies of first light, and the assembly and evolution of structure) and the nearby Universe (i.e. studies of Local Group galaxies, the Milky Way, and the Solar System).

The cold, dry, and stable air above the summits of the Antarctic plateau provides the best ground-based observing conditions from optical to sub-millimetre wavelengths to be found on the Earth. Pathfinder for an International Large Optical Telescope (PILOT) is a proposed 2 m telescope, to be built at Dome C in Antarctica, able to exploit these conditions for conducting astronomy at optical and infrared wavelengths. While PILOT is intended as a pathfinder towards the construction of future grand-design facilities, it will also be able to undertake a range of fundamental science investigations in its own right. This paper provides the performance specifications for PILOT, including its instrumentation. It then describes the kinds of projects that it could best conduct. These range from planetary science to the search for other solar systems, from star formation within the Galaxy to the star formation history of the Universe, and from gravitational lensing caused by exo-planets to that produced by the cosmic web of dark matter. PILOT would be particularly powerful for wide-field imaging at infrared wavelengths, achieving near diffraction-limited performance with simple tip–tilt wavefront correction. PILOT would also be capable of near diffraction-limited performance in the optical wavebands, as well be able to open new wavebands for regular ground-based observation, in the mid-IR from 17 to 40 μm and in the sub-millimetre at 200 μm.

We present a new model for the formation of dense clumps and pillars around HII regions based on shocks curvature at the interface between a HII region and a molecular cloud. UV radiation leads to the formation of an ionization front and of a shock ahead. The gas is compressed between them forming a dense shell at the interface. This shell may be curved due to initial interface or density modulation caused by the turbulence of the molecular cloud. Low curvature leads to instabilities in the shell that form dense clumps while sufficiently curved shells collapse on itself to form pillars. When turbulence is high compared to the ionized-gas pressure, bubbles of cold gas have sufficient kinetic energy to penetrate into the HII region and detach themselves from the parent cloud, forming cometary globules.

Using computational simulations, we show that these new models are extremely efficient to form dense clumps and stable and growing elongated structures, pillars, in which star formation might occur (see Tremblin et al.2012a). The inclusion of turbulence in the model shows its importance in the formation of cometary globules (see Tremblin et al.2012b). Globally, the density enhancement in the simulations is of one or two orders of magnitude higher than the density enhancement of the classical “collect and collapse“ scenario. The code used for the simulation is the HERACLES code, that comprises hydrodynamics with various equation of state, radiative transfer, gravity, cooling and heating.

Our recent observations with Herschel (see Schneider et al.2012a) and SOFIA (see Schneider et al.2012b) and additional Spitzer data archives revealed many more of these structures in regions where OB stars have already formed such as the Rosette Nebula, Cygnus X, M16 and Vela, suggesting that the UV radiation from massive stars plays an important role in their formation. We present a first comparison between the simulations described above and recent observations of these regions.

Over the past few years a major effort has been put into the exploration of potential sites for the deployment of submillimetre (submm) astronomical facilities. Amongst the most important sites are Dome C and Dome A on the Antarctic Plateau, and the Chajnantor area in Chile. In this context, we report on measurements of the sky opacity at 200 μm over a period of three years at the French-Italian station, Concordia, at Dome C, Antarctica. Based on satellite data, we present a comparison of the atmospheric transmission at 200, 350 μm between the best potential/known sites for submillimetre astronomy all around the world.

The precipitable water vapour (PWV) was extracted from satellite measurements of the Infrared Atmospheric Sounding Interferometer (IASI) on the METOP-A satellite, between 2008 and 2010. We computed the atmospheric transmission at 200 μm and 350 μm using the forward atmospheric model MOLIERE (Microwave Observation LIne Estimation and REtrieval). This method allows us to compare known sites all around the world without the calibration biases of multiple in-situ instruments, and to explore the potential of new sites.

Because modern astronomy associates the quest of our origins and high-tech instruments, communicating and teaching astronomy explore both science and technology. We report here on our work in communicating astronomy to the public through Web sites (www.herschel.fr), movies on Dailymotion (www.dailymotion.com/AstrophysiqueTV) and new ITC tools that describe interactively the technological dimension of a space mission for astrophysics.

Submillimeter dust continuum emission traces high molecular column densities and, thus, dense cloud regions in which new stars are forming. Surveys of the Galactic plane in such emission have the potential of delivering an unbiased view of high-mass star formation throughout the Milky Way. The location of the APEX telescope on the Chajnantor plateau in Chile is ideally suited for mapping the inner Galaxy. ATLASGAL, The APEX Telescope Large Area Survey of the Galaxy at 870 μm, is a survey of the Galactic plane using the Large APEX Bolometer Camera (LABOCA), in the Galactic longitude and latitude ranges of  ±60 and  ±1.5°, respectively. This survey is providing an unbiased sample of cold dusty clumps in the Galaxy at submillimeter wavelength and a variety of molecular line follow-up observations have been started to characterize the physical and chemical conditions in the newly found clumps. Here, first results from this survey and its follow-up programs are described.

The Rosette molecular cloud has a characteristic morphology, where the central OB cluster NGC 2244 has blown a circular-shaped cavity into the cloud and the expanding HII-region now interacts with the cloud. We use continuum data obtained with the PACS (70 and 160 μm) and SPIRE instruments (250, 350, 500 μm) of the Herschel telescope to investigate the spatial distribution of cold and warm gas and to locate all star-forming sites in Rosette. We detected a clear negative temperature gradient and a positive density gradient (running from the HII-region/molecular cloud interface into the cloud), and an age-sequence (from more evolved to younger) with increasing distance to the cluster NGC 2244. The existence of such temperature and density gradients and the observed age-sequence imply that star formation in Rosette may indeed be influenced by the radiative impact of the central NGC 2244 cluster.

This report aims to provide a summary of the status of our Antarctic Submillimetre Telescope (AST) project up to date. It is a very new project for Antarctic astronomy. Necessary prerequisites for a future deployment of a large size telescope infrastructure have been tested in years 2007 and 2008. The knowledge of the transmission, frost formation and temperature gradient were fundamental parameters before starting a feasibility study. The telescope specifications and requirements are currently discussed with the industrial partnership.

We present model calculations of the atmospheric transmission for DOME C in Antarctica for frequencies up to 10 THz (30 μm) using the forward model MOLIERE-5. Measurements of precipitable water vapor (pwv), obtained by the SUMMIT radiometer installed at the Concordia station during 2008 and working at a wavelength of 200 μm, are translated into atmospheric transmission using MOLIERE. Quartiles of transmission, calculated from 200 μm data are extrapolated to 350 μm and compared to the CCAT (Cornell-Caltech Atacama Telescope) site in Chile. It turns out that for 25% of the time at DOME C (CCAT), the transmission is around 20% (5%) at 200 μm. This corresponds to a pwv of 0.18 mm for DOME C. At 350 μm, for 50% of time at DOME C (CCAT) the transmission is around 55% (25%). This corresponds to a pwv of 0.22 mm for DOME C. These results show that DOME C is one of the best observing sites on Earth for submm-astronomy with respect to high atmospheric transmission over long time periods.

We present preliminary results of the measurements of sky transparency conducted at Dome C during the winter 2008. Using MOLIERE modeling, we estimate a low precipitable water vapour content above Concordia station, which is very promising for future submillimetre wave observations on the Antarctic Plateau.

ArTeMiS is a bolometer camera that will be installed at the APEX submillimeter telescope in Chile in 2010. This instrument will be a powerful tool for scientists with its three focal planes that will operate simultaneously in background limited conditions at 200, 350 and 450 microns (5760 pixels in total). A prototype called p-ArTeMiS has been tested at APEX in 2007 and thanks to its good performances, the team has been able to conduct scientific projects in star formation and on debris disks. This paper summarises the details of the ArTeMiS project, with a description of the detectors, the optics, the cryogenics and the electronics. We will also present the undergoing studies at CEA on detectors for the future submillimeter space missions.

Astronomical observations at sub-millimetre wavelengths are limited either by the angular resolution of the telescope or by the sensitivity and field of view of the detector array. New generation of radio telescopes, such as the APEX 12-m telescope on Chajnantor plateau in Chile, can overcome these limitations if they are equipped with large detector arrays made of thousands of sensitive bolometer pixels. Instrumentation developments undertaken at CEA and based on the all silicon technology of CEA/Leti are able to provide such large detector arrays. The ArTeMiS project at CEA Saclay, in partnership with IAS, IAP and CRTBT, consists in developing a 4000-pixel bolometer camera for ground-based telescopes that operates in atmospheric windows at 200–450 μm (Talvard et al. 2006, SPIE, 6275).

Preliminary site testing datasets suggest that Dome C in Antarctica is one of the best sites on Earth for astronomical observations in the 200 to 500-μm regime, i.e. for far-infrared (FIR) and submillimetre (submm) astronomy. We present an overview of potential science cases that could be addressed with a large telescope facility at Dome C. This paper also includes a presentation of the current knowledge about the site characterics in terms of atmospheric transmission, stability, sky noise and polar constraints on telescopes. Current and future site testing campaigns are finally described.

We present the results of spectral energy distribution analysis for 162 of the 405 sources reported in the SIMBA survey of Hill et al. (2005). The fits reveal source specific parameters including: the luminosity, mass, temperature, H2 number density, the surface density and the luminosity-to-mass ratio. Each of these parameters are examined with respect to the four classes of source present in the sample. Obvious luminosity and temperature distinctions exist between the mm-only cores and those cores with methanol maser and/or radio continuum emission, with the former cooler and less luminous than the latter. The evidence suggests that the mm-only cores are a precursor to the methanol maser in the formation of massive stars. The mm-only cores comprise two distinct populations distinguished by temperature. Analysis and conclusions about the nature of the cool-mm and warm-mm cores comprising the mm-only population are drawn.

We have conducted phase-reference VLBI observations of H2O and CH3OH masers toward two high-mass star forming regions, Sh 2-255 IR and AFGL 5142. In Sh 2-255 infrared water masers are aligned along a direction close to the orientation of a large scale H2 jet, tracing possibly shocked material in a precessing jet, or, alternatively, the disk-wind emerging from the disk atmosphere. In AFGL 5142 water masers trace expansion at the base of a protostellar jet, whilst methanol masers are more probably tracing infalling than outflowing gas. Our results suggest that water and methanol masers trace different kinematic structures in the circumstellar gas.

The CEA, in coordination with IPEV and LUAN, will prepare an experiment to study frost formation on surfaces in radiative cooling in the winter. This experiment has been shipped to be installed at Concordia before the 2007 winter period. It will be controlled from Concordia winterover personal, through PC server that will locally archive data from WEBcams and several local heat regulators. This experiment will be used to give recipes on the way to compensate with heaters the radiative cooling from the sky and maintain instrument surfaces at temperature just above icing conditions. The individual regulators proposed in this experiment will be usable as standalone ice protection systems for existing and future telescopes.

Submillimetre/TeraHertz (e.g. 200, 350, 450 μm) astronomy is the prime technique to unveil the birth and early evolution of a broad range of astrophysical objects. A major obstacle to carry out submm observations from ground is the atmosphere. Preliminary site testing and atmospheric transmission models tend to demonstrate that Dome C could offer the best conditions on Earth for submm/THz astronomy. The CAMISTIC project aims to install a filled bolometer-array camera with 16×16 pixels on IRAIT at Dome C and explore the 200-μm windows for potential ground-based observations.

We present a multi-wavelength (NIR to radio) and multi-scale (1 AU to 10 pc) study of the S255–S257 complex of young high-mass (proto)stars. The complex consists of two evolved HII regions and a molecular gas filament in which new generations of high mass stars form. Four distinct regions are identified within this dusty filament: a young NIR/optical source cluster, a massive protostar binary, a (sub)millimetre continuum and molecular clump in global collapse and a reservoir of cold gas. Interestingly, the massive binary protostellar system is detected through methanol maser and mid-IR emission at the interface between the NIR cluster and the cold gas filament. The collapsing clump is located to the north of the NIR cluster and hosts a young high-mass star associated with an outflow that is observed in mid-IR, methanol maser and radio emission. We interpret this anatomy as the possible result of triggered star formation, starting with the formation of two HII regions, followed by the compression of a molecular gas filament in which a first generation of high-mass stars forms (the NIR cluster), which then triggers the formation of high mass protostars in its near environment (the massive protostellar binary). The global collapse of the northern clump might be due to both the expansion of the HII regions that squashes the filament. In conclusion, we witness the formation of four generations of clusters of high-mass stars in S255–S257.