VISIONS is an ESO public survey of five nearby (d < 500 pc) star-forming molecular cloud complexes that are canonically associated with the constellations of Chamaeleon, Corona Australis, Lupus, ...Ophiuchus, and Orion. The survey was carried out with VISTA, using VIRCAM, and collected data in the near-infrared passbands J, H, and Ks. With a total on-sky exposure time of 49.4 h VISIONS covers an area of 650 deg\(^2\), and it was designed to build an infrared legacy archive similar to that of 2MASS. Taking place between April 2017 and March 2022, the observations yielded approximately 1.15 million images, which comprise 19 TB of raw data. The observations are grouped into three different subsurveys: The wide subsurvey comprises shallow, large-scale observations and has visited the star-forming complexes six times over the course of its execution. The deep subsurvey of dedicated high-sensitivity observations has collected data on the areas with the largest amounts of dust extinction. The control subsurvey includes observations of areas of low-to-negligible dust extinction. Using this strategy, the VISIONS survey offers multi-epoch position measurements, is able to access deeply embedded objects, and provides a baseline for statistical comparisons and sample completeness. In particular, VISIONS is designed to measure the proper motions of point sources with a precision of 1 mas/yr or better, when complemented with data from VHS. Hence, VISIONS can provide proper motions for sources inaccessible to Gaia. VISIONS will enable addressing a range of topics, including the 3D distribution and motion of embedded stars and the nearby interstellar medium, the identification and characterization of young stellar objects, the formation and evolution of embedded stellar clusters and their initial mass function, as well as the characteristics of interstellar dust and the reddening law.
Since 2005 ESO has been working with its community and industry to develop an extremely large optical/infrared telescope. ESO's Extremely Large Telescope, or ELT for short, is a revolutionary ...ground-based telescope that will have a 39-metre main mirror and will be the largest visible and infrared light telescope in the world. To address specific topics that are needed for the science operations and calibrations of the telescope, thirteen specific working groups were created to coordinate the effort between ESO, the instrument consortia, and the wider community. We describe here the goals of these working groups as well as their achievements so far.
3D shape of Orion A from Gaia DR2 Grossschedl, Josefa E; Alves, Joao; Meingast, Stefan ...
arXiv.org,
08/2018
Paper, Journal Article
Odprti dostop
We use the \(\mathit{Gaia}\) DR2 distances of about 700 mid-infrared selected young stellar objects in the benchmark giant molecular cloud Orion A to infer its 3D shape and orientation. We find that ...Orion A is not the fairly straight filamentary cloud that we see in (2D) projection, but instead a cometary-like cloud oriented toward the Galactic plane, with two distinct components: a denser and enhanced star-forming (bent) Head, and a lower density and star-formation quieter \(\sim\)75 pc long Tail. The true extent of Orion A is not the projected \(\sim\)40 pc but \(\sim\)90 pc, making it by far the largest molecular cloud in the local neighborhood. Its aspect ratio (\(\sim\)30:1) and high column-density fraction (\(\sim45\%\)) make it similar to large-scale Milky Way filaments ("bones"), despite its distance to the galactic mid-plane being an order of magnitude larger than typically found for these structures.
MICADO will be the first-light wide-field imager for the European Extremely Large Telescope (E-ELT) and will provide difiraction limited imaging (7mas at 1.2mm) over a ~53 arcsecond field of view. In ...order to support various consortium activities we have developed a first version of SimCADO: an instrument simulator for MICADO. SimCADO uses the results of the detailed simulation efforts conducted for each of the separate consortium-internal work packages in order to generate a model of the optical path from source to detector readout. SimCADO is thus a tool to provide scientific context to both the science and instrument development teams who are ultimately responsible for the final design and future capabilities of the MICADO instrument. Here we present an overview of the inner workings of SimCADO and outline our plan for its further development.
One of the least understood processes in astrophysics is the formation of planetesimals from molecules and dust within protoplanetary disks. In fact, current methods have strong limitations when it ...comes to model the full dynamics in this phase of planet formation, where small dust aggregates collide and grow into bigger clusters. That is why microgravity experiments of the phenomena involved are important to reveal the underlying physics. Because previous experiments had some limitations, in particular short durations and constrained dimensions, a new mission to study the very first stages of planet formation is proposed here. This mission, called Magrathea, is focused on creating the best conditions for developing these experiments, using a satellite with a 6 \(m^3\) test chamber. During the mission 28 experiments are performed using different dust compositions, sizes and shapes, to better understand under which conditions dust grains stick and aggregate. Each experiment should last up to one month, with relative collision velocities of up to 5 mm/s, and initial dust sizes between 1 \(\mu\)m and 1 mm. At least \(10^6\) collisions per experiment should be recorded, to provide statistically significant results. Based on the scientific objectives and requirements, a preliminary analysis of the payload instrumentation is performed. From that a conceptual mission and spacecraft design is developed, together with a first approach to mission programmatic and risk analysis. The solution reached is a 1000 kg spacecraft, set on a 800 km Sun-synchronous orbit, with a total mission cost of around 438 MEuros.
MICADO will enable the ELT to perform diffraction limited near-infrared observations at first light. The instrument's capabilities focus on imaging (including astrometric and high contrast) as well ...as single object spectroscopy. This contribution looks at how requirements from the observing modes have driven the instrument design and functionality. Using examples from specific science cases, and making use of the data simulation tool, an outline is presented of what we can expect the instrument to achieve.
