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  • Christleib, Norbert, et al. (author)
  • 4MOST Consortium Survey 2: The Milky Way Halo High-Resolution Survey
  • 2019
  • In: Messenger. - 0722-6691. ; 175, s. 26-29
  • Journal article (other academic/artistic)abstract
    • We will study the formation history of the Milky Way, and the earliest phases of its chemical enrichment, with a sample of more than 1.5 million stars at high galactic latitude. Elemental abundances of up to 20 elements with a precision of better than 0.2 dex will be derived for these stars. The sample will include members of kinematically coherent substructures, which we will associate with their possible birthplaces by means of their abundance signatures and kinematics, allowing us to test models of galaxy formation. Our target catalogue is also expected to contain 30 000 stars at a metallicity of less than one hundredth that of the Sun. This sample will therefore be almost a factor of 100 larger than currently existing samples of metal-poor stars for which precise elemental abundances are available (determined from high-resolution spectroscopy), enabling us to study the early chemical evolution of the Milky Way in unprecedented detail.
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  • de Jong, R. S., et al. (author)
  • 4MOST : Project overview and information for the First Call for Proposals
  • 2019
  • In: The Messenger. - : European Southern Observatory. - 0722-6691. ; 175, s. 3-11
  • Journal article (other academic/artistic)abstract
    • We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under development for the four-metre-class Visible and Infrared Survey Telescope for Astronomy (VISTA) at Paranal. Its key specifications are: a large field of view (FoV) of 4.2 square degrees and a high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs (R = λ/Δλ ~ 6500), and 812 fibres transferring light to the high-resolution spectrograph (R ~ 20 000). After a description of the instrument and its expected performance, a short overview is given of its operational scheme and planned 4MOST Consortium science; these aspects are covered in more detail in other articles in this edition of The Messenger. Finally, the processes, schedules, and policies concerning the selection of ESO Community Surveys are presented, commencing with a singular opportunity to submit Letters of Intent for Public Surveys during the first five years of 4MOST operations.
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  • Guiglion, G., et al. (author)
  • 4MOST Survey Strategy Plan
  • 2019
  • In: Messenger. - 0722-6691. ; 175, s. 17-21
  • Journal article (other academic/artistic)abstract
    • The current status of and motivation for the 4MOST survey strategy, as developed by the Consortium science team, are presented here. Key elements of the strategy are described, such as sky coverage, number of visits and total exposure times in different parts of the sky, and how to deal with different observing conditions. The task of organising the strategy is not simple, with many different surveys that have vastly different target brightnesses and densities, sample completeness levels, and signal-to-noise requirements. We introduce here a number of concepts that we will use to ensure all surveys are optimised. Astronomers who are planning to submit a Participating Survey proposal are strongly encouraged to read this article and any relevant 4MOST Survey articles in this issue of The Messenger such that they can optimally complement and benefit from the planned surveys of the 4MOST Consortium.
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  • Walcher, C.~J., et al. (author)
  • 4MOST Scientific Operations
  • 2019
  • In: Messenger. - 0722-6691. ; 175, s. 12-16
  • Journal article (other academic/artistic)abstract
    • The 4MOST instrument is a multi-object spectrograph that will address Galactic and extragalactic science cases simultaneously by observing targets from a large number of different surveys within each science exposure. This parallel mode of operation and the survey nature of 4MOST require some distinct 4MOST- specific operational features within the overall operations model of ESO. The main feature is that the 4MOST Consortium will deliver, not only the instrument, but also contractual services to the user community, which is why 4MOST is also described as a facility. This white paper concentrates on information particularly useful to answering the forthcoming Call for Letters of Intent.
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  • Korn, Andreas J., et al. (author)
  • New Abundances for Old Stars – Atomic Diffusion at Work in NGC 6397
  • 2006
  • In: The Messenger. - 0722-6691. ; 125, s. 6-10
  • Research review (pop. science, debate, etc.)abstract
    • A homogeneous spectroscopic analysis of unevolved and evolved stars in the metal-poor globular cluster NGC 6397 with FLAMES-UVES reveals systematic trends of stellar surface abundances that are likely caused by atomic diffu-sion. This finding helps to understand, among other issues, why the lithium abundances of old halo stars are sig-nificantly lower than the abundance found to be produced shortly after the Big Bang.
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  • Primas, F., et al. (author)
  • Shaping ESO2020+ Together: Feedback from the Community Poll
  • 2015
  • In: The Messenger. - 0722-6691. ; 161, s. 6-14
  • Journal article (other academic/artistic)abstract
    • A thorough evaluation and prioritisation of the ESO science programme into the 2020+ timeframe took place under the auspices of a working group, comprising astronomers drawn from ESO’s advisory structure and from within ESO. This group reported to ESO’s Scientific Technical Committee, and to ESO Council, concluding the exercise with the publication of a report, “Science Priorities at ESO”. A community poll and a dedicated workshop, held in January 2015, formed part of the information gathering process. The community poll was designed to probe the demographics of the user community, its scientific interests, use of observing facilities and plans for use of future telescopes and instruments, its views on types of observing programmes and on the provision of data processing and archiving. A total of 1775 full responses to the poll were received and an analysis of the results is presented here. Foremost is the importance of regular observing programmes on all ESO observing facilities, in addition to Large Programmes and Public Surveys. There was also a strong community requirement for ESO to process and archive data obtained at ESO facilities. Other aspects, especially those related to future facilities, are more challenging to interpret because of biases related to the distribution of science expertise and favoured wavelength regime amongst the targeted audience. The results of the poll formed a fundamental component of the report and pro-vide useful data to guide the evolution of ESO’s science programme.
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