Year: 2020
Type: article
Abstract: Context. Several new multi-object spectrographs are currently planned or under construction that are capable of observing thousands of Galactic and extragalactic objects simultaneously. Aims. In this paper we present a probabilistic fibre-to-target assignment algorithm that takes spectrograph targeting constraints into account and is capable of dealing with multiple concurrent surveys. We present this algorithm using the 4-m Multi-Object Spectroscopic Telescope (4MOST) as an example. Methods. The key idea of the proposed algorithm is to assign probabilities to fibre-target pairs. The assignment of probabilities takes the fibre positioner’s capabilities and constraints into account. Additionally, these probabilities include requirements from surveys and take the required exposure time, number density variation, and angular clustering of targets across each survey into account. The main advantage of a probabilistic approach is that it allows for accurate and easy computation of the target selection function for the different surveys, which involves determining the probability of observing a target, given an input catalogue. Results. The probabilistic fibre-to-target assignment allows us to achieve maximally uniform completeness within a single field of view. The proposed algorithm maximises the fraction of successfully observed targets whilst minimising the selection bias as a function of exposure time. In the case of several concurrent surveys, the algorithm maximally satisfies the scientific requirements of each survey and no specific survey is penalised or prioritised. Conclusions. The algorithm presented is a proposed solution for the 4MOST project that allows for an unbiased targeting of many simultaneous surveys. With some modifications, the algorithm may also be applied to other multi-object spectroscopic surveys.
Source: Astronomy and Astrophysics
Authors: E. Tempel, P. Norberg, T. Tuvikene, T. Bensby, C. Chiappini, N. Christlieb, M.-R. L. Cioni, J. Comparat, L. J. M. Davies, G. Guiglion, A. Koch, G. Kordopatis, M. Krumpe, J. Loveday, A. Merloni, G. Micheva, I. Minchev, B. F. Roukema, J. G. Sorce, E. Starkenburg, J. Storm, E. Swann, W. F. Thi, G. Traven, R. S. de Jong
Institutions: Tartu Observatory, University of Tartu, Durham University, Lund University, Leibniz Institute for Astrophysics Potsdam, Heidelberg University, Max Planck Institute for Extraterrestrial Physics, The University of Western Australia, International Centre for Radio Astronomy Research, Centre National de la Recherche Scientifique, Université Côte d'Azur, Lagrange Laboratory, Observatoire de la Côte d’Azur, University of Sussex, Lyon 1 Université, Nicolaus Copernicus University, Centre de Recherche Astrophysique de Lyon, University of Portsmouth
Language: English
Subfield: Instrumentation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: Royal Society, European Commission, Deutsche Forschungsgemeinschaft, Svenska Forskningsrådet Formas, Eesti Teadusagentuur, Deutsches Zentrum für Luft- und Raumfahrt, Knut och Alice Wallenbergs Stiftelse, Vetenskapsrådet, Ministerstwo Edukacji i Nauki, European Southern Observatory, Science and Technology Facilities Council, European Research Council, European Regional Development Fund
Awards: G1033536461, G1110427842, G1862865938, G198694327, The role of dark matter filaments in large-scale structure and assembly of galaxies, G4221417635, G4329979236, G434337789, Integral field spectroscopy of galaxies in the cosmic environment, G4772328477, G4795087365, G4834903470, G4930006217, G5146631217, G5602157879, G6075447204, G6147091739, Galaxy evolution in the hierarchical Universe, G653891685, G6570372938, The star formation history of the Milky Way thick disk, G7500481665, G7956055077, Durham Astronomy Consolidated Grant 2017-2020, G837177648
OpenAlex ID: W3001407244