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Thomas Bensby. Profile photo.

Thomas Bensby

Senior lecturer

Thomas Bensby. Profile photo.

Probabilistic fibre-to-target assignment algorithm for multi-object spectroscopic surveys

Author

  • 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
Show all

Summary, in English

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.

Department/s

  • Lund Observatory - Has been reorganised
  • Department of Astronomy and Theoretical Physics - Has been reorganised
  • eSSENCE: The e-Science Collaboration

Publishing year

2020

Language

English

Publication/Series

Astronomy and Astrophysics

Volume

635

Document type

Journal article

Publisher

EDP Sciences

Topic

  • Astronomy, Astrophysics and Cosmology
  • Signal Processing

Keywords

  • Instrumentation: spectrographs
  • Methods: statistical
  • Surveys
  • Techniques: miscellaneous

Status

Published

Project

  • 4MOST - massive spectroscopic surveys of the Milky Way and the Universe

ISBN/ISSN/Other

  • ISSN: 0004-6361