An optimised tiling pattern for multi-object spectroscopic surveys: application to the 4MOST survey. (arXiv:2007.03307v1 [astro-ph.IM])
<a href="http://arxiv.org/find/astro-ph/1/au:+Tempel_E/0/1/0/all/0/1">E. Tempel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tuvikene_T/0/1/0/all/0/1">T. Tuvikene</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Muru_M/0/1/0/all/0/1">M. M. Muru</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stoica_R/0/1/0/all/0/1">R. S. Stoica</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bensby_T/0/1/0/all/0/1">T. Bensby</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chiappini_C/0/1/0/all/0/1">C. Chiappini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Christlieb_N/0/1/0/all/0/1">N. Christlieb</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cioni_M/0/1/0/all/0/1">M.-R. L. Cioni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Comparat_J/0/1/0/all/0/1">J. Comparat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Feltzing_S/0/1/0/all/0/1">S. Feltzing</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hook_I/0/1/0/all/0/1">I. Hook</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koch_A/0/1/0/all/0/1">A. Koch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kordopatis_G/0/1/0/all/0/1">G. Kordopatis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krumpe_M/0/1/0/all/0/1">M. Krumpe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Loveday_J/0/1/0/all/0/1">J. Loveday</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Minchev_I/0/1/0/all/0/1">I. Minchev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Norberg_P/0/1/0/all/0/1">P. Norberg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Roukema_B/0/1/0/all/0/1">B. F. Roukema</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sorce_J/0/1/0/all/0/1">J. G. Sorce</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Storm_J/0/1/0/all/0/1">J. Storm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Swann_E/0/1/0/all/0/1">E. Swann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Taylor_E/0/1/0/all/0/1">E. N. Taylor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Traven_G/0/1/0/all/0/1">G. Traven</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Walcher_C/0/1/0/all/0/1">C. J. Walcher</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jong_R/0/1/0/all/0/1">R. S. de Jong</a>
Large multi-object spectroscopic surveys require automated algorithms to
optimise their observing strategy. One of the most ambitious upcoming
spectroscopic surveys is the 4MOST survey. The 4MOST survey facility is a
fibre-fed spectroscopic instrument on the VISTA telescope with a large enough
field of view to survey a large fraction of the southern sky within a few
years. Several Galactic and extragalactic surveys will be carried out
simultaneously, so the combined target density will strongly vary. In this
paper, we describe a new tiling algorithm that can naturally deal with the
large target density variations on the sky and which automatically handles the
different exposure times of targets. The tiling pattern is modelled as a marked
point process, which is characterised by a probability density that integrates
the requirements imposed by the 4MOST survey. The optimal tilling pattern with
respect to the defined model is estimated by the tiles configuration that
maximises the proposed probability density. In order to achieve this
maximisation a simulated annealing algorithm is implemented. The algorithm
automatically finds an optimal tiling pattern and assigns a tentative sky
brightness condition and exposure time for each tile, while minimising the
total execution time that is needed to observe the list of targets in the
combined input catalogue of all surveys. Hence, the algorithm maximises the
long-term observing efficiency and provides an optimal tiling solution for the
survey. While designed for the 4MOST survey, the algorithm is flexible and can
with simple modifications be applied to any other multi-object spectroscopic
survey.
Large multi-object spectroscopic surveys require automated algorithms to
optimise their observing strategy. One of the most ambitious upcoming
spectroscopic surveys is the 4MOST survey. The 4MOST survey facility is a
fibre-fed spectroscopic instrument on the VISTA telescope with a large enough
field of view to survey a large fraction of the southern sky within a few
years. Several Galactic and extragalactic surveys will be carried out
simultaneously, so the combined target density will strongly vary. In this
paper, we describe a new tiling algorithm that can naturally deal with the
large target density variations on the sky and which automatically handles the
different exposure times of targets. The tiling pattern is modelled as a marked
point process, which is characterised by a probability density that integrates
the requirements imposed by the 4MOST survey. The optimal tilling pattern with
respect to the defined model is estimated by the tiles configuration that
maximises the proposed probability density. In order to achieve this
maximisation a simulated annealing algorithm is implemented. The algorithm
automatically finds an optimal tiling pattern and assigns a tentative sky
brightness condition and exposure time for each tile, while minimising the
total execution time that is needed to observe the list of targets in the
combined input catalogue of all surveys. Hence, the algorithm maximises the
long-term observing efficiency and provides an optimal tiling solution for the
survey. While designed for the 4MOST survey, the algorithm is flexible and can
with simple modifications be applied to any other multi-object spectroscopic
survey.
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