An Algorithm for Preferential Selection of Spectroscopic Targets in LEGUE

TL;DR

The paper presents a versatile target selection algorithm designed for large astronomical surveys, balancing uniformity and prioritization, specifically tailored for the LEGUE survey's Galactic halo observations.

Contribution

It introduces a general, adaptable target selection algorithm optimized for surveys with more candidates than available observation slots, exemplified by its application to LEGUE.

Findings

Successfully implemented for LEGUE's Galactic halo survey

Balances uniform sampling and target prioritization

Demonstrates flexibility with different emphasis functions

Abstract

We describe a general target selection algorithm that is applicable to any survey in which the number of available candidates is much larger than the number of objects to be observed. This routine aims to achieve a balance between a smoothly-varying, well-understood selection function and the desire to preferentially select certain types of targets. Some target-selection examples are shown that illustrate different possibilities of emphasis functions. Although it is generally applicable, the algorithm was developed specifically for the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) survey that will be carried out using the Chinese Guo Shou Jing Telescope. In particular, this algorithm was designed for the portion of LEGUE targeting the Galactic halo, in which we attempt to balance a variety of science goals that require stars at fainter magnitudes than can be completely sampled by LAMOST. This algorithm has been implemented for the halo portion of the LAMOST pilot survey, which began in October 2011.