Selection functions of large spectroscopic surveys

Abstract

Context. Large spectroscopic surveys open the way to explore our Galaxy. In order to use the data from these surveys to understand the Galactic stellar population, we need to be sure that stars contained in a survey are a representative subset of the underlying population. Without the selection function taken into account, the results might reflect the properties of the selection function rather than those of the underlying stellar population. Aims. In this work, we introduce a method to estimate the selection function for a given spectroscopic survey. We apply this method to a large sample of public spectroscopic surveys. Methods. We apply a median division binning algorithm to bin observed stars in the colour-magnitude space. This approach produces lower uncertainties and lower biases of the selection function estimate as compared to traditionally used 2D-histograms. We run a set of simulations to verify the method and calibrate the one free parameter it contains. These simulations allow us to test the precision and accuracy of the method. Results. We produce and publish estimated values and uncertainties of selection functions for a large sample of public spectroscopic surveys. We publicly release the code used to produce the selection function estimates. Conclusions. The effect of the selection function on distance modulus and metallicity distributions of stars in surveys is important for surveys with small and largely inhomogeneous spatial coverage. For surveys with contiguous spatial coverage the effect of the selection function is almost negligible.

arXiv comment12 pages, 11 figures, 1 table

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Cited by in corpus (11)

• The Photometric Metallicity and Carbon Distributions of the Milky Way's Halo and Solar Neighborhood from S-PLUS Observations of SDSS Stripe 82
• Chemical Cartography. II. The Assembly History of the Galactic Stellar Halo Traced by Carbon-Enhanced Metal-Poor Stars
• Completeness of the Gaia-verse V: Astrometry and Radial Velocity sample selection functions in Gaia EDR3
• High- and Low-$\alpha$ Disk Stars Separate Dynamically at all Ages
• Dependence of Galactic Halo Kinematics on the Adopted Galactic Potential
• Insights into the Formation and Evolution History of the Galactic Disk System
• seestar: Selection functions for spectroscopic surveys of the Milky Way
• Using heritability of stellar chemistry to reveal the history of the Milky Way
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data I. Method validation
• Ensemble age inversions for large spectroscopic surveys
• A selection function toolbox for subsets of astronomical catalogues