An Efficient Targeting Strategy for Multiobject Spectrograph Surveys: the Sloan Digital Sky Survey “Tiling” Algorithm

By M. Blanton, Huan Lin, Robert Lupton, F. M. Maley, Neal E. Young, Idit Zehavi, J. Loveday. 2001

491 citations recorded by the source corpus.

Large surveys using multiobject spectrographs require automated methods for deciding how to efficiently point observations and how to assign targets to each pointing. The Sloan Digital Sky Survey (SDSS) will observe around 106 spectra from targets distributed over an area of about 10,000 deg2, using a multiobject fiber spectrograph that can simultaneously observe 640 objects in a circular field of view (referred to as a "tile") 1.°49 in radius. No two fibers can be placed closer than 55″ during the same observation; multiple targets closer than this distance are said to "collide." We present here a method of allocating fibers to desired targets given a set of tile centers that includes the effects of collisions and that is nearly optimally efficient and uniform. Because of large-scale structure in the galaxy distribution (which form the bulk of the SDSS targets), a naive covering of the sky with equally spaced tiles does not yield uniform sampling. Thus, we present a heuristic for perturbing the centers of the tiles from the equally spaced distribution that provides more uniform completeness. For the SDSS sample, we can attain a sampling rate of greater than 92% for all targets, and greater than 99% for the set of targets that do not collide with each other, with an efficiency greater than 90% (defined as the fraction of available fibers assigned to targets). The methods used here may prove useful to those planning other large surveys.

Subfields: Astronomy and Astrophysics, Environmental Engineering, Instrumentation

View Paper: https://www.semanticscholar.org/paper/2277e7921a579051be4207d1b57000a38838342b

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Citations in the corpus

The 6dF Galaxy Survey: Samples, observational techniques and the first data release (2004, background): “These include the precise determination of the luminosity function of galaxies (e.g. Folkes et al. 1999; Blanton et al. 2001; Cole et al. 2001; Cross et al. 2001; Madgwick et al. 2002; Norberg et al. 2002; Blanton et al. 2003), the space density of nearby rich galaxy clusters (De Propris et al.…”
The distribution of stellar mass in the low‐redshift Universe (2009, methodology): “Spectroscopic fibres are assigned to the targets using an efficient tiling algorithm designed to optimise completeness (Blanton et al. 2003).”
The Velocity Dispersion Function of Early-Type Galaxies (2003, unknown): “The luminosity function of the entire SDSS sample, φtot(L), has been estimated by Blanton et al. (2003).”
Detection of Cosmic Magnification with the Sloan Digital Sky Survey (2005, unknown): “…(z ≤ 2.5) quasars from the stellar locus in 4 dimensional color space, producing a catalog of 225,000 quasars down to a limiting magnitude of 21 in the g band with greater efficiency and completeness than the SDSS spectroscopic targeting algorithm (Richards et al. 2002; Blanton et al. 2003).”
Detection of large-scale intrinsic ellipticity—density correlation from the Sloan Digital Sky Survey and implications for weak lensing surveys (2005, methodology): “The random points were assigned absolute magnitudes drawn from a distribution consistent with the real sample, and random redshifts were assigned for a given magnitude given the selection function φ(M |z) from Blanton et al. (2003c).”
Cosmological constraints from the clustering of the Sloan Digital Sky Survey DR7 luminous red galaxies (vol 404, pg 60, 2010) (2009, background): “The tiling algorithm ensures nearly complete samples (Blanton et al. 2003a).”
Colors, Magnitudes, and Velocity Dispersions in Early-Type Galaxies: Implications for Galaxy Ages and Metallicities (2004, background): “…and calibration; Lupton et al. (2001) for a discussion of the photometric data reduction pipeline; Pier et al. (2003) for the astrometric calibrations; Blanton et al. (2003) for details of the tiling algorithm; Strauss et al. (2002) and Eisenstein et al. (2001) for details of the target selection.”
The Sloan Digital Sky Survey View of the Palomar-Green Bright Quasar Survey (2005, methodology): “A tiling algorithm ensures uniformity and efficiency of the allocation of fibers to quasar candidates and other spectroscopic targets (Blanton et al. 2003).”
Detection of the Baryon Acoustic Peak in the Large-Scale Correlation Function of SDSS Luminous Red Galaxies (2005, methodology): “Targets are assigned to plug plates with a tiling algorithm that ensures nearly complete samples (Blanton et al. 2003a); observing each plate generates 640 spectra covering 3800Å to 9200Å with a resolution of 1800.”
Distributions of Galaxy Spectral Types in the Sloan Digital Sky Survey (2004, methodology): “The aperture magnitudes of all galaxies are initially k-corrected to redshift z = 0.1 using the code by Blanton et al. (2003b) version 1.16 prior to estimating the spectral types.”
The Environment of Active Galactic Nuclei in the Sloan Digital Sky Survey (2003, methodology): “The data are taken from the Early Data Release of the SDSS (see Stoughton et al. 2002; see also Blanton et al. 2003; Fukugita et al. 2003; Gunn et al. 1998; Hogg et al. 2001; Pier et al. 2003; Smith et al. 2002; Strauss et al. 2002).”
The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR14 quasar sample: First measurement of baryon acoustic oscillations between redshift 0.8 and 2.2 (2017, methodology): “Targets that pass the target selection algorithm, and for which there are no known good redshifts, are fed into a tiling algorithm (Blanton et al. 2003), that allocates spectroscopic fibers to targets within a 3 deg tile.”
Galaxy bimodality versus stellar mass and environment (2006, methodology): “For testing and calibration of the redshift errors, trainingset galaxies were not matched to themselves. c© 2006 RAS, MNRAS 000, 1–19 with (Ωm,ΩΛ)0 = (0.3,0.7) and H0 = 70 km s −1 Mpc−1, and; kr is the k-correction using the method of Blanton et al. (2003b)”
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: analysis of potential systematics (2012, background): “Each of these circles2 contains a unique set of targets and its area represents a ‘tile’ (see Blanton et al. 2003; Dawson et al., in preparation).”
Double-peaked Low-Ionization Emission Lines in Active Galactic Nuclei (2003, background): “The fibers subtend 300 on the sky, and approximately 80 of them are allocated to AGN candidates on each plate (Blanton et al. 2003).”
The Dependence on Environment of the Color-Magnitude Relation of Galaxies (2003, methodology): “…et al. 2001), calibration (Fukugita et al. 1996; Smith et al. 2002), spectroscopic target selection (Eisenstein et al. 2001; Strauss et al. 2002; Richards et al. 2002), spectroscopic fiber placement (Blanton et al. 2003a), and spectroscopic data reduction—is performed with automated SDSS software.”
The Broadband Optical Properties of Galaxies with Redshifts 0.02 < z < 0.22 (2002, unknown): “…counts on redshift in the survey, it is necessary to include the possibility that galaxy luminosities evolve; an approximation of the results of Blanton et al. (2003c) is ¼ 2:86 10 2 h3 Mpc 3 ; ð9Þ M ¼ 20:44 ; ð10Þ ¼ 1:05 ; ð11Þ Q ¼ 1:60 : ð12Þ That paper discusses the luminosity function and…”
A Galaxy Photometric Redshift Catalog for the Sloan Digital Sky Survey Data Release 6 (2007, methodology): “In this paper, we present a publicly available galaxy photometric redshift catalog for the Sixth Data Release (DR6) of the Sloan Digital Sky Survey (SDSS) imaging catalog (Blanton et al. 2003; Eisenstein et al. 2001; Gunn et al. 1998; Ivezić et al. 2004; Strauss et al. 2002; York et al. 2000).”
The Intermediate-Scale Clustering of Luminous Red Galaxies (2004, background): “We then find how luminous a galaxy would have to be to pass the LRG selection cut (this is a highly sensitive function of color) and integrate a hypothesized passively evolved luminosity function, following Blanton et al. (2003b), to find the number of galaxies.”