As part of the Sloan Digital Sky Survey IV the extended Baryon Oscillation Spectroscopic Survey (eBOSS) will improve measurements of the cosmological distance scale by applying the Baryon Acoustic Oscillation (BAO) method to quasar samples. eBOSS will adopt two approaches to target quasars over 7500 sq. deg. First, a "CORE" quasar sample will combine optical selection in ugriz using a likelihood-based routine called XDQSOz, with a mid-IR-optical color-cut. eBOSS CORE selection (to g < 22 OR r < 22) should return ~ 70 quasars per sq. deg. at redshifts 0.9 < z < 2.2 and ~7 z > 2.1 quasars per sq. deg. Second, a selection based on variability in multi-epoch imaging from the Palomar Transient Factory should recover an additional ~3-4 z > 2.1 quasars per sq. deg. to g < 22.5. A linear model of how imaging systematics affect target density recovers the angular distribution of eBOSS CORE quasars over 96.7% (76.7%) of the SDSS North (South) Galactic Cap area. The eBOSS CORE quasar sample should thus be sufficiently dense and homogeneous over 0.9 < z < 2.2 to yield the first few-percent-level BAO constraint near z~1.5. eBOSS quasars at z > 2.1 will be used to improve BAO measurements in the Lyman-alpha Forest. Beyond its key cosmological goals, eBOSS should be the next-generation quasar survey, comprising > 500,000 new quasars and > 500,000 uniformly selected spectroscopically confirmed 0.9 < z < 2.2 quasars. At the conclusion of eBOSS, the SDSS will have provided unique spectra of over 800,000 quasars.
@article{arxiv.1508.04472,
title = {The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Quasar Target Selection},
author = {Adam D. Myers and Nathalie Palanque-Delabrouille and Abhishek Prakash and Isabelle Pâris and Christophe Yeche and Kyle S. Dawson and Jo Bovy and Dustin Lang and David J. Schlegel and Jeffrey A. Newman and Patrick Petitjean and Jean Paul Kneib and Pierre Laurent and Will J. Percival and Ashley J. Ross and Hee-Jong Seo and Jeremy L. Tinker and Eric Armengaud and Joel Brownstein and Etienne Burtin and Zheng Cai and Johan Comparat and Mansi Kasliwal and Shrinivas R. Kulkarni and Russ Laher and David Levitan and Cameron K. McBride and Ian D. McGreer and Adam A. Miller and Peter Nugent and Eran Ofek and Graziano Rossi and John Ruan and Donald P. Schneider and Branimir Sesar and Alina Streblyanska and Jason Surace},
journal= {arXiv preprint arXiv:1508.04472},
year = {2019}
}
Comments
25 pages, 21 figures, 6 tables, Accepted to ApJS after minor revisions and replaced with accepted version. Results unchanged