The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: quasar target selection

Adam D. Myers, Nathalie Palanque-Delabrouille, Abhishek Prakash, Isabelle Pâris, Christophe Yeche, Kyle S. Dawson, Jo Bovy, Dustin Lang, David J. Schlegel, Jeffrey A. Newman, Patrick Petitjean, Jean Paul Kneib, Pierre Laurent, Will J. Percival, Ashley J. Ross, Hee-Jong Seo, Jeremy L. Tinker, Eric Armengaud, Joel Brownstein, Etienne BurtinZheng Cai, Johan Comparat, Mansi Kasliwal, Shrinivas R. Kulkarni, Russ Laher, David Levitan, Cameron K. McBride, Ian D. McGreer, Adam A. Miller, Peter Nugent, Eran Ofek, Graziano Rossi, John Ruan, Donald P. Schneider, Branimir Sesar, Alina Streblyanska, Jason Surace

Research output: Contribution to journalArticlepeer-review

188 Downloads (Pure)


As part of the Sloan Digital Sky Survey (SDSS) 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 deg2. First, a "CORE" quasar sample will combine the 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 deg−2 quasars at redshifts 0.9 < z < 2.2 and ~7 deg−2z > 2.1 quasars. Second, a selection based on variability in multi-epoch imaging from the Palomar Transient Factory should recover an additional ~3–4 deg−2z > 2.1 quasars 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 eBOSS quasars atz > 2.1 will be used to improve BAO measurements in the Lyα 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 for more than 800,000 quasars.
Original languageEnglish
Article number27
JournalThe Astrophysical Journal Supplement Series
Issue number2
Publication statusPublished - 31 Dec 2015


  • astro-ph.CO
  • astro-ph.GA
  • catalogs
  • cosmology: observations
  • galaxies: distances and redshifts
  • galaxies: photometry
  • methods: data analysis
  • quasars: general
  • RCUK
  • STFC


Dive into the research topics of 'The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: quasar target selection'. Together they form a unique fingerprint.

Cite this