eBOSS Target Selection


eBOSS is the cosmology component of SDSS-IV, see Blanton et al. 2017. A detailed description of the survey is given in the eBOSS overview paper. The program targets luminous red galaxies (LRGs), quasars (QSOs), and emission line galaxies (ELGs) to measure baryon acoustic oscillations in the clustering of matter.


eBOSS covers several thousand square degrees within the BOSS footprint, targeting LRGs described in Prakash et al 2016, quasars described in Myers et al 2016 and ELGs described in Raichoor et al 2017 and Comparat et al. 2016.

eBOSS also encompasses two sub-programs to obtain spectra of variability-selected objects (TDSS) described in Morganson et al. 2015 and MacLeod et al. 2018, and X-ray detected objects (SPIDERS) that are described in more detail in Clerc et al 2016 and Dwelly et al 2017.

SEQUELS served both as a pilot program for the eBOSS survey of SDSS-IV and as a stand-alone science program. SEQUELS is part of the SDSS DR13 and is documented in Dawson et al. 2016.

Target Selection

The eBOSS footprint covers both the SGC and the NGC. For each class of targets, you will find a link to the corresponding page in this section.

LRGs are selected to extend the BOSS LRG redshift coverage, yielding a median redshift around 0.7. LRGs in were selected using a combination of SDSS imaging and WISE photometry.

ELGs are selected to cover the redshift range 0.7 < z < 1.1. The DECaLS photometry was used to identify the targets using a color selection in grz.

QSOs represent a combination of targets selected as Lyman-α forest QSOs and lower-redshift objects that serve as direct tracers of the density field at redshifts 1 < z < 2.
Lyman-α forest QSOs are themselves a compilation of known BOSS targets that have been selected for re-observation, and new targets selected from variability methods.

SPIDERS (SPectroscopic IDentifcation of ERosita Sources) is an SDSS-IV program that runs in parallel to eBOSS and TDSS. This page links to the X-ray survey webpage of the Max-Planck institute for extraterrestrial physics where SPIDERS was designed.

The Time-Domain Spectroscopic Survey (TDSS) is SDSS-IV eBOSS subprogram to systematically obtain follow-up spectra of ~200,000 photometrically time-variable sources. Target selection for TDSS in SDSS-IV is detailed in Morganson et al. 2015 and MacLeod et al. 2018.


SDSS-IV, Blanton et al. 2017

SPIDERS clusters, Clerc et al 2016

eBOSS ELG redshifts, Comparat et al. 2016

eBOSS overview, Dawson et al. 2016

SPIDERS AGN, Dwelly et al 2017

TDSS repeat spectroscopy selections, MacLeod et al. 2018

eBOSS LRG selection, Prakash et al 2016

TDSS PS1/SDSS variables selection, Morganson et al. 2015

eBOSS QSO selection, Myers et al 2016

Palanque Delabrouille et al. 2016

eBOSS ELG selection, Raichoor et al 2017