Investigating Emission Line Galaxy Surveys with the Sloan Digital Sky
  Survey Telescope
  The Baryon Acoustic Oscillation (BAO) feature in the power spectrum of
galaxies provides a standard ruler to probe the accelerated expansion of the
Universe. The current surveys covering a comoving volume sufficient to unveil
the BAO scale are limited to redshift $z \lesssim 0.7$. In this paper, we study
several galaxy selection schemes aiming at building an emission-line-galaxy
(ELG) sample in the redshift range $0.6<z<1.7$, that would be suitable for
future BAO studies using the Baryonic Oscillation Spectroscopic Survey (BOSS)
spectrograph on the Sloan Digital Sky Survey (SDSS) telescope. We explore two
different colour selections using both the SDSS and the Canada France Hawai
Telescope Legacy Survey (CFHT-LS) photometry in the u, g, r, and i bands and
evaluate their performance selecting luminous ELG. From about 2,000 ELG, we
identified a selection scheme that has a 75 percent redshift measurement
efficiency. This result confirms the feasibility of massive ELG surveys using
the BOSS spectrograph on the SDSS telescope for a BAO detection at redshift
$z\sim1$, in particular the proposed eBOSS experiment, which plans to use the
SDSS telescope to combine the use of the BAO ruler with redshift space
distortions using emission line galaxies and quasars in the redshift
$0.6<z<2.2$.
