The physics and demographics of type 2 quasars remain poorly understood , and new samples of such objects selected in a variety of ways can give insight into their physical properties , evolution , and relationship to their host galaxies .
We present a sample of 2758 type 2 quasars at z \la 1 from the SDSS-III/BOSS spectroscopic database , selected on the basis of their emission-line properties .
We probe the luminous end of the population by requiring the rest-frame equivalent width of [ O III ] to be > 100 Å .
We distinguish our objects from star-forming galaxies and type 1 quasars using line widths , standard emission line ratio diagnostic diagrams at z < 0.52 and detection of [ Ne V ] \lambda 3426Å at z > 0.52 .
The majority of our objects have [ O III ] luminosities in the range 1.2 \times 10 ^ { 42 } -3.8 \times 10 ^ { 43 } { erg s ^ { -1 } } and redshifts between 0.4 and 0.65 .
Our sample includes over 400 type 2 quasars with incorrectly measured redshifts in the BOSS database ; such objects often show kinematic substructure or outflows in the [ O III ] line .
The majority of the sample has counterparts in the WISE survey , with median infrared luminosity \nu L _ { \nu } [ 12 \micron ] = 4.2 \times 10 ^ { 44 } { erg s ^ { -1 } } .
Only 34 per cent of the newly identified type 2 quasars would be selected by infrared color cuts designed to identify obscured active nuclei , highlighting the difficulty of identifying complete samples of type 2 quasars .
We make public the multi-Gaussian decompositions of all [ O III ] profiles for the new sample and for 568 type 2 quasars from SDSS I/II , together with non-parametric measures of the [ O III ] line profile shapes .
We also identify over 600 candidate double-peaked [ O III ] profiles .