Hwang, Ho Seong, Geller, Margaret J., Kurtz, Michael J., Dell'Antonio, Ian P., and Fabricant, Daniel G. 2012. "SHELS: Optical Spectral Properties of WISE 22 μm Selected Galaxies." The Astrophysical Journal 758:25. https://doi.org/10.1088/0004-637X/758/1/25
We use a dense, complete redshift survey, the Smithsonian Hectospec Lensing Survey (SHELS), covering a 4 deg2 region of a deep imaging survey, the Deep Lens Survey (DLS), to study the optical spectral properties of Wide-field Infrared Survey Explorer (WISE) 22 μm selected galaxies. Among 507 WISE 22 μm selected sources with (S/N)22 μm >= 3 (≈S 22 μm >~ 2.5 mJy), we identify the optical counterparts of 481 sources (~98%) at R >~ 2.5 mJy), we identify the optical counterparts of 481 sources (~98%) at R >~ 2.5 mJy), we identify the optical counterparts of 481 sources (~98%) at R >~ 2.5 mJy), we identify the optical counterparts of 481 sources (~98%) at R 8(L &sun;) ) IR12(L &sun;). Most 22 μm selected galaxies are dusty star-forming galaxies with a small (<1.5) 4000 Å break. The stacked spectra of the 22 μm selected galaxies binned in IR luminosity show that the strength of the O III] line relative to Hβ grows with increasing IR luminosity. The optical spectra of the 22 μm selected galaxies also show that there are some (~2.8%) unusual galaxies with very strong Ne III] λ3869, 3968 emission lines that require hard ionizing radiation such as active galactic nuclei (AGNs) or extremely young massive stars. The specific star formation rates (sSFRs) derived from the 3.6 and 22 μm flux densities are enhanced if the 22 μm selected galaxies have close late-type neighbors. The sSFR distribution of the 22 μm selected galaxies containing AGNs is similar to the distribution for star-forming galaxies without AGNs. We identify 48 dust-obscured galaxy candidates with large (gsim 1000) mid-IR to optical flux density ratio. The combination of deep photometric and spectroscopic data with WISE data suggests that WISE can probe the universe to z ~ 2.