“WISE BOSS”: BOSS spectra of Mid-IR bright AGN


Photo of Nic Ross
Nic Ross
University of Edinburgh


Spectra of quasars selected from the WISE All-Sky Survey, selected to study the completeness of the BOSS main quasar sample and to enable studies of the dust obscuration of quasars

Finding Targets

An object whose ANCILLARY_TARGET2 value includes one or more of the bitmasks in the following table was targeted for spectroscopy as part of this ancillary target program. See SDSS bitmasks to learn how to use these values to identify objects in this ancillary target program.

Program (bit name) Bit number Target Description Number of Fibers Number of Unique Primary Objects
WISE_BOSS_QSO 14 Quasar identified in the WISE All-Sky Survey 21,647 20,808


The release of mid-infrared data from the WISE (Wide-field Infrared Survey Explorer) All-Sky survey (Wright et al. 2010) allows an enhanced selection of quasars that goes beyond the main BOSS quasar sample (Ross et al. 2012).

This ancillary target program used photometry from the WISE All-Sky Data Release catalog in combination with SDSS photometry to select a 12 µm flux-limited sample of quasars. These quasar spectra enable studies of the completeness of the main quasar sample, as well as exploration of dust obscuration of quasars.

Other science goals motivating this sample include: measurements of a wide range of quasar spectral energy distributions; constraints on the evolution of luminous AGN from cross-correlation clustering measurements; and further quantifying the selection function of the z > 2 BOSS Quasar Survey.

Target Selection

The WISE_BOSS_QSO class of target was selected for extended objects with:

  • iPSF < 20.2
  • W1 – W2 < 0.30
  • W1 < 2.0 + 0.667 * gPSF
  • rPSF – W2 > 2.0
  • W2 < 18.5
  • W3 > 10.3

The resulting sample peaks at redshift z ≈ 1.4. The WISE photometry is presented in Vega magnitudes.


Wright, E. L., et al. 2010, AJ, 140, 1868

Ross, N. P., et al. 2012, ApJS, 199, 3