A Direct Measurement of the Linear Bias of Mid-infrared-selected Quasars at z ≈ 1 Using Cosmic Microwave Background Lensing

• Published in: The Astrophysical Journal
• Main Authors: Geach, J. E., Lueker, M., Padin, S., Vieira, J. D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Astronomical Society 2013
• Subjects: South Pole; South pole
• Online Access: https://authors.library.caltech.edu/42227/; https://authors.library.caltech.edu/42227/1/2041-8205_776_2_L41.pdf; https://authors.library.caltech.edu/42227/7/1307.1706v2.pdf; https://resolver.caltech.edu/CaltechAUTHORS:20131104-135724437

We measure the cross-power spectrum of the projected mass density as traced by the convergence of the cosmic microwave background lensing field from the South Pole Telescope (SPT) and a sample of Type 1 and 2 (unobscured and obscured) quasars at 〈z〉 ~ 1 selected with the Wide-field Infrared Survey Explorer, over 2500 deg^2. The cross-power spectrum is detected at ≈7σ, and we measure a linear bias b = 1.61 ± 0.22, consistent with clustering analyses. Using an independent lensing map, derived from Planck observations, to measure the cross-spectrum, we find excellent agreement with the SPT analysis. The bias of the combined sample of Type 1 and 2 quasars determined in this work is similar to that previously determined for Type 1 quasars alone; we conclude that obscured and unobscured quasars trace the matter field in a similar way. This result has implications for our understanding of quasar unification and evolution schemes.