A direct measurement of the linear bias of mid-infrared-selected quasars at z ≈ 1 using cosmic microwave background lensing

J. E. Geach, R. C. Hickox, L. E. Bleem, M. Brodwin, G. P. Holder, K. A. Aird, B. A. Benson, S. Bhattacharya, J. E. Carlstrom, C. L. Chang, H. M. Cho, T. M. Crawford, A. T. Crites, T. De Haan, M. A. Dobbs, J. Dudley, E. M. George, K. N. Hainline, N. W. Halverson, W. L. HolzapfelS. Hoover, Z. Hou, J. D. Hrubes, R. Keisler, L. Knox, A. T. Lee, E. M. Leitch, M. Lueker, D. Luong-Van, D. P. Marrone, J. J. McMahon, J. Mehl, S. S. Meyer, M. Millea, J. J. Mohr, T. E. Montroy, A. D. Myers, S. Padin, T. Plagge, C. Pryke, C. L. Reichardt, J. E. Ruhl, J. T. Sayre, K. K. Schaffer, L. Shaw, E. Shirokoff, H. G. Spieler, Z. Staniszewski, A. A. Stark, K. T. Story, A. Van Engelen, K. Vanderlinde, J. D. Vieira, R. Williamson, O. Zahn

Research output: Contribution to journalArticlepeer-review


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 deg2. 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.

Original languageEnglish (US)
Article numberL41
JournalAstrophysical Journal Letters
Issue number2
StatePublished - Oct 20 2013
Externally publishedYes


  • cosmology: observations

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'A direct measurement of the linear bias of mid-infrared-selected quasars at z ≈ 1 using cosmic microwave background lensing'. Together they form a unique fingerprint.

Cite this