A 2500 deg2 CMB Lensing Map from Combined South Pole Telescope and Planck Data

Y. Omori, R. Chown, G. Simard, K. T. Story, K. Aylor, E. J. Baxter, B. A. Benson, L. E. Bleem, J. E. Carlstrom, C. L. Chang, H. M. Cho, T. M. Crawford, A. T. Crites, T. De Haan, M. A. Dobbs, W. B. Everett, E. M. George, N. W. Halverson, N. L. Harrington, G. P. HolderZ. Hou, W. L. Holzapfel, J. D. Hrubes, L. Knox, A. T. Lee, E. M. Leitch, D. Luong-Van, A. Manzotti, D. P. Marrone, J. J. McMahon, S. S. Meyer, L. M. Mocanu, J. J. Mohr, T. Natoli, S. Padin, C. Pryke, C. L. Reichardt, J. E. Ruhl, J. T. Sayre, K. K. Schaffer, E. Shirokoff, Z. Staniszewski, A. A. Stark, K. Vanderlinde, J. D. Vieira, R. Williamson, O. Zahn

Research output: Contribution to journalArticle

25 Scopus citations


We present a cosmic microwave background (CMB) lensing map produced from a linear combination of South Pole Telescope (SPT) and Planck temperature data. The 150 GHz temperature data from the 2500 deg2 SPT-SZ survey is combined with the Planck 143 GHz data in harmonic space to obtain a temperature map that has a broader ℓ coverage and less noise than either individual map. Using a quadratic estimator technique on this combined temperature map, we produce a map of the gravitational lensing potential projected along the line of sight. We measure the auto-spectrum of the lensing potential CLφφ, and compare it to the theoretical prediction for a ΛCDM cosmology consistent with the Planck 2015 data set, finding a best-fit amplitude of 0.95-0.06+0.06(stat.)0.01+0.01(sys.). The null hypothesis of no lensing is rejected at a significance of 24σ. One important use of such a lensing potential map is in cross-correlations with other dark matter tracers. We demonstrate this cross-correlation in practice by calculating the cross-spectrum, CLφG, between the SPT+Planck lensing map and Wide-field Infrared Survey Explorer (WISE) galaxies. We fit CLφG to a power law of the form PL = a(L/L0)-b with a, L 0, and b fixed, and find ηφG = CLφG/PL = 0.94-0.04+0.04, which is marginally lower, but in good agreement with ηφG = 1.00-0.01+0.02, the best-fit amplitude for the cross-correlation of Planck-2015 CMB lensing and WISE galaxies over ∼67% of the sky. The lensing potential map presented here will be used for cross-correlation studies with the Dark Energy Survey, whose footprint nearly completely covers the SPT 2500 deg2 field.

Original languageEnglish (US)
Article number124
JournalAstrophysical Journal
Issue number2
StatePublished - Nov 10 2017


  • cosmic background radiation
  • gravitational lensing: weak
  • large-scale structure of universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Omori, Y., Chown, R., Simard, G., Story, K. T., Aylor, K., Baxter, E. J., Benson, B. A., Bleem, L. E., Carlstrom, J. E., Chang, C. L., Cho, H. M., Crawford, T. M., Crites, A. T., Haan, T. D., Dobbs, M. A., Everett, W. B., George, E. M., Halverson, N. W., Harrington, N. L., ... Zahn, O. (2017). A 2500 deg2 CMB Lensing Map from Combined South Pole Telescope and Planck Data. Astrophysical Journal, 849(2), [124]. https://doi.org/10.3847/1538-4357/aa8d1d