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Open Access Publications from the University of California

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

  • Author(s): Omori, Y
  • Chown, R
  • Simard, G
  • Story, KT
  • Aylor, K
  • Baxter, EJ
  • Benson, BA
  • Bleem, LE
  • Carlstrom, JE
  • Chang, CL
  • Cho, HM
  • Crawford, TM
  • Crites, AT
  • Haan, TD
  • Dobbs, MA
  • Everett, WB
  • George, EM
  • Halverson, NW
  • Harrington, NL
  • Holder, GP
  • Hou, Z
  • Holzapfel, WL
  • Hrubes, JD
  • Knox, L
  • Lee, AT
  • Leitch, EM
  • Luong-Van, D
  • Manzotti, A
  • Marrone, DP
  • McMahon, JJ
  • Meyer, SS
  • Mocanu, LM
  • Mohr, JJ
  • Natoli, T
  • Padin, S
  • Pryke, C
  • Reichardt, CL
  • Ruhl, JE
  • Sayre, JT
  • Schaffer, KK
  • Shirokoff, E
  • Staniszewski, Z
  • Stark, AA
  • Vanderlinde, K
  • Vieira, JD
  • Williamson, R
  • Zahn, O
  • et al.

© 2017. The American Astronomical Society. All rights reserved. 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.

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