A 2500 deg2 CMB Lensing Map from Combined South Pole Telescope and Planck Data
Bleem, L. E.; Stark, A. A.; George, E. M.; Reichardt, C. L.; Benson, B. A.; Carlstrom, J. E.; Chang, C. L.; Cho, H. -M.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Dobbs, M. A.; Halverson, N. W.; Harrington, N. L.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Knox, L.; Lee, A. T.; Leitch, E. M.; Luong-Van, D.; McMahon, J. J.; Meyer, S. S.; Mocanu, L. M.; Mohr, J. J.; Padin, S.; Pryke, C.; Ruhl, J. E.; Schaffer, K. K.; Shirokoff, E.; Staniszewski, Z.; Story, K. T.; Vanderlinde, K.; Vieira, J. D.; Williamson, R.; Zahn, O.; Marrone, D. P.; Natoli, T.; Chown, R.; Everett, W. B.; Sayre, J. T.; Manzotti, A.; Omori, Y.; Aylor, K.; Simard, G.; Baxter, E. J.
Canada, United States, Germany, Australia
Abstract
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 {C}Lφ φ , 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, {C}Lφ G, between the SPT+Planck lensing map and Wide-field Infrared Survey Explorer (WISE) galaxies. We fit {C}Lφ G to a power law of the form {p}L=a{(L/{L}0)}-b with a, L 0, and b fixed, and find {η }φ G={C}Lφ G/{p}L={0.94}-0.04+0.04, which is marginally lower, but in good agreement with {η }φ G={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.