Curto A., Tucci M., Kunz M., Martínez-González E.
Instituto de Física de Cantabria, CSIC, Universidad de Cantabria, Avda. de los Castros s/n, Santander, Spain; Astrophysics Group, Cavendish Laboratory, Madingley Road, Cambridge, United Kingdom; Kavli Institute for Cosmology Cambridge, Madingley Road, Cambridge, United Kingdom; Département de Physique Théorique, Center for Astroparticle Physics, Université de Genève, 24 quai Ansermet, Genève 4, Switzerland; African Institute for Mathematical Sciences, 6 Melrose Road, Muizenberg, South Africa
Curto, A., Instituto de Física de Cantabria, CSIC, Universidad de Cantabria, Avda. de los Castros s/n, Santander, Spain, Astrophysics Group, Cavendish Laboratory, Madingley Road, Cambridge, United Kingdom, Kavli Institute for Cosmology Cambridge, Madingley Road, Cambridge, United Kingdom; Tucci, M., Département de Physique Théorique, Center for Astroparticle Physics, Université de Genève, 24 quai Ansermet, Genève 4, Switzerland; Kunz, M., Département de Physique Théorique, Center for Astroparticle Physics, Université de Genève, 24 quai Ansermet, Genève 4, Switzerland, African Institute for Mathematical Sciences, 6 Melrose Road, Muizenberg, South Africa; Martínez-González, E., Instituto de Física de Cantabria, CSIC, Universidad de Cantabria, Avda. de los Castros s/n, Santander, Spain
We characterize the cosmic infrared background (CIB)-lensing bispectrum which is one of the contributions to the three-point functions of cosmic microwave background (CMB) maps in harmonic space. We show that the CIB-lensing bispectrum has a considerable strength and that it can be detected with high significance in the Planck high-frequency maps. We also present forecasts of the contamination on different shapes of the primordial non-Gaussianity f<inf>nl</inf> parameter produced by the CIB-lensing bispectrum and by the extragalactic point sources bispectrum in the Planck high-resolution CMB anisotropy maps. The local, equilateral and orthogonal shapes are considered for 'raw' single-frequency (i.e. without applying any component separation technique) and foreground-reduced Planck temperaturemaps. The CIB-lensing correlation seems to mainly affect orthogonal shapes of the bispectrum-with Δf (ort) <inf>nl</inf> = -21 and -88 for the 143 and 217 GHz bands, respectively-while point sources mostly impact equilateral shapes, with Δf (eq) <inf>nl</inf> = 160, 54 and 60 at 100, 143 and 217 GHz. However, the results indicate that these contaminants do not induce any relevant bias on Planck f<inf>nl</inf> estimates when foreground-reduced maps are considered: using SEVEM for the component separation, we obtain Δf (ort) <inf>nl</inf> = 10.5 due to the CIB-lensing and Δf (eq) <inf>nl</inf> = 30.4 due to point sources, corresponding to 0.3σ and 0.45σ in terms of the Planck 2013 fnl uncertainty. The component separation technique is, in fact, able to partially clean the extragalactic source contamination and the bias is reduced for all the shapes. We have further developed singleand multiple-frequency estimators based on the Komatsu, Spergel & Wandelt formalism that can be implemented to efficiently detect this signal. © 2015 The Authors.