Abstract
In this final short chapter we summarise the results of the thesis. The contamination from the intrinsic bispectrum generated by the non-linear effects generally leads to a small bias in the estimates of primordial non-Gaussianity. This is good news for the prospect of using CMB data to probe primordial non-Gaussianity, especially for experiments such as ESA Planck space telescope. While the precise answer depends on the terms included, the biases for local templates of non-Gaussianity are below the level of primordial \(f_\text {NL}\) detectable by the Planck satellite. The biases from the intrinsic bispectrum for other primordial templates, equilateral and orthogonal, also appear to be small. The intrinsic non-Gaussianity can be searched for directly, using the predicted signal as a template; our calculations suggest this signal is just beyond what is possible with Planck, with a signal-to-noise rising to unity only for an angular resolution of about 4 arc minutes (\({\ell _\text {max}} =3000\)). In this concluding chapter we also discuss interesting extensions to our work and to our code, SONG, such as: computing the intrinsic power spectrum of the B polarisation; quantifying the effect of modified gravity on the intrinsic bispectrum; studying the generation of magnetic fields due to non-linear effects before and during recombination.
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Beneke M, Fidler C, Klingmüller K (2011) B polarization of cosmic background radiation from second-order scattering sources. J Cosmol Astropart Phys 4:008. doi:10.1088/1475-7516/2011/04/008. arXiv:1102.1524
Fenu E, Pitrou C, Maartens R (2011) The seed magnetic field generated during recombination. MNRAS 414:2354–2366. doi:10.1111/j.1365-2966.2011.18554.x. arXiv:1012.2958
Fidler C, Pettinari GW, Beneke M, Crittenden R, Koyama K, Wands D (2014) The intrinsic B-mode polarisation of the Cosmic Microwave Background. J Cosmol Astropart Phys 7:011. doi:10.1088/1475-7516/2014/07/011. arXiv:1401.3296
Fidler C, Koyama K, Pettinari GW (2015) A new line-of-sight approach to the non-linear Cosmic Microwave Background. J Cosmol Astropart Phys 4:037. doi:10.1088/1475-7516/2015/04/037. arXiv:1409.2461
Gao X (2011) Testing gravity with non-Gaussianity. Phys Lett B 702:197–200. doi:10.1016/j.physletb.2011.07.022. arXiv:1008.2123
Hanson D, Smith KM, Challinor A, Liguori M (2009) CMB lensing and primordial non-Gaussianity. Phys Rev D 80(8):083004. doi:10.1103/PhysRevD.80.083004. arXiv:0905.4732
Hazumi M, Borrill J, Chinone Y, Dobbs MA, et al (2012) LiteBIRD: a small satellite for the study of B-mode polarization and inflation from cosmic background radiation detection. In: Society of Photo-Optical Instrumentation Engineers (SPIE) conference series, vol 8442. doi:10.1117/12.926743
Hu W, Cooray A (2001) Gravitational time delay effects on cosmic microwave background anisotropies. Phys Rev D 63(2):023504. doi:10.1103/PhysRevD.63.023504. arXiv:astro-ph/0008001
Huang Z, Vernizzi F (2013) Cosmic microwave background bispectrum from recombination. Phys Rev Lett 110(101):303. doi:10.1103/PhysRevLett.110.101303. http://link.aps.org/doi/10.1103/PhysRevLett.110.101303
Kamionkowski M, Kosowsky A, Stebbins A (1997) A probe of primordial gravity waves and vorticity. Phys Rev Lett 78:2058–2061. doi:10.1103/PhysRevLett.78.2058. arXiv:astro-ph/9609132
Kogut A, Fixsen DJ, Chuss DT, Dotson J et al (2011) The Primordial Inflation Explorer (PIXIE): a nulling polarimeter for cosmic microwave background observations. J Cosmol Astropart Phys 7:025. doi:10.1088/1475-7516/2011/07/025. arXiv:1105.2044
Lewis A (2012) The full squeezed CMB bispectrum from inflation. J Cosmol Astropart Phys 6:023. doi:10.1088/1475-7516/2012/06/023. arXiv:1204.5018
Lewis A, Challinor A (2006) Weak gravitational lensing of the CMB. Phys Rep 429:1–65. doi:10.1016/j.physrep.2006.03.002. arXiv:astro-ph/0601594
Lewis A, Challinor A, Hanson D (2011) The shape of the CMB lensing bispectrum. J Cosmol Astropart Phys 3:018. doi:10.1088/1475-7516/2011/03/018. arXiv:1101.2234
Matsumura T, Akiba Y, Borrill J, Chinone Y, Dobbs M,Fuke,et al (2014) Mission Design of LiteBIRD. J Low Temp Phys 176:733–740. doi:10.1007/s10909-013-0996-1. arXiv:1311.2847
Mollerach S, Harari D, Matarrese S (2004) CMB polarization from secondary vector and tensor modes. Phys Rev D 69(6):063002. doi:10.1103/PhysRevD.69.063002. arXiv:astro-ph/0310711
Pettinari GW, Fidler C, Crittenden R, Koyama K, Lewis A, Wands D (2014) Impact of polarization on the intrinsic cosmic microwave background bispectrum. Phys Rev D 90:103010. doi:10.1103/PhysRevD.90.103010. http://link.aps.org/doi/10.1103/PhysRevD.90.103010
Pitrou C, Bernardeau F, Uzan JP (2010) The y-sky: diffuse spectral distortions of the cosmic microwave background. J Cosmol Astropart Phys 7:019. doi:10.1088/1475-7516/2010/07/019. arXiv:0912.3655
Pitrou C, Uzan J, Bernardeau F (2010) The cosmic microwave background bispectrum from the non-linear evolution of the cosmological perturbations. J Cosmol Astropart Phys 7:3. doi:10.1088/1475-7516/2010/07/003. arXiv:1003.0481
PRISM Collaboration (2013) The Polarized Radiation Imaging and Spectroscopy Mission. arXiv:1310.1554
PRISM Collaboration (2014) PRISM (Polarized Radiation Imaging and Spectroscopy Mission): an extended white paper. doi:10.1088/1475-7516/2014/02/006. arXiv:1306.2259
Renaux-Petel S, Fidler C, Pitrou C, Pettinari GW (2014) Spectral distortions in the cosmic microwave background polarization. J Cosmol Astropart Phys 3:033. doi:10.1088/1475-7516/2014/03/033. arXiv:1312.4448
Seljak U, Zaldarriaga M (1997) Signature of Gravity Waves in the Polarization of the microwave background. Phys Rev Lett 78:2054–2057. doi:10.1103/PhysRevLett.78.2054. arXiv:astro-ph/9609169
Serra P, Cooray A (2008) Impact of secondary non-Gaussianities on the search for primordial non-Gaussianity with CMB maps. Phys Rev D 77(10):107305. doi:10.1103/PhysRevD.77.107305. arXiv:0801.3276
Smith KM, Zaldarriaga M (2011) Algorithms for bispectra: forecasting, optimal analysis and simulation. MNRAS 417:2–19. doi:10.1111/j.1365-2966.2010.18175.x. arXiv:astro-ph/0612571
Su SC, Lim EA, Shellard EPS (2012) CMB bispectrum from non-linear effects during recombination. arXiv:1212.6968
Sunyaev RA, Zeldovich YB (1970) Small-scale fluctuations of relic radiation. Ap & SS 7:3–19. doi:10.1007/BF00653471
Zaldarriaga M, Seljak U (1998) Gravitational lensing effect on cosmic microwave background polarization. Phys Rev D 58:023003. doi:10.1103/PhysRevD.58.023003. http://link.aps.org/doi/10.1103/PhysRevD.58.023003
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Pettinari, G.W. (2016). Conclusions. In: The Intrinsic Bispectrum of the Cosmic Microwave Background. Springer Theses. Springer, Cham. https://doi.org/10.1007/978-3-319-21882-3_7
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