تقرير
Non-Gaussian deflections in iterative optimal CMB lensing reconstruction
| العنوان: | Non-Gaussian deflections in iterative optimal CMB lensing reconstruction |
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| المؤلفون: | Darwish, Omar, Belkner, Sebastian, Legrand, Louis, Carron, Julien, Fabbian, Giulio |
| سنة النشر: | 2024 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Cosmology and Nongalactic Astrophysics |
| الوصف: | The gravitational lensing signal from the Cosmic Microwave Background is highly valuable to constrain the growth of the structures in the Universe in a clean and robust manner over a wide range of redshifts. One of the theoretical systematics for lensing reconstruction is the impact of the lensing field non-Gaussianities on its estimators. Non-linear matter clustering and post-Born lensing corrections are known to bias standard quadratic estimators to some extent, most significantly so in temperature. In this work, we explore the impact of non-Gaussian deflections on Maximum a Posteriori lensing estimators, which, in contrast to quadratic estimators, are able to provide optimal measurements of the lensing field. We show that these naturally reduce the induced non- Gaussian bias and lead to unbiased cosmological constraints in $\Lambda$CDM at CMB-S4 noise levels without the need for explicit modelling. We also test the impact of assuming a non-Gaussian prior for the reconstruction; this mitigates the effect further slightly, but generally has little impact on the quality of the reconstruction. This shows that higher-order statistics of the lensing deflections are not expected to present a major challenge for optimal CMB lensing reconstruction in the foreseeable future. Comment: 18 figures |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2407.00228 |
| رقم الأكسشن: | edsarx.2407.00228 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |