Jodrell Bank Centre for Astrophysics

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Mathieu Remazeilles

Research Fellow

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I am a Research Fellow in cosmology at the Jodrell Bank Centre for Astrophysics at the University of Manchester.

Previously, I held postdoctoral Research Associate positions at the University of Manchester (2013-2020), the IAS in Orsay (2011-2013), and the APC in Paris (2009-2011), and worked as a Planck Scientist for the ESA's Planck space mission since 2011. I obtained my PhD in Theoretical Physics in 2009 from the University of Paris 11 at the LPT in Orsay, under the supervision of Martin A. Bucher.

My research revolves around the extraction and interpretation of new cosmological observables and information that can be gleaned from submillimetre and radio observations of the early Universe, primarily out of Cosmic Microwave Background (CMB) data: Component separation, primordial CMB B-modes, Sunyaev-Zeldovich effects, CMB spectral distortions, CMB lensing, 21-cm intensity mapping, Planck data analysis (also here and here), extra-dimensions and cosmological perturbations.

    Publication highlights:

  • A new semi-blind component separation method using moment expansion to deal with foreground spectral distortions due to line-of-sight integration and beam convolution

      By combining statistical moment expansion of the foreground emission and constrained ILC method, we have devised a new map-based semi-blind component separation method, called cMILC ("Constrained Moment ILC"), to deal with foreground spectral distortions beyond the leading-order SED which arise from the integration of multiple spectral contributions along the line-of-sight and across the angular beam. At the intersection of blind and parametric methods, the cMILC method allows to deproject the main moments of the foregrounds due to line-of-sight integration and beam convolution, and helps reducing quite significantly the residual foreground contamination in the recovery of primordial CMB B-modes.

      Remazeilles, Rotti, Chluba, "Peeling off foregrounds with the constrained moment ILC method to unveil primordial CMB B modes", MNRAS (2021)

  • ESA Voyage 2050 White Paper: A space mission to map the entire observable universe using the CMB as a backlight

      We just submitted the Science White Paper "CMB Backlight" in response to the ESA Voyage 2050 call for long-term missions planning, in which we describe the various science possibilities that can be realized in cosmology in the next decades with an L-class space observatory that is dedicated to the study of the interactions of the CMB photons with the cosmic web. Our aim is to use the CMB as a "backlight" to probe the total mass, gas, and stellar content across the entire observable Universe, by means of analyzing the spatial and spectral distortions imprinted on the CMB.

      Basu, Remazeilles, Melin, et al, "A Space Mission to Map the Entire Observable Universe using the CMB as a Backlight", arXiv:1909.01592 (2019)

  • Mapping the relativistic electron gas temperature across the sky

      We have developed a new map-based method that allows mapping the relativistic electron gas temperature of galaxy clusters across the entire sky with the relativistic SZ effect, and the diffuse electron gas temperature across a broad range of angular scales. The electron-temperature power spectrum provides a novel independent map-based observable that will complement the usual Compton-y observable to constrain cosmological parameters and break parameter degeneracies with future cosmological analyses of galaxy clusters. The recovered temperatures of a large sample of clusters will offer a new way for determining cluster masses using the relativistic SZ effect. The recovered SZ temperature profile of individual clusters will allow to break the degeneracy between electron density and temperature in the cluster pressure profile, and as a consequence the degeneracy between electron density and velocity profiles in the kinetic SZ effect.

      Remazeilles and Chluba, "Mapping the relativistic electron gas temperature across the sky", MNRAS (2020)

  • Impact on σ8 of relativistic temperature corrections in cosmological SZ analyses of galaxy clusters

  • Unveiling anisotropic μ-type spectral distortions

  • Exploring Cosmic Origins with CORE: B-mode Component Separation

  • Disentangling Galactic dust emission and CIB anisotropies in Planck all-sky observations

  • Forecasts on the tensor-to-scalar ratio for future CMB B-mode polarization satellites

  • The Planck Sunyaev-Zeldovich all-sky map

  • The Reprocessed Haslam 408 MHz all-sky map