Research Articles (Earth Sciences)

Permanent URI for this collection

https://hdl.handle.net/10566/273

Browse

Browsing by Author "Aghanim, Nabila"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Planck 2018 results: I. Overview and the cosmological legacy of Planck
    (EDP Sciences, 2020) Aghanim, Nabila; Akrami, Yashar; Arroja, Frederico
    The European Space Agency’s Planck satellite, which was dedicated to studying the early Universe and its subsequent evolution, was launched on 14 May 2009. It scanned the microwave and submillimetre sky continuously between 12 August 2009 and 23 October 2013, producing deep, high-resolution, all-sky maps in nine frequency bands from 30 to 857 GHz. This paper presents the cosmological legacy of Planck, which currently provides our strongest constraints on the parameters of the standard cosmological model and some of the tightest limits available on deviations from that model.
  • Thumbnail Image
    Item
    Planck 2018 results: V. CMB power spectra and likelihoods
    (EDP Sciences, 2020) Aghanim, Nabila; Akrami, Yashar; Ashdown, Mark A.J.
    We describe the legacy Planck cosmic microwave background (CMB) likelihoods derived from the 2018 data release. The overall approach is similar in spirit to the one retained for the 2013 and 2015 data release, with a hybrid method using different approximations at low (ℓ <  30) and high (ℓ ≥ 30) multipoles, implementing several methodological and data-analysis refinements compared to previous releases. With more realistic simulations, and better correction and modelling of systematic effects, we can now make full use of the CMB polarization observed in the High Frequency Instrument (HFI) channels.
  • Thumbnail Image
    Item
    Planck 2018 results: VI. Cosmological parameters
    (EDP Sciences, 2020) Aghanim, Nabila; Akrami, Yashar; Ashdown, Mark A.J.
    We present cosmological parameter results from the final full-mission Planck measurements of the cosmic microwave background (CMB) anisotropies, combining information from the temperature and polarization maps and the lensing reconstruction. Compared to the 2015 results, improved measurements of large-scale polarization allow the reionization optical depth to be measured with higher precision, leading to significant gains in the precision of other correlated parameters. Improved modelling of the small-scale polarization leads to more robust constraints on many parameters, with residual modelling uncertainties estimated to affect them only at the 0.5σ level.
  • Thumbnail Image
    Item
    Planck 2018 results: VIII. Gravitational lensing
    (EDP Sciences, 2020) Aghanim, Nabila; Akrami, Yashar; Ashdown, Mark A.J.
    We present measurements of the cosmic microwave background (CMB) lensing potential using the final Planck 2018 temperature and polarization data. Using polarization maps filtered to account for the noise anisotropy, we increase the significance of the detection of lensing in the polarization maps from 5σ to 9σ. Combined with temperature, lensing is detected at 40σ. We present an extensive set of tests of the robustness of the lensingpotential power spectrum, and construct a minimum-variance estimator likelihood over lensing multipoles 8 ≤ L ≤ 400 (extending the range to lower L compared to 2015), which we use to constrain cosmological parameters. We find good consistency between lensing constraints and the results from the Planck CMB power spectra within the ΛCDM model
  • Thumbnail Image
    Item
    Planck 2018 results: XII. Galactic astrophysics using polarized dust emission
    (EDP Sciences, 2020) Aghanim, Nabila; Akrami, Yashar; Alves, Marta I.R.
    Observations of the submillimetre emission from Galactic dust, in both total intensity I and polarization, have received tremendous interest thanks to the Planck full-sky maps. In this paper we make use of such full-sky maps of dust polarized emission produced from the third public release of Planck data. As the basis for expanding on astrophysical studies of the polarized thermal emission from Galactic dust, we present full-sky maps of the dust polarization fraction p, polarization angle ψ, and dispersion function of polarization angles 𝒮. The joint distribution (one-point statistics) of p and NH confirms that the mean and maximum polarization fractions decrease with increasing NH.