Planck 2015 results. I. Overview of products and scientific results

TL;DR

Planck 2015 Overview presents a comprehensive, fully calibrated, multi-frequency CMB dataset combining temperature and polarization from the complete 2009–2013 mission. It details improvements in data processing, beam modeling, pointing, and calibration, particularly using the orbital dipole, and delivers extensive simulations, sky maps, and foreground catalogues plus robust CMB and lensing likelihoods. The results reinforce a near-ΛCDM cosmology with tighter parameter constraints, while polarization systematics at large scales remain a challenge for future improvements. The release also provides rich astrophysical foreground maps and source catalogs, enabling precise studies of Galactic and extragalactic phenomena alongside cosmology. Overall, Planck 2015 achieves higher precision and better-understood data, paving the way for refined cosmological and astrophysical inferences in the near term.

Abstract

The European Space Agency's Planck satellite, dedicated to studying the early Universe and its subsequent evolution, was launched 14~May 2009 and scanned the microwave and submillimetre sky continuously between 12~August 2009 and 23~October 2013. In February~2015, ESA and the Planck Collaboration released the second set of cosmology products based on data from the entire Planck mission, including both temperature and polarization, along with a set of scientific and technical papers and a web-based explanatory supplement. This paper gives an overview of the main characteristics of the data and the data products in the release, as well as the associated cosmological and astrophysical science results and papers. The science products include maps of the cosmic microwave background (CMB), the thermal Sunyaev-Zeldovich effect, and diffuse foregrounds in temperature and polarization, catalogues of compact Galactic and extragalactic sources (including separate catalogues of Sunyaev-Zeldovich clusters and Galactic cold clumps), and extensive simulations of signals and noise used in assessing the performance of the analysis methods and assessment of uncertainties. The likelihood code used to assess cosmological models against the Planck data are described, as well as a CMB lensing likelihood. Scientific results include cosmological parameters deriving from CMB power spectra, gravitational lensing, and cluster counts, as well as constraints on inflation, non-Gaussianity, primordial magnetic fields, dark energy, and modified gravity.

Figures (4)

• Figure 1: Noise stationarity for a selection of two bolometers. The left panels show the total noise trends for each bolometer (dots). The solid line shows a running box average. The black dots are from the 2013 data release and the blue dots concern this release. The right panels show a histogram of the trends on the left. The box gives the width of the distribution at half maximum, as measured on the histogram, normalized to the mean noise level. The time response deconvolution has changed between the two data release and hence the absolute noise level is different.
• Figure 2: Fraction of discarded data per bolometer (squares with thick black line). The fraction of data discarded from glitch-flagging alone is shown with stars and the thin green line. The blue line with diamonds indicates the average fraction of discarded samples in valid rings. The two RTS bolometers (143_8 and 545_3) are not shown, since they are not used in the data processing.
• Figure 3: Reconstructed tilt (wobble) angles between the satellite body frame and the principal axis frame. Vertical blue lines mark the ends of operation years and the dashed black line indicates day 540 after launch, when the thermal control on the LFI radiometer electronics box assembly (REBA) was adjusted. Top: First angle, $\psi_1$, corresponds to a rotation about the satellite axis just 5∘$^\circ$ off the focal plane centre. Observed changes in $\psi_1$ only have a small impact on focal plane line-of-sight. Bottom: Second angle, $\psi_2$, is perpendicular to a plane defined by the nominal spin axis and the telescope line of sight. Rotation in $\psi_2$ immediately impacts the opening angle and thus the cross-scan position of the focal plane. We also plot a scaled and translated version of the Solar distance that correlates well with $\psi_2$ until the reconstructed angles became compromised around day 1000 after launch.
• Figure 4: Our ad hoc pointing correction, PTCOR, and a selection of observed planet position offsets after applying the correction. Top: Cross-scan pointing offset. This angle is directly affected by the second tilt angle, $\psi_2$, in Fig. \ref{['fig:wobble_angles']}. Bottom: In-scan pointing offset. This angle corresponds to the spin phase and matches the third satellite tilt angle, $\psi_3$. Since $\psi_3$ is poorly resolved by standard attitude reconstruction, the in-scan pointing was already driven by PTCOR in the 2013 release.