Planck 2018 results IX. Constraints on primordial non-Gaussianity

Yashar Akrami (1) , F. Arroja , M. Ashdown , J. Aumont , C. Baccigalupi , M. Ballardini , A. J. Banday (2) , R. B. Barreiro , N. Bartolo , S. Basak , K. Benabed (3) , J.-P. Bernard , M. Bersanelli (4) , P. Bielewicz , J. R. Bond (5) , J. Borrill (6) , F. R. Bouchet , M. Bucher (7) , C. Burigana , R. C. Butler , E. Calabrese , J.-F. Cardoso (8) , B. Casaponsa , A. Challinor , H. C. Chiang , L. P. L. Colombo , C. Combet (9) , B. P. Crill , F. Cuttaia , P. de Bernardis (10) , A. de Rosa , G. de Zotti , J. Delabrouille (7) , J.-M. Delouis (3) , E. Di Valentino , J. M. Diego , O. Doré (11) , M. Douspis (12) , A. Ducout , X. Dupac , S. Dusini , G. Efstathiou , F. Elsner (13) , T. A. Ensslin , H. K. Eriksen , Y. Fantaye , J. Fergusson , R. Fernandez-Cobos , F. Finelli , M. Frailis , A. A. Fraisse , E. Franceschi , A. Frolov , S. Galeotta , S. Galli , K. Ganga (7) , R. T. Génova-Santos , M. Gerbino , J. González-Nuevo , K. M. Górski (11) , Steven Gratton , A. Gruppuso , J. E. Gudmundsson , J. Hamann , W. Handley , F. K. Hansen , D. Herranz , E. Hivon (3) , Z. Huang , A. H. Jaffe , W. C. Jones , G. Jung , E. Keihänen , R. Keskitalo , K. Kiiveri , J. Kim , N. Krachmalnicoff , M. Kunz , H. Kurki-Suonio , J.-M. Lamarre (14) , A. Lasenby , M. Lattanzi (15) , C. R. Lawrence , M. Le Jeune (7) , F. Levrier (14, 1) , A. Lewis , M. Liguori , P. B. Lilje , V. Lindholm , M. López-Caniego , Y.-Z. Ma , J. F. Macías-Pérez (9) , G. Maggio , D. Maino , N. Mandolesi , A. Marcos-Caballero , M. Maris , P. G. Martin , E. Martínez-González , S. Matarrese (16) , N. Mauri , J. D. Mcewen , P. D. Meerburg (17) , P. R. Meinhold , A. Melchiorri (18) , A. Mennella , M. Migliaccio , M.-A. Miville-Deschênes (19, 20) , D. Molinari , A. Moneti (3) , L. Montier (2) , G. Morgante , A. Moss , M. Münchmeyer , P. Natoli , F. Oppizzi , L. Pagano (12) , D. Paoletti , B. Partridge , G. Patanchon (7) , F. Perrotta , V. Pettorino (21) , F. Piacentini , G. Polenta , J.-L. Puget (12) , J. P. Rachen , B. Racine (22) , M. Reinecke , M. Remazeilles (23) , A. Renzi , G. Rocha (11) , J. A. Rubiño-Martín , B. Ruiz-Granados , L. Salvati (12) , M. Savelainen , D. Scott (24) , E. P. S. Shellard , M. Shiraishi , C. Sirignano , G. Sirri , K. Smith , L. D. Spencer , L. Stanco , R. Sunyaev , A.-S. Suur-Uski , J. A. Tauber , D. Tavagnacco , M. Tenti , L. Toffolatti , M. Tomasi , T. Trombetti , J. Valiviita , B. van Tent (25) , P. Vielva , Francesca Villa , N. Vittorio , B. D. Wandelt (3) , I. K. Wehus , A. Zacchei , A. Zonca

1 Astrophysique
2 IRAP - Institut de recherche en astrophysique et planétologie
3 IAP - Institut d'Astrophysique de Paris
4 UNIPR - Università degli studi di Parma = University of Parma
5 CITA - Canadian Institute for Theoretical Astrophysics
6 LBNL - Lawrence Berkeley National Laboratory [Berkeley]
7 APC (UMR_7164) - AstroParticule et Cosmologie
8 Universidade Aberta [Lisboa]
9 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
10 Dipartimento di Fisica [Roma La Sapienza]
11 JPL - Jet Propulsion Laboratory
12 IAS - Institut d'astrophysique spatiale
13 IAP - Institut d'Astrophysique de Paris
14 LERMA (UMR_8112) - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
15 ICRA and Physics Department
16 Dipartimento di Fisica "G. Galilei"
17 CAM - University of Cambridge [UK]
18 UNIROMA - Università degli Studi di Roma "La Sapienza" = Sapienza University [Rome]
19 IAS - Institut d'astrophysique spatiale
20 AIM (UMR_7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
21 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
22 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
23 University of Manchester [Manchester]
24 UBC - University of British Columbia
25 IJCLab - Laboratoire de Physique des 2 Infinis Irène Joliot-Curie

We analyse the Planck full-mission cosmic microwave background (CMB) temperature and E-mode polarization maps to obtain constraints on primordial non-Gaussianity (NG). We compare estimates obtained from separable template-fitting, binned, and optimal modal bispectrum estimators, finding consistent values for the local, equilateral, and orthogonal bispectrum amplitudes. Our combined temperature and polarization analysis produces the following final results: $f_{NL}^{local}$ = −0.9 ± 5.1; $f_{NL}^{equil}$ = −26 ± 47; and $f_{NL}^{ortho}$ = −38 ± 24 (68% CL, statistical). These results include low-multipole (4 ≤ ℓ <  40) polarization data that are not included in our previous analysis. The results also pass an extensive battery of tests (with additional tests regarding foreground residuals compared to 2015), and they are stable with respect to our 2015 measurements (with small fluctuations, at the level of a fraction of a standard deviation, which is consistent with changes in data processing). Polarization-only bispectra display a significant improvement in robustness; they can now be used independently to set primordial NG constraints with a sensitivity comparable to WMAP temperature-based results and they give excellent agreement. In addition to the analysis of the standard local, equilateral, and orthogonal bispectrum shapes, we consider a large number of additional cases, such as scale-dependent feature and resonance bispectra, isocurvature primordial NG, and parity-breaking models, where we also place tight constraints but do not detect any signal. The non-primordial lensing bispectrum is, however, detected with an improved significance compared to 2015, excluding the null hypothesis at 3.5σ. Beyond estimates of individual shape amplitudes, we also present model-independent reconstructions and analyses of the Planck CMB bispectrum. Our final constraint on the local primordial trispectrum shape is $g_{NL}^{local}$ = (−5.8 ± 6.5) × 10$^4$ (68% CL, statistical), while constraints for other trispectrum shapes are also determined. Exploiting the tight limits on various bispectrum and trispectrum shapes, we constrain the parameter space of different early-Universe scenarios that generate primordial NG, including general single-field models of inflation, multi-field models (e.g. curvaton models), models of inflation with axion fields producing parity-violation bispectra in the tensor sector, and inflationary models involving vector-like fields with directionally-dependent bispectra. Our results provide a high-precision test for structure-formation scenarios, showing complete agreement with the basic picture of the ΛCDM cosmology regarding the statistics of the initial conditions, with cosmic structures arising from adiabatic, passive, Gaussian, and primordial seed perturbations.

Mots clés: cosmic background radiation; cosmology: observations; cosmology: theory; early Universe; inflation; methods: data analysis

Domaines: Astrophysique [astro-ph]

Yashar Akrami, F. Arroja, M. Ashdown, J. Aumont, C. Baccigalupi, et al.. Planck 2018 results IX. Constraints on primordial non-Gaussianity. Astronomy and Astrophysics - A&A, 2020, 641, pp.A9. ⟨10.1051/0004-6361/201935891⟩. ⟨cea-02936948⟩