The lack of power of large-angle CMB anisotropies is known to increase its statistical significance at higher Galactic latitudes, where a string-inspired pre-inflationary scale Δ can also be detected. Considering the Planck 2015 data, and relying largely on a Bayesian approach, we show that the effect is mostly driven by the even -ℓ harmonic multipoles with ℓ≲20, which appear sizably suppressed in a way that is robust with respect to Galactic masking, along with the corresponding detections of Δ. On the other hand, the first odd -ℓ multipoles are only suppressed at high Galactic latitudes. We investigate this behavior in different sky masks, constraining Δ through even and odd multipoles, and we elaborate on possible implications. We include low-ℓ polarization data which, despite being noise-limited, help in attaining confidence levels of about 3 σ in the detection of Δ. We also show by direct forecasts that a future all-sky E-mode cosmic-variance-limited polarization survey may push the constraining power for Δ beyond 5 σ.

The evens and odds of CMB anomalies

Kitazawa, N.
Investigation
;
Natoli, P.
Investigation
;
Sagnotti, A.
Investigation
2018

Abstract

The lack of power of large-angle CMB anisotropies is known to increase its statistical significance at higher Galactic latitudes, where a string-inspired pre-inflationary scale Δ can also be detected. Considering the Planck 2015 data, and relying largely on a Bayesian approach, we show that the effect is mostly driven by the even -ℓ harmonic multipoles with ℓ≲20, which appear sizably suppressed in a way that is robust with respect to Galactic masking, along with the corresponding detections of Δ. On the other hand, the first odd -ℓ multipoles are only suppressed at high Galactic latitudes. We investigate this behavior in different sky masks, constraining Δ through even and odd multipoles, and we elaborate on possible implications. We include low-ℓ polarization data which, despite being noise-limited, help in attaining confidence levels of about 3 σ in the detection of Δ. We also show by direct forecasts that a future all-sky E-mode cosmic-variance-limited polarization survey may push the constraining power for Δ beyond 5 σ.
2018
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
CMB; Inflation; Low-ℓ anomaly; String Theory; Supergravity; Astronomy and Astrophysics; Space and Planetary Science
File in questo prodotto:
File Dimensione Formato  
1712.03288.pdf

accesso aperto

Tipologia: Submitted version (pre-print)
Licenza: Creative Commons
Dimensione 3.76 MB
Formato Adobe PDF
3.76 MB Adobe PDF
1-s2.0-S2212686418300219-main.pdf

Accesso chiuso

Descrizione: Version of Record (publisher's pdf)
Tipologia: Published version
Licenza: Non pubblico
Dimensione 2.7 MB
Formato Adobe PDF
2.7 MB Adobe PDF   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/74544
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 29
  • ???jsp.display-item.citation.isi??? 27
social impact