TY - JOUR
T1 - Hint of a truncated primordial spectrum from the CMB large-scale anomalies
AU - Melia, Fulvio
AU - Ma, Qingbo
AU - Wei, Jun Jie
AU - Yu, Bo
N1 - Funding Information:
Acknowledgements. We are grateful to the anonymous referee for their helpful and thoughtful review of this manuscript. FM is also grateful to Amherst College for its support through a John Woodruff Simpson Lectureship. This work is partially supported by the National Natural Science Foundation of China (grant No. U1831122), the Youth Innovation Promotion Association (2017366), and the Key Research Program of Frontier Sciences (grant No. ZDBS-LY-7014) of Chinese Academy of Sciences, at Purple Mountain Observatory, and by the Innovation and Entrepreneurial Project of Guizhou Province for High-level Overseas Talents (grant No. 2019-02), the National Natural Science Foundation of China (grant No. 11903010), and the Science and Technology Fund of Guizhou Province (grant No. 2020-1Y020), at Guizhou Normal University.
Funding Information:
We are grateful to the anonymous referee for their helpful and thoughtful review of this manuscript. FM is also grateful to Amherst College for its support through a John Woodruff Simpson Lectureship. This work is partially supported by the National Natural Science Foundation of China (grant No. U1831122), the Youth Innovation Promotion Association (2017366), and the Key Research Program of Frontier Sciences (grant No. ZDBS-LY-7014) of Chinese Academy of Sciences, at Purple Mountain Observatory, and by the Innovation and Entrepreneurial Project of Guizhou Province for High-level Overseas Talents (grant No. 2019-02), the National Natural Science Foundation of China (grant No. 11903010), and the Science and Technology Fund of Guizhou Province (grant No. 2020-1Y020), at Guizhou Normal University.
Publisher Copyright:
© 2021 ESO.
PY - 2021/11/1
Y1 - 2021/11/1
N2 - Context. Several satellite missions have uncovered a series of potential anomalies in the fluctuation spectrum of the cosmic microwave background temperature, including: (1) an unexpectedly low level of correlation at large angles, manifested via the angular correlation function, C(θ); and (2) missing power in the low multipole moments of the angular power spectrum, Cℓ. Aims. Their origin is still debated, however, due to a persistent lack of clarity concerning the seeding of quantum fluctuations in the early Universe. A likely explanation for the first of these appears to be a cutoff, kmin = (3.14 ± 0.36) × 10-4 Mpc-1, in the primordial power spectrum, P(k). Our goal in this paper is twofold: (1) we examine whether the same kmin can also self-consistently explain the missing power at large angles, and (2) we confirm that the introduction of this cutoff in P(k) does not adversely affect the remarkable consistency between the prediction of Planck-ΛCDM and the Planck measurements at ℓ > 30. Methods. We have used the publicly available code CAMB to calculate the angular power spectrum, based on a line-of-sight approach. The code was modified slightly to include the additional parameter (i.e., kmin) characterizing the primordial power spectrum. In addition to this cutoff, the code optimized all of the usual standard-model parameters. Results. In fitting the angular power spectrum, we found an optimized cutoff, kmin = (2.04+1.4-0.79) × 10-4 Mpc-1, when using the whole range of ℓ's, and kmin = (3.3+1.7-1.3) × 10-4 Mpc-1, when fitting only the range ℓ ≤ 30, where the Sachs-Wolfe effect is dominant. Conclusions. These are fully consistent with the value inferred from C(θ), suggesting that both of these large-angle anomalies may be due to the same truncation in P(k).
AB - Context. Several satellite missions have uncovered a series of potential anomalies in the fluctuation spectrum of the cosmic microwave background temperature, including: (1) an unexpectedly low level of correlation at large angles, manifested via the angular correlation function, C(θ); and (2) missing power in the low multipole moments of the angular power spectrum, Cℓ. Aims. Their origin is still debated, however, due to a persistent lack of clarity concerning the seeding of quantum fluctuations in the early Universe. A likely explanation for the first of these appears to be a cutoff, kmin = (3.14 ± 0.36) × 10-4 Mpc-1, in the primordial power spectrum, P(k). Our goal in this paper is twofold: (1) we examine whether the same kmin can also self-consistently explain the missing power at large angles, and (2) we confirm that the introduction of this cutoff in P(k) does not adversely affect the remarkable consistency between the prediction of Planck-ΛCDM and the Planck measurements at ℓ > 30. Methods. We have used the publicly available code CAMB to calculate the angular power spectrum, based on a line-of-sight approach. The code was modified slightly to include the additional parameter (i.e., kmin) characterizing the primordial power spectrum. In addition to this cutoff, the code optimized all of the usual standard-model parameters. Results. In fitting the angular power spectrum, we found an optimized cutoff, kmin = (2.04+1.4-0.79) × 10-4 Mpc-1, when using the whole range of ℓ's, and kmin = (3.3+1.7-1.3) × 10-4 Mpc-1, when fitting only the range ℓ ≤ 30, where the Sachs-Wolfe effect is dominant. Conclusions. These are fully consistent with the value inferred from C(θ), suggesting that both of these large-angle anomalies may be due to the same truncation in P(k).
KW - Cosmic background radiation
KW - Cosmological parameters
KW - Cosmology: observations
KW - Cosmology: theory
KW - Large-scale structure of Universe
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U2 - 10.1051/0004-6361/202141251
DO - 10.1051/0004-6361/202141251
M3 - Article
AN - SCOPUS:85120306900
SN - 0004-6361
VL - 655
JO - Astronomy and astrophysics
JF - Astronomy and astrophysics
M1 - A70
ER -