Scale-dependent dipolar modulation and the quadrupole-octopole alignment in the CMB temperature. (arXiv:1909.06093v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Marcos_Caballero_A/0/1/0/all/0/1">A. Marcos-Caballero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martinez_Gonzalez_E/0/1/0/all/0/1">E. Martínez-González</a>
The connection between the dipolar modulation asymmetry and the
quadrupole-octopole alignment in the CMB is studied in this work. First, a
generalization of the dipolar modulation model is proposed by considering that
the amplitude may depend on the scale. As derived from a Bayesian inference
analysis, this model fits the CMB data better than the scale-independent one.
As an extension of the standard model, the scale-dependent dipolar modulation
shows comparable evidence to the standard isotropic model in the large scales
($ell_mathrm{max} leq 64$). The posterior distribution of the parameters of
the scale-dependent model suggests that the amplitude of the dipolar modulation
is large at the lowest multipoles. This large asymmetry induces a detectable
correlation between the quadrupole and the octopole. The significance of the
quadrupole-octopole alignment is analyzed under the assumption that the
Universe has a scale-dependent dipolar modulation. The three alignment
estimators considered in this paper show an increment of $80%$ in the p-value,
showing a clear correlation between these two CMB anomalies. Within this new
scenario, only one of the alignment estimators is still below the $1%$
probability level.
The connection between the dipolar modulation asymmetry and the
quadrupole-octopole alignment in the CMB is studied in this work. First, a
generalization of the dipolar modulation model is proposed by considering that
the amplitude may depend on the scale. As derived from a Bayesian inference
analysis, this model fits the CMB data better than the scale-independent one.
As an extension of the standard model, the scale-dependent dipolar modulation
shows comparable evidence to the standard isotropic model in the large scales
($ell_mathrm{max} leq 64$). The posterior distribution of the parameters of
the scale-dependent model suggests that the amplitude of the dipolar modulation
is large at the lowest multipoles. This large asymmetry induces a detectable
correlation between the quadrupole and the octopole. The significance of the
quadrupole-octopole alignment is analyzed under the assumption that the
Universe has a scale-dependent dipolar modulation. The three alignment
estimators considered in this paper show an increment of $80%$ in the p-value,
showing a clear correlation between these two CMB anomalies. Within this new
scenario, only one of the alignment estimators is still below the $1%$
probability level.
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