Dark energy and cosmic microwave background bispectrum

Verde, Licia; Spergel, David N.

doi:10.1103/physrevd.65.043007

Cited by 64 publications

(118 citation statements)

References 23 publications

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“…The signal of most interest for parameter studies is the linear late ISW since it can be used as a constraint on dark energy models [32] -the CMB lensing potential happens to correlate at the 90% level with the ISW [33]. However the total temperature correlation drops off rapidly with scale as the ISW component of the signal tends to cancel between multiple perturbations along the line of sight.…”

Section: Temperature-lensing Correlationmentioning

confidence: 99%

“…The thermal SZ signal is frequency dependent, but depending on frequency potentially important at l ∼ 100 [34]; I shall not consider this signal further here since it is zero at the SZ null and in principle is isolable by its frequency dependence, as are other potentially significant foreground signals like the correlation with the cosmic infrared background (CIB) [35,36] (the CIB signal is also small at frequencies usually used for cosmological analysis). The late-time ISW effect can also be calculated accurately on intermediate and small scales using the Limber approximation result [32] …”

Section: Temperature-lensing Correlationmentioning

confidence: 99%

“…The importance of Rees-Sciama is significantly smaller than claimed in Refs. [32,39,40] and is always a small correction that is safe to ignore in the region where the signal is well understood 6 .…”

Section: Temperature-lensing Correlationmentioning

confidence: 99%

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The full squeezed CMB bispectrum from inflation

Lewis

2012

J. Cosmol. Astropart. Phys.

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The small-scale CMB temperature we observe on the sky is modulated by perturbations that were super-horizon at recombination, giving differential focussing and lensing that generate a non-zero bispectrum even for single-field inflation where local physics is identical. Understanding this signal is important for primordial non-Gaussianity studies and also parameter constraints from the CMB lensing bispectrum signal. Because of cancellations individual effects can appear larger or smaller than they are in total, so a full analysis may be required to avoid biases. I relate angular scales on the sky to physical scales at recombination using the optical equations, and give full-sky results for the large-scale adiabatic temperature bispectrum from Ricci focussing (expansion of the ray bundle), Weyl lensing (convergence and shear), and temperature redshift modulations of small-scale power. The δN expansion of the beam is described by the constant temperature 3-curvature, and gives a nearly-observable version of the consistency relation prediction from single-field inflation. I give approximate arguments to quantify the likely importance of dynamical effects, and argue that they can be neglected for modulation scales l 100, which is sufficient for lensing studies and also allows robust tests of local primordial non-Gaussianity using only the large-scale modulation modes. For accurate numerical results early and late-time ISW effects must be accounted for, though I confirm that the late-time non-linear Rees-Sciama contribution is negligible compared to other more important complications. The total corresponds to fNL ∼ 7 for Planck-like temperature constraints and fNL ∼ 11 for cosmic-variance limited data to lmax = 2000. Temperature lensing bispectrum estimates are affected at the 0.2σ level by Ricci focussing, and up to 0.5σ with polarization.

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Section: Temperature-lensing Correlationmentioning

confidence: 99%

Section: Temperature-lensing Correlationmentioning

confidence: 99%

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The full squeezed CMB bispectrum from inflation

Lewis

2012

J. Cosmol. Astropart. Phys.

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“…They produce a negligible correlation between lensing amplitude estimates for the multipole ranges considered here. The T −φ correlation is potentially a powerful probe of dark energy dynamics (e.g., Verde & Spergel 2002) and modified theories of gravity (e.g., Acquaviva et al 2004). The power spectrum C T φ can be measured from the Planck data using the CMB 3-point function (Planck Collaboration XXIV 2014) or, equivalently, by cross-correlating the φ reconstruction with the large-angle temperature anisotropies (Planck Collaboration XIX 2014) although the detection significance is only around 3σ.…”

Section: Cmb Lensing Measured By Planckmentioning

confidence: 99%

Planck2013 results. XVI. Cosmological parameters

Ade¹,

Aghanim²,

Armitage-Caplan³

et al. 2014

A&A

5,091

163

2,253

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This paper presents the first cosmological results based on Planck measurements of the cosmic microwave background (CMB) temperature and lensing-potential power spectra. We find that the Planck spectra at high multipoles ( > ∼ 40) are extremely well described by the standard spatiallyflat six-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations. Within the context of this cosmology, the Planck data determine the cosmological parameters to high precision: the angular size of the sound horizon at recombination, the physical densities of baryons and cold dark matter, and the scalar spectral index are estimated to be θ * = (1.04147 ± 0.00062) × 10 −2 , Ω b h 2 = 0.02205 ± 0.00028, Ω c h 2 = 0.1199 ± 0.0027, and n s = 0.9603 ± 0.0073, respectively (note that in this abstract we quote 68% errors on measured parameters and 95% upper limits on other parameters). For this cosmology, we find a low value of the Hubble constant, H 0 = (67.3 ± 1.2) km s −1 Mpc −1 , and a high value of the matter density parameter, Ω m = 0.315 ± 0.017. These values are in tension with recent direct measurements of H 0 and the magnituderedshift relation for Type Ia supernovae, but are in excellent agreement with geometrical constraints from baryon acoustic oscillation (BAO) surveys. Including curvature, we find that the Universe is consistent with spatial flatness to percent level precision using Planck CMB data alone. We use high-resolution CMB data together with Planck to provide greater control on extragalactic foreground components in an investigation of extensions to the six-parameter ΛCDM model. We present selected results from a large grid of cosmological models, using a range of additional astrophysical data sets in addition to Planck and high-resolution CMB data. None of these models are favoured over the standard six-parameter ΛCDM cosmology. The deviation of the scalar spectral index from unity is insensitive to the addition of tensor modes and to changes in the matter content of the Universe. We find an upper limit of r 0.002 < 0.11 on the tensor-to-scalar ratio. There is no evidence for additional neutrino-like relativistic particles beyond the three families of neutrinos in the standard model. Using BAO and CMB data, we find N eff = 3.30 ± 0.27 for the effective number of relativistic degrees of freedom, and an upper limit of 0.23 eV for the sum of neutrino masses. Our results are in excellent agreement with big bang nucleosynthesis and the standard value of N eff = 3.046. We find no evidence for dynamical dark energy; using BAO and CMB data, the dark energy equation of state parameter is constrained to be w = −1.13 +0.13 −0.10 . We also use the Planck data to set limits on a possible variation of the fine-structure constant, dark matter annihilation and primordial magnetic fields. Despite the success of the six-parameter ΛCDM model in describing the Planck data at high multipoles, we note that this cosmology does not provide a good fit to the temperature power spectrum at low multipoles. T...

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“…With the single-lens parameters fixed to the best-fit values, we used the initial condition grid search method to search over the parameter ranges   s 0.48 2.10,   --q 4 log 2, and   p q p -, with t * fixed at * = t 0.05. We then select ∼10 of the best-fit values from the initial condition grid search (with very different values of q s , , and θ) to use as initial conditions for full, nonlinear modeling runs using the Bennett (2010) c 2 minimization recipe, which is a modification of the Markov Chain Monte Carlo algorithm (Verde et al 2003). The parameters of the best-fit binary-lens model and the c 2 improvement are compared with the best-fit single-lens model in Table 2.…”

Section: Best-fit Modelmentioning

confidence: 99%

Discovery of a Gas Giant Planet in Microlensing Event Ogle-2014-BLG-1760

Bhattacharya

Bennett

Bond

et al. 2016

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We present the analysis of the planetary microlensing event OGLE-2014-BLG-1760, which shows a strong lightcurve signal due to the presence of a Jupiter mass ratio planet. One unusual feature of this event is that the source star is quite blue, with -=  V I 1.48 0.08. This is marginally consistent with a source star in the Galactic bulge, but it could possibly indicate a young source star on the far side of the disk. Assuming a bulge source, we perform a Bayesian analysis assuming a standard Galactic model, and this indicates that the planetary system resides in or near the Galactic bulge at =  D 6.9 1.1 kpc , and a projected star-planet separation of = -+ a 1.75 0.33 0.34 au. The lens-source relative proper motion is m =  6.5 1.1 rel mas yr −1 . The lens (and stellar host star) is estimated to be very faint compared to the source star, so it is most likely that it can be detected only when the lens and source stars start to separate. Due to the relatively high relative proper motion, the lens and source will be resolved to about ∼46 mas in 6-8 yr after the peak magnification. So, by 2020-2022, we can hope to detect the lens star with deep, high-resolution images.

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Dark energy and cosmic microwave background bispectrum

Cited by 64 publications

References 23 publications

The full squeezed CMB bispectrum from inflation

The full squeezed CMB bispectrum from inflation

Planck2013 results. XVI. Cosmological parameters

Discovery of a Gas Giant Planet in Microlensing Event Ogle-2014-BLG-1760

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