Dark energy constraints from cosmic shear power spectra: impact of intrinsic alignments on photometric redshift requirements

Bridle, Sarah; King, Lindsay J.

doi:10.1088/1367-2630/9/12/444

Cited by 481 publications

(689 citation statements)

References 48 publications

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“…These errors, and the steps to remove them, are not independent -for example, marginalizing out the intrinsic alignment effects can amplify systematic errors in photometric redshifts (Bridle and King, 2007). The development of systematic error budgets and requirements for future surveys thus requires a global analysis of all of the statistical and systematic uncertainties and their possible degeneracies (Bernstein, 2009).…”

Section: Systematic Errors and Their Amelioration: Summarymentioning

confidence: 99%

Observational probes of cosmic acceleration

et al. 2013

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The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of gravity breaks down on cosmological scales. The profound implications of cosmic acceleration have inspired ambitious efforts to understand its origin, with experiments that aim to measure the history of expansion and growth of structure with percent-level precision or higher. We review in detail the four most well established methods for making such measurements: Type Ia supernovae, baryon acoustic oscillations (BAO), weak gravitational lensing, and the abundance of galaxy clusters. We pay particular attention to the systematic uncertainties in these techniques and to strategies for controlling them at the level needed to exploit "Stage IV" dark energy facilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly review a number of other approaches including redshift-space distortions, the Alcock-Paczynski effect, and direct measurements of the Hubble constant H 0 . We present extensive forecasts for constraints on the dark energy equation of state and parameterized deviations from General Relativity, achievable with Stage III and Stage IV experimental programs that incorporate supernovae, BAO, weak lensing, and cosmic microwave background data. We also show the level of precision required for clusters or other methods to provide constraints competitive with those of these fiducial programs. We emphasize the value of a balanced program that employs several of the most powerful methods in combination, both to cross-check systematic uncertainties and to take advantage of complementary information. Surveys to probe cosmic acceleration produce data sets that support a wide range of scientific investigations, and they continue the longstanding astronomical tradition of mapping the universe in ever greater detail over ever larger scales.

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Section: Systematic Errors and Their Amelioration: Summarymentioning

confidence: 99%

Observational probes of cosmic acceleration

et al. 2013

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“…We follow HE13 by using the non-linear linear alignment model (henceforth NLA model, Bridle & King (2007)) to account for intrinsic alignments. The NLA model is based on the linear alignment model (Catelan et al 2001;Hirata & Seljak 2004), which assumes that galaxies are aligned with their haloes which are in turn are aligned with the local tidal gravitational field; for a given redshift the intrinsic galaxy ellipticity is taken to be proportional to the linear theory tidal field strength.…”

Section: Sensitivity To the Ia Modelmentioning

confidence: 99%

Cosmic discordance: are Planck CMB and CFHTLenS weak lensing measurements out of tune?

MacCrann

Zuntz

Bridle

et al. 2015

Monthly Notices of the Royal Astronomical Society

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177

192

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We examine the level of agreement between low redshift weak lensing data and the CMB using measurements from the CFHTLenS and Planck+WMAP polarization. We perform an independent analysis of the CFHTLenS six bin tomography results of Heymans et al. (2013). We extend their systematics treatment and find the cosmological constraints to be relatively robust to the choice of non-linear modeling, extension to the intrinsic alignment model and inclusion of baryons. We find that when marginalised in the Ω m -σ 8 plane, the 95% confidence contours of CFHTLenS and Planck+WP only just touch, but the discrepancy is less significant in the full 6-dimensional parameter space of ΛCDM. Allowing a massive active neutrino or tensor modes does not significantly resolve the tension in the full n-dimensional parameter space. Our results differ from some in the literature because we use the full tomographic information in the weak lensing data and marginalize over systematics. We note that adding a sterile neutrino to ΛCDM brings the 2d marginalised contours into greater overlap, mainly due to the extra effective number of neutrino species, which we find to be 0.88 ± 0.43 (68%) greater than standard on combining the datasets. We discuss why this is not a completely satisfactory resolution, leaving open the possibility of other new physics or observational systematics as contributing factors. We provide updated cosmology fitting functions for the CFHTLenS constraints and discuss the differences from ones used in the literature.

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“…D(z) is the linear growth factor, normalized to unity at z = 0. Bridle & King (2007b) suggested using the full nonlinear matter power spectrum P nl δ in Eq. (14) to extend the linear alignment model to quasi-linear scales.…”

Section: Formalism: Linear Alignment Modelmentioning

confidence: 99%

Intrinsic alignments of galaxies in the MassiveBlack-II simulation: analysis of two-point statistics

Tenneti

Singh

Mandelbaum

et al. 2015

Monthly Notices of the Royal Astronomical Society

131

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The intrinsic alignment of galaxies with the large-scale density field is an important astrophysical contaminant in upcoming weak lensing surveys. We present detailed measurements of the galaxy intrinsic alignments and associated ellipticity-direction (ED) and projected shape (w g+ ) correlation functions for galaxies in the cosmological hydrodynamic MassiveBlack-II (MB-II) simulation. We carefully assess the effects on galaxy shapes, misalignment of the stellar component with the dark matter shape and two-point statistics of iterative weighted (by mass and luminosity) definitions of the (reduced and unreduced) inertia tensor. We find that iterative procedures must be adopted for a reliable measurement of the reduced tensor but that luminosity versus mass weighting has only negligible effects. Both ED and w g+ correlations increase in amplitude with subhalo mass (in the range of 10 10 − 6.0 × 10 14 h −1 M ), with a weak redshift dependence (from z = 1 to z = 0.06) at fixed mass. At z ∼ 0.3, we predict a w g+ that is in reasonable agreement with SDSS LRG measurements and that decreases in amplitude by a factor of ∼ 5-18 for galaxies in the LSST survey. We also compared the intrinsic alignments of centrals and satellites, with clear detection of satellite radial alignments within their host halos. Finally, we show that w g+ (using subhalos as tracers of density) and w δ+ (using dark matter density) predictions from the simulations agree with that of non-linear alignment models (NLA) at scales where the 2-halo term dominates in the correlations (and tabulate associated NLA fitting parameters). The 1-halo term induces a scale dependent bias at small scales which is not modeled in the NLA model.

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Dark energy constraints from cosmic shear power spectra: impact of intrinsic alignments on photometric redshift requirements

Cited by 481 publications

References 48 publications

Observational probes of cosmic acceleration

Observational probes of cosmic acceleration

Cosmic discordance: are Planck CMB and CFHTLenS weak lensing measurements out of tune?

Intrinsic alignments of galaxies in the MassiveBlack-II simulation: analysis of two-point statistics

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