Simultaneous measurement of cosmology and intrinsic alignments using joint cosmic shear and galaxy number density correlations

By B. Joachimi, S. B. K. C. London, Argelander Institut fur Astronomie, U. Bonn. 2009

163 citations recorded by the source corpus.

Aims. Cosmic shear is a powerful method to constrain cosmology, provided that any systematic effects are under control. The intrinsic alignment of galaxies is expected to severely bias parameter estimates if not taken into account. We explore the potential of a joint analysis of tomographic galaxy ellipticity, galaxy number density, and ellipticity-number density cross-correlations to simultaneously constrain cosmology and self-calibrate unknown intrinsic alignment and galaxy bias contributions. Methods. We treat intrinsic alignments and galaxy biasing as free functions of scale and redshift and marginalise over the resulting parameter sets. Constraints on cosmology are calculated by combining the likelihoods from all two-point correlations between galaxy ellipticity and galaxy number density. The information required for these calculations is already available in a standard cosmic shear data set. We include contributions to these functions from cosmic shear, intrinsic alignments, galaxy clustering and magnification effects. Results. In a Fisher matrix analysis we compare our constraints with those from cosmic shear alone in the absence of intrinsic alignments. For a potential future large area survey, such as Euclid, the extra information from the additional correlation functions can make up for the additional free parameters in the intrinsic alignment and galaxy bias terms, depending on the flexibility in the models. For example, the dark energy task force figure of merit is recovered even when more than 100 free parameters are marginalised over. We find that the redshift quality requirements are similar to those calculated in the absence of intrinsic alignments.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b4cd71f677335fb8354556e5c7f50aa2a3219c74

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Citations in the corpus

CFHTLenS tomographic weak lensing cosmological parameter constraints: Mitigating the impact of intrinsic galaxy alignments (2013, methodology): “By selfcalibrating the intrinsic alignment model with the additional information from galaxy clustering (Bernstein 2009; Zhang 2010; Joachimi & Bridle 2010), the marginalisation over many intrinsic alignment nuisance parameters will become feasible.”
The Intrinsic Alignment of Galaxies and its Impact on Weak Gravitational Lensing in an Era of Precision Cosmology (2014, methodology): “A similar process that doesn’t use the separation dependence of the signals was also employed by Joachimi and Bridle (2010); Kirk et al. (2010) as part of simultaneously marginalizing over the presence of both intrinsic alignment and magnification in the observed correlations to constrain…”
Core Cosmology Library: Precision Cosmological Predictions for LSST (2018, background): “13 See the weak lensing review by Bartelmann & Schneider (2001) and Joachimi & Bridle (2010).”
Galaxy Alignments: Observations and Impact on Cosmology (2015, methodology): “Exploitation of some of this set of observables has been proposed in different ways (Zhang 2010; Troxel & Ishak 2012b,a) and has been shown to be an effective self-calibration strategy in forecasts (Bernstein 2009; Joachimi & Bridle 2010; Laszlo et al. 2012; Kirk et al. 2013).”
Constraining primordial non-Gaussianity with future galaxy surveys (2011, methodology): “…only considered weak-lensing data and did not include variations on any other cosmological parameter but fNL; the results by Carbone et al. (2010) only considered the 3D galaxy power spectrum and only the local type of PNG, while Joachimi & Bridle (2010); Wang et al. (2010) did not consider PNG.”
Observational probes of cosmic acceleration (2012, methodology): “Further discussions of this approach and an application to observational data may be found in Bernstein (2009), Joachimi and Bridle (2010), and Kirk et al. (2010).”
Constraints on intrinsic alignment contamination of weak lensing surveys using the MegaZ-LRG sample (2010, methodology): “We note in passing that if the measurements included correlations between galaxies at largely different redshifts to which galaxy-galaxy lensing would be the dominant contribution, it would be possible to simultaneously measure the gG and gI signals, see e.g. Joachimi & Bridle (2010).”
COSMOLIKE - cosmological likelihood analyses for photometric galaxy surveys (2016, methodology): “Similar analyses are presented in Joachimi & Bridle (2010) and Yoo & Seljak (2012), where the latter considers number counts of galaxy clusters instead of cosmic shear.”
KiDS+GAMA : cosmology constraints from a joint analysis of cosmic shear, galaxy-galaxy lensing, and angular clustering (2017, background): “The galaxy-matter power spectrum has a galaxyintrinsic contribution (e.g. Joachimi & Bridle 2010).”
KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering (2017, background): “(9) Here, J2 is the second-order Bessel function of the first kind, and the {gG, gI} power spectra are, respectively, given by (e.g. Hu & Jain 2004; Joachimi & Bridle 2010; Joudaki & Kaplinghat 2012): C j gG( ) = ∫ χH 0 dχ ñ(χ )b(k, χ )qj (χ ) [fK (χ )]2 Pδδ ( + 1/2 fK (χ ) , χ ) , (10) and C j…”
Weak Gravitational Lensing (2012, background): “The parameters of the model can thus be varied and marginalized over to constrain cosmological parameters [13, 10, 39].”
Intrinsic alignments of SDSS-III BOSS LOWZ sample galaxies (2014, background): “…these models observationally is important for all techniques for mitigating intrinsic alignments in future weak lensing surveys that involve marginalizing over models with some free parameters (e.g., Joachimi & Bridle 2010); these techniques require valid models, and priors on the model parameters.”