Constraints on intrinsic alignment contamination of weak lensing surveys using the MegaZ-LRG sample

By B. Joachimi, Rachel Mandelbaum, Filipe B. Abdalla, S. Aifa, U. Bonn, U. London, P. University.. 2010

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Correlations between the intrinsic shapes of galaxies and the large-scale galaxy density field provide an important tool to investigate galaxy intrinsic alignments, which constitute the major potential astrophysical systematic in cosmological weak lensing (cosmic shear) surveys, but also yield insight into the formation and evolution of galaxies. We measure galaxy position-shape correlations in the MegaZ-LRG sample for more than 800 000 luminous red galaxies for comoving transverse separations of 0.3 6 h(-1) Mpc, the fits to galaxy position-shape correlation functions are consistent with the scaling with rp and redshift of a revised, nonlinear version of the linear alignment model (Hirata & Seljak 2004) for all samples. An extra redshift dependence. (1 + z)(eta other) is constrained to.other = -0.3 +/- 0.8 (1 sigma). To obtain consistent amplitudes for all data, an additional dependence on galaxy luminosity alpha L-beta with beta = 1.1(-0.2)(+0.3) is required. The normalisation of the intrinsic alignment power spectrum is found to be (0.077 +/- 0.008)rho(-1)(cr) for galaxies at redshift 0.3 and r band magnitude of -22 (k- and evolution-corrected to z = 0).Assuming zero intrinsic alignments for blue galaxies, we assess the bias on cosmological parameters for a tomographic CFHTLSlike lensing survey given our new constraints on the intrinsic alignment model parameter space. Both the resulting mean bias and its uncertainty are smaller than the 1 sigma statistical errors when using the constraints from all samples combined. The addition of MegaZ- LRG data is critical to achieving constraints this strong, reducing the uncertainty in intrinsic alignment bias on cosmological parameters by factors of three to seven.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/6f51ae872580df83cf2987624217f4f0f69c8ba0

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Citations in the corpus

Spin alignments within the cosmic web: a theory of constrained tidal torques near filaments (2015, background): “…2002; Lee & Pen 2002; Bernstein & Norberg 2002; Heymans et al. 2004; Hirata et al. 2004; Hirata & Seljak 2004; Mandelbaum et al. 2006; Hirata et al. 2007; Mandelbaum et al. 2011; Joachimi et al. 2011, 2013a) efforts have been invested to control the level of in- © 0000 The Authors ar X iv :1 50 4.”
CFHTLenS: testing the laws of gravity with tomographic weak lensing and redshift-space distortions (2012, methodology): “The choice to use only two broad high redshift bins in this tomographic analysis was motivated by the desire to mitigate the impact of intrinsic galaxy alignments on the tomographic measurements (see for example Heymans et al. 2006; Joachimi et al. 2011, and references therein).”
KiDS+GAMA : cosmology constraints from a joint analysis of cosmic shear, galaxy-galaxy lensing, and angular clustering (2017, background): “…on results from previous dedicated intrinsic alignment studies; although intrinsic alignments have been detected for luminous red galaxies (e.g. Joachimi et al. 2011; Singh, Mandelbaum & More 2015), the constraints for less luminous red galaxies and blue galaxies are consistent with zero…”
Observational probes of cosmic acceleration (2012, methodology): “Detailed assessments of the intrinsic alignment contamination have been made on the basis of SDSS, 2SLAQ, and WiggleZ observations of wge(rp) (Hirata et al., 2007; Mandelbaum et al., 2011; Joachimi et al., 2011).”
KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering (2017, background): “…constant C1 = 5 × 10−14 h−2M−1 Mpc3, ρcr is the present critical density, D(χ ) is the linear growth factor normalized to unity at present, z0 = 0.3 is the arbitrary pivot redshift and the pivot luminosity L0 corresponds to an absolute r-band magnitude of −22 (e.g. Joachimi et al. 2011).”
Galaxy Alignments: An Overview (2015, methodology): “Contour lines encompass the regions in which 99% of the possible biases on these parameters are located when we sample from the 1σ credible region (thick lines) and the 2σ credible region (thin lines) of the three parameters in the intrinsic alignment model constrained in Joachimi et al. (2011). The”
KiDS-450: testing extensions to the standard cosmological model (2016, methodology): “A weakness of this extension is that it is purely empirical, but it has been fit to data and demonstrated to work well (e.g. Joachimi et al. 2011).”
Masses of Galaxy Clusters from Gravitational Lensing (2013, background): “Under the assumption that the original position angles of the galaxies are distributed randomly (see, however, e.g., Hirata & Seljak 2004; Mandelbaum et al. 2006; Schneider & Bridle 2010; Joachimi et al. 2011), the lensing shear can be inferred by averaging over an ensemble of sources.”
CFHTLenS tomographic weak lensing cosmological parameter constraints: Mitigating the impact of intrinsic galaxy alignments (2013, methodology): “Our early-type sample is most similar in terms of luminosity and redshift to the MegaZLRG sample analysed in Joachimi et al. (2011).”
KiDS-450: cosmological parameter constraints from tomographic weak gravitational lensing (2016, methodology): “We adopt the ‘non-linear–linear’ intrinsic alignment model developed by Hirata & Seljak (2004), Bridle & King (2007), and Joachimi et al. (2011).”
KiDS+VIKING-450 and DES-Y1 combined: Cosmology with cosmic shear (2019, result): “We use a pivot redshift of z0 = 0.3, in agreement with past KiDS analyses and direct measurements of the IA (e.g. Mandelbaum et al. 2011; Joachimi et al. 2011).”
KiDS-450: The tomographic weak lensing power spectrum and constraints on cosmological parameters (2017, unknown): “…in Hildebrandt et al. (2017) and employ the non-linear modification of the tidal alignment model of IAs (Hirata & Seljak 2004; Bridle & King 2007; Joachimi et al. 2011), so that we can write CIIμν( ) = ∫ χH 0 dχ nμ(χ )nν(χ )F 2(χ ) f 2K(χ ) Pδ ( k = + 0.5 fK(χ ) ; χ ) , (21) CGIμν( ) = ∫ χH 0 dχ…”
CFHTLenS: combined probe cosmological model comparison using 2D weak gravitational lensing (2012, background): “…the cosmological shear–shear correlation with an expected bias for σ 8 which is well within the statistical uncertainty (Kirk, Bridle & Schneider 2010; Joachimi et al. 2011; Mandelbaum et al. 2011), see also a joint lensing and IA tomography analysis over the full available redshift range (Heymans…”
Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data (2018, result): “The index for the luminosity dependence of the IA signal for red galaxies has been measured to be β = 1.13+0.25−0.20 for the MegaZ-LRG+SDSS LRG (Joachimi et al. 2011) and β = 1.30± 0.27 for the SDSS LOWZ samples (Singh et al. 2015).”