Mock galaxy redshift catalogues from simulations: implications for Pan-STARRS1

Cai, Yan-Chuan; Angulo, Raúl E.; Baugh, C. M.; Cole, Shaun; Frenk, Carlos S.; Jenkins, Adrian

doi:10.1111/j.1365-2966.2009.14402.x

Cited by 20 publications

(21 citation statements)

References 81 publications

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“…All three sets contain the nominal NIR photometry expected from Euclid but have different choices for the depth in grizy , and therefore explore the requirements for the ground‐based complement of the IR survey. Survey‐A, which we generally find to be inadequate, uses the point‐source sensitivities from Cai et al (2009). This is therefore a possibly optimistic representation of a PS‐1‐like survey.…”

Section: Generation Of the Photometric Cataloguesmentioning

confidence: 99%

Photo-z performance for precision cosmology

Bordoloi¹,

Lilly²,

Amara³

2010

Monthly Notices of the Royal Astronomical Society

101

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Current and future weak‐lensing surveys will rely on photometrically estimated redshifts of very large numbers of galaxies. In this paper, we address several different aspects of the demanding photo‐z performance that will be required for future experiments, such as the proposed ESA Euclid mission. It is first shown that the proposed all‐sky near‐infrared photometry from Euclid, in combination with anticipated ground‐based photometry (e.g. PanStarrs‐2 or DES) should yield the required precision in individual photo‐z of σz(z) ≤ 0.05(1 +z) at IAB≤ 24.5. Simple a priori rejection schemes based on the photometry alone can be tuned to recognize objects with wildly discrepant photo‐z and to reduce the outlier fraction to ≤0.25 per cent with only modest loss of otherwise usable objects. Turning to the more challenging problem of determining the mean redshift 〈z〉 of a set of galaxies to a precision of |Δ〈z〉| ≤ 0.002(1 +z) we argue that, for many different reasons, this may be best accomplished by relying on the photo‐z themselves rather than on the direct measurement of 〈z〉 from spectroscopic redshifts of a representative subset of the galaxies, as has usually been envisaged. We present in an analysis of the substantial difficulties in the latter approach that arise from the presence of large‐scale structure in spectroscopic survey fields. A simple adaptive scheme based on the statistical properties of the photo‐z likelihood functions is shown to meet this stringent systematic requirement, although further tests on real data will be required to verify this. We also examine the effect of an imprecise correction for Galactic extinction on the photo‐z and the precision with which the Galactic extinction can be determined from the photometric data itself, for galaxies with or without spectroscopic redshifts. We also explore the effects of contamination by fainter overlapping objects in photo‐z determination. The overall conclusion of this paper is that the acquisition of photometrically estimated redshifts with the precision required for Euclid, or other similar experiments, will be challenging but possible.

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Section: Generation Of the Photometric Cataloguesmentioning

confidence: 99%

Photo-z performance for precision cosmology

Bordoloi¹,

Lilly²,

Amara³

2010

Monthly Notices of the Royal Astronomical Society

101

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“…Hence separating galaxies into redshift bins strongly improves the constraining power of cosmic shear on cosmological model parameters (Hu 1999). Extensive studies have been reported in the literature that look for optimal configurations of redshift binning and requirements for future ambitious surveys, covering several thousand square degrees, (Amara & Réfrégier 2007;Banerji et al 2008;Cai et al 2009;Sun et al 2009;Bernstein & Huterer 2010;Abdalla et al 2008;Bellagamba et al 2012;Bordoloi et al 2010Bordoloi et al , 2012Sheldon et al 2012;Cunha et al 2014). In addition to gains in statistical precision, separating galaxies into tomographic bins can also mitigate astrophysical systematics.…”

Section: Introductionmentioning

confidence: 99%

Redshift distributions of galaxies in the Dark Energy Survey Science Verification shear catalogue and implications for weak lensing

Bonnett¹,

Troxel²,

Hartley³

et al. 2016

Phys. Rev. D

147

129

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We present photometric redshift estimates for galaxies used in the weak lensing analysis of the Dark Energy Survey Science Verification (DES SV) data. Four model-or machine learning-based photometric redshift methods -annz2, bpz calibrated against BCC-Ufig simulations, skynet, and tpz -are analysed. For training, calibration, and testing of these methods, we construct a catalogue of spectroscopically confirmed galaxies matched against DES SV data. The performance of the methods is evaluated against the matched spectroscopic catalogue, focusing on metrics relevant for weak lensing analyses, with additional validation against COSMOS photo-zs. From the galaxies in the DES SV shear catalogue, which have mean redshift 0.72 ± 0.01 over the range 0.3 < z < 1.3, we construct three tomographic bins with means of z = {0.45, 0.67, 1.00}. These bins each have systematic uncertainties δz 0.05 in the mean of the fiducial skynet photo-z n(z). We propagate the errors in the redshift distributions through to their impact on cosmological parameters estimated with cosmic shear, and find that they cause shifts in the value of σ 8 of approx. 3%. This shift is within the one sigma statistical errors on σ 8 for the DES SV shear catalog. We further study the potential impact of systematic differences on the critical surface density, Σ crit , finding levels of bias safely less than the statistical power of DES SV data. We recommend a final Gaussian prior for the photo-z bias in the mean of n(z) of width 0.05 for each of the three tomographic bins, and show that this is a sufficient bias model for the corresponding cosmology analysis.

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“…[40] and [32], respectively, while we denote Pan-STARRS as a wide shallow galaxy survey [44]. TABLE II.…”

Section: B Resultsmentioning

confidence: 99%

Detecting black-hole binary clustering via the second-generation gravitational-wave detectors

2016

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The first discovery of the gravitational-wave (GW) event, GW150914, suggests a higher merger rate of black-hole (BH) binaries. If this is true, a number of BH binaries will be observed via the second-generation GW detectors, and the statistical properties of the observed BH binaries can be scrutinized. A naive but important question to ask is whether the spatial distribution of BH binaries faithfully traces the matter inhomogeneities in the Universe or not. Although the BH binaries are thought to be formed inside the galaxies in most of the scenarios, there is no observational evidence to confirm such a hypothesis. Here, we estimate how well the second-generation GW detectors can statistically confirm the BH binaries to be a tracer of the large-scale structure by looking at the auto-and cross-correlation of BH binaries with photometric galaxies and weak-lensing measurements, finding that, with a 3 year observation, the >3σ detection of a nonzero signal is possible if the BH merger rate today is _ n 0 ≳ 100 Gpc −3 yr −1 and the clustering bias of BH binaries is b BH;0 ≳ 1.5.

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Mock galaxy redshift catalogues from simulations: implications for Pan-STARRS1

Cited by 20 publications

References 81 publications

Photo-z performance for precision cosmology

Photo-z performance for precision cosmology

Redshift distributions of galaxies in the Dark Energy Survey Science Verification shear catalogue and implications for weak lensing

Detecting black-hole binary clustering via the second-generation gravitational-wave detectors

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