Apples to apples A<sup>2</sup>– I. Realistic galaxy simulated catalogues and photometric redshift predictions for next-generation surveys

Ascaso, B.; Mei, S.; Benı́tez, N.

doi:10.1093/mnras/stv1597

Cited by 23 publications

(36 citation statements)

References 81 publications

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“…Such difficulties are ultimately due to the photometric redshift uncertainties which are significantly larger than the cluster scales, especially at the faint end of the galaxy luminosity function and at high (z 1.5) redshifts. Typical statistical photometric redshift uncertainties for accurate photometric redshift estimates are in fact in the range ∼ 0.03 − 0.05(1 + z) for galaxies with H-band magnitudes H < 24 and redshift z 2.5 (Skelton et al 2014;Ascaso et al 2015;Bezanson et al 2016).…”

Section: Photometric Informationmentioning

confidence: 99%

“…The combined use of multiwavelength infraredoptical-ultraviolet surveys such as SDSS, DES, and Euclid will ultimately imply photometric redshifts with an accuracy of σ(∆z/(1 + z s )) 0.03 − 0.05 up to z ∼ 2 (Ascaso et al 2015, and Euclid Red Book 2 ), where ∆z = z p − z s . Here z p and z s denote photometric and spectroscopic redshifts, respectively.…”

Section: Simulated Galaxy and Halo Catalogsmentioning

confidence: 99%

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A new method to assign galaxy cluster membership using photometric redshifts

Castignani

Benoist

2016

A&A

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We introduce a new effective strategy to assign group and cluster membership probabilities Pmem to galaxies using photometric redshift information. Large dynamical ranges both in halo mass and cosmic time are considered. The method takes into account the magnitude distribution of both cluster and field galaxies as well as the radial distribution of galaxies in clusters using a non-parametric formalism, and relies on Bayesian inference to take photometric redshift uncertainties into account. We successfully test the method against 1, 208 galaxy clusters within redshifts z = 0.05−2.58 and masses 10 13.29−14.80 M drawn from wide field simulated galaxy mock catalogs mainly developed for the forthcoming Euclid mission. Median purity and completeness values of (55 +17 −15 )% and (95 +5 −10 )% are reached for galaxies brighter than 0.25L * within r200 of each simulated halo and for a statistical photometric redshift accuracy σ((zs −zp)/(1+zs)) = 0.03.The mean values p = 56% and c = 93% are consistent with the median and have negligible sub-percent uncertainties. Accurate photometric redshifts (σ((zs − zp)/(1 + zs)) 0.05) and robust estimates for the cluster redshift and cluster center coordinates are required. The dependence of the assignments on photometric redshift accuracy, galaxy magnitude and distance from the halo center, and halo properties such as mass, richness, and redshift are investigated. Variations in the mean values of both purity and completeness are globally limited to a few percent. The largest departures from the mean values are found for galaxies associated with distant z 1.5 halos, faint (∼ 0.25 L * ) galaxies, and those at the outskirts of the halo (at cluster-centric projected distances ∼ r200) for which the purity is decreased, ∆p 20% at most, with respect to the mean value. The proposed method is applied to derive accurate richness estimates. A statistical comparison between the true (Ntrue) vs. estimated richness (λ = Pmem) yields on average to unbiased results, Log(λ/Ntrue) = −0.0051 ± 0.15. The scatter around the mean of the logarithmic difference between λ and the halo mass is 0.10 dex for massive halos 10 14.5 M . Our estimates could therefore be useful to constrain the cluster mass function and to calibrate independent cluster mass estimates such as those obtained from weak lensing, Sunyaev-Zel'dovich, and X-ray studies. Our method can be applied to any list of galaxy clusters or groups in both present and forthcoming surveys such as SDSS, CFHTLS, Pan-STARRS, DES, LSST, and Euclid.

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Section: Photometric Informationmentioning

confidence: 99%

Section: Simulated Galaxy and Halo Catalogsmentioning

confidence: 99%

A new method to assign galaxy cluster membership using photometric redshifts

Castignani

Benoist

2016

A&A

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“…been applied to previous work (Arnalte-Mur et al 2014;Zandivarez et al 2014;Ascaso et al 2015), will be fully detailed in a future publication (Benitez et al in prep).…”

Section: Light-cone Mock Cataloguementioning

confidence: 99%

Galaxy clusters and groups in the ALHAMBRA survey

Ascaso

Benı́tez

Fernández-Soto

et al. 2015

Mon. Not. R. Astron. Soc.

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We present a catalogue of 348 galaxy clusters and groups with 0.2 < z < 1.2 selected in the 2.78 deg 2 ALHAMBRA Survey. The high precision of our photometric redshifts, close to 1%, and the wide spread of the seven ALHAMBRA pointings ensure that this catalogue has better mass sensitivity and is less affected by cosmic variance than comparable samples.The detection has been carried out with the Bayesian Cluster Finder (BCF), whose performance has been checked in ALHAMBRA-like light-cone mock catalogues. Great care has been taken to ensure that the observable properties of the mocks photometry accurately correspond to those of real catalogues. From our simulations, we expect to detect galaxy clusters and groups with both 70% completeness and purity down to dark matter halo masses of M h ∼ 3 × 10 13 M ⊙ for z < 0.85. Cluster redshifts are expected to be recovered with ∼ 0.6% precision for z < 1. We also expect to measure cluster masses with σ M h |M * CL ∼ 0.25 − 0.35 dex precision down to ∼ 3 × 10 13 M ⊙ , masses which are 50% smaller than those reached by similar work.We have compared these detections with previous optical, spectroscopic and Xrays work, finding an excellent agreement with the rates reported from the simulations. We have also explored the overall properties of these detections such as the presence of a colour-magnitude relation, the evolution of the photometric blue fraction and the clustering of these sources in the different ALHAMBRA fields. Despite the small numbers, we observe tentative evidence that, for a fixed stellar mass, the environment is playing a crucial role at lower redshifts (z<0.5).

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“…The photometric redshift uncertainties in upcoming surveys are expected to be within 0.03 < σ z /(1 + z) < 0.05 for galaxies and within 0.01 < σ z /(1 + z) < 0.03 for clusters (Ascaso et al 2015). Ideally, the error on the cluster redshift should scale proportionally to N mem −1/2 (where N mem is the number of cluster members), therefore for clusters with ten detected members the error would be reduced by a factor three; but of course contamination from non-member galaxies will affect the redshift estimate.…”

Section: Generation Of the Photometric Redshift Distribution Of Haloesmentioning

confidence: 93%

Evolution of the real-space correlation function from next generation cluster surveys

Sridhar

Maurogordato

Benoist

et al. 2017

A&A

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Context. The next generation of galaxy surveys will provide cluster catalogues probing an unprecedented range of scales, redshifts, and masses with large statistics. Their analysis should therefore enable us to probe the spatial distribution of clusters with high accuracy and derive tighter constraints on the cosmological parameters and the dark energy equation of state. However, for the majority of these surveys, redshifts of individual galaxies will be mostly estimated by multiband photometry which implies nonnegligible errors in redshift resulting in potential difficulties in recovering the real-space clustering. Aims. We investigate to which accuracy it is possible to recover the real-space two-point correlation function of galaxy clusters from cluster catalogues based on photometric redshifts, and test our ability to detect and measure the redshift and mass evolution of the correlation length r 0 and of the bias parameter b(M, z) as a function of the uncertainty on the cluster redshift estimate. Methods. We calculate the correlation function for cluster sub-samples covering various mass and redshift bins selected from a 500 deg 2 light-cone limited to H < 24. In order to simulate the distribution of clusters in photometric redshift space, we assign to each cluster a redshift randomly extracted from a Gaussian distribution having a mean equal to the cluster cosmological redshift and a dispersion equal to σ z. The dispersion is varied in the range σ (z=0) = σz 1+zc = 0.005, 0.010, 0.030 and 0.050, in order to cover the typical values expected in forthcoming surveys. The correlation function in real-space is then computed through estimation and deprojection of w p (r p). Four mass ranges (from M halo > 2 × 10 13 h −1 M to M halo > 2 × 10 14 h −1 M) and six redshift slices covering the redshift range [0, 2] are investigated, first using cosmological redshifts and then for the four photometric redshift configurations. Results. From the analysis of the light-cone in cosmological redshifts we find a clear increase of the correlation amplitude as a function of redshift and mass. The evolution of the derived bias parameter b(M, z) is in fair agreement with theoretical expectations. We calculate the r 0 − d relation up to our highest mass, highest redshift sample tested (z = 2, M halo > 2 × 10 14 h −1 M). From our pilot sample limited to M halo > 5 × 10 13 h −1 M (0.4 < z < 0.7), we find that the real-space correlation function can be recovered by deprojection of w p (r p) within an accuracy of 5% for σ z = 0.001 × (1 + z c) and within 10% for σ z = 0.03 × (1 + z c). For higher dispersions (besides σ z > 0.05 × (1 + z c)), the recovery becomes noisy and difficult. The evolution of the correlation in redshift and mass is clearly detected for all σ z tested, but requires a large binning in redshift to be detected significantly between individual redshift slices when increasing σ z. The best-fit parameters (r 0 and γ) as well as the bias obtained from the deprojection method for all σ z are within the 1σ uncertainty of t...

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Apples to apples A²– I. Realistic galaxy simulated catalogues and photometric redshift predictions for next-generation surveys

Cited by 23 publications

References 81 publications

A new method to assign galaxy cluster membership using photometric redshifts

A new method to assign galaxy cluster membership using photometric redshifts

Galaxy clusters and groups in the ALHAMBRA survey

Evolution of the real-space correlation function from next generation cluster surveys

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Apples to apples A2– I. Realistic galaxy simulated catalogues and photometric redshift predictions for next-generation surveys

Cited by 23 publications

References 81 publications

A new method to assign galaxy cluster membership using photometric redshifts

A new method to assign galaxy cluster membership using photometric redshifts

Galaxy clusters and groups in the ALHAMBRA survey

Evolution of the real-space correlation function from next generation cluster surveys

Contact Info

Product

Resources

About

Apples to apples A²– I. Realistic galaxy simulated catalogues and photometric redshift predictions for next-generation surveys