Linear bias forecasts for emission line cosmological surveys

Merson, A.; Smith, Alex; Benson, Andrew; Wang, Yun; Baugh, C. M.

doi:10.1093/mnras/stz1204

Cited by 32 publications

(45 citation statements)

References 106 publications

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“…This behaviour is typically seen in the models when galaxies are selected by their star formation rate instead of a property that correlates more closely with stellar mass (Contreras et al 2013;Cowley et al 2016;Jiménez et al 2019). More recently Gonzalez-Perez et al (2018) found similar behaviour for the HOD of emission-line galaxies selected by the colour-magnitude cuts that will be used by the DESI emission-line galaxy survey (see also Merson et al 2019 andGonzalez-Perez et al 2020). The LRG population is dominated by central galaxies and contains a satellite fraction of f sat ∼ 0.10-0.04 in the redshift range = 0.6−1, where the mean number of satellites N s is close to a power law.…”

Section: S E L E C T I O N O F L U M I N O U S R E D G a L A X I E Smentioning

confidence: 69%

“…In the case of the most massive haloes, we extrapolate beyond the halo mass range of the HOD values; we do not have robust predictions for these haloes from the PMILL simulation due to its smaller volume compared to the GLAM boxes. This method was used recently by Merson et al (2019), where the authors extracted the HOD of H α galaxies from the GALACTICUS SAM catalogue (Benson 2012;Merson et al 2018), and used this to populate the Millennium-MXXL halo light-cone from Smith et al (2017).…”

Section: Galaxy Clustering In the Pmill And Glam Simulationsmentioning

confidence: 99%

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Building a digital twin of a luminous red galaxy spectroscopic survey: galaxy properties and clustering covariance

Hernández‐Aguayo

Prada

Baugh

et al. 2021

Monthly Notices of the Royal Astronomical Society

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Upcoming surveys will use a variety of galaxy selections to map the large-scale structure of the Universe. It is important to make accurate predictions for the properties and clustering of such galaxies, including the errors on these statistics. Here, we describe a novel technique which uses the semi-analytical model of galaxy formation galform, embedded in the high-resolution N-body Planck-Millennium simulation, to populate a thousand halo catalogues generated using the Parallel-PM N-body glam code. Our hybrid scheme allows us to make clustering predictions on scales that cannot be modelled in the original N-body simulation. We focus on luminous red galaxies (LRGs) selected in the redshift range z = 0.6 − 1 from the galform output using similar colour-magnitude cuts in the r, z and W1 bands to those that will be applied in the Dark Energy Spectroscopic Instrument (DESI) survey, and call this illustrative sample ‘DESI-like’ LRGs. We find that the LRG-halo connection is non-trivial, leading to the prediction of a non-standard halo occupation distribution; in particular, the occupation of central galaxies does not reach unity for the most massive haloes, and drops with increasing mass. The glam catalogues reproduce the abundance and clustering of the LRGs predicted by galform. We use the glam mocks to compute the covariance matrices for the two-point correlation function and power spectrum of the LRGs and their background dark matter density field, revealing important differences. We also make predictions for the linear-growth rate and the baryon acoustic oscillations distances at z = 0.6, 0.74 and 0.93. All ‘DESI-like’ LRG catalogues are made publicly available.

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Section: S E L E C T I O N O F L U M I N O U S R E D G a L A X I E Smentioning

confidence: 69%

Section: Galaxy Clustering In the Pmill And Glam Simulationsmentioning

confidence: 99%

Building a digital twin of a luminous red galaxy spectroscopic survey: galaxy properties and clustering covariance

Hernández‐Aguayo

Prada

Baugh

et al. 2021

Monthly Notices of the Royal Astronomical Society

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“…The sky coverage is also 15000 deg 2 , and the expected number density of objects will ben g ≃ 2000 sources per deg 2 . We fit the number density distribution using the model 3 data by [76] and assume as galaxy bias redshift evolution b G ðzÞ ¼ 0.7 þ 0.7z, following the fitting for emission line object from [78]. For the tomography, we divide the survey in nine bins with the same redshift width (Δz ¼ 0.1), and the redshift accuracy is assumed to be σ z ¼ 0.001ð1 þ zÞ.…”

Section: Euclid-like Surveysmentioning

confidence: 99%

Cosmological parameter forecasts by a joint 2D tomographic approach to CMB and galaxy clustering

et al. 2021

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The cross-correlation between the cosmic microwave background (CMB) fields and matter tracers carries important cosmological information. In this paper, we forecast by a signal-to-noise ratio analysis the information contained in the cross-correlation of the CMB anisotropy fields with source counts for future cosmological observations and its impact on cosmological parameters uncertainties, using a joint tomographic analysis. We include temperature, polarization, and lensing for the CMB fields and galaxy number counts for the matter tracers. We consider Planck-like, the Simons Observatory, LiteBIRD, and CMB-S4 specifications for CMB, and Euclid-like, Vera C. Rubin Observatory, SPHEREx, EMU, and SKA1 for future galaxy surveys. We restrict ourselves to quasilinear scales in order to deliver results that are free as much as possible from the uncertainties in modeling nonlinearities. We forecast by a Fisher matrix formalism the relative importance of the cross-correlation of source counts with the CMB in the constraints on the parameters for several cosmological models. We obtain that the CMB-number counts cross-correlation can improve the dark energy figure of merit (FOM) at most up to a factor ∼2 for LiteBIRD þ CMB-S4 × SKA1 compared to the uncorrelated combination of both probes and will enable the Euclid-like photometric survey to reach the highest FOM among those considered here. We also forecast how CMB-galaxy clustering cross-correlation could increase the FOM of the neutrino sector, also enabling a statistically significant (≳3σ for LiteBIRD þ CMB-S4 × SPHEREx) detection of the minimal neutrino mass allowed in a normal hierarchy by using quasilinear scales only. Analogously, we find that the uncertainty in the local primordial non-Gaussianity could be as low as σðf NL Þ ∼ 1.5-2 by using two-point statistics only with the combination of CMB and radio surveys, such as EMU and SKA1. Further, we quantify how cross-correlation will help characterizing the galaxy bias. Our results highlight the additional constraining power of the cross-correlation between CMB and galaxy clustering from future surveys, which is mainly based on quasilinear scales and therefore, sufficiently robust to nonlinear effects.

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“…This yields as total number density of objectsn g ¼ 2039 sources per deg 2 , for which we introduce a 50% factor due to the Euclid completeness and purity. We assume a bias evolution function b g ðzÞ ¼ 0.7 þ 0.7z according to the fitting for Hα emission line object from [25]. The redshift accuracy is characterized by a dispersion σ z ¼ 0.001ð1 þ zÞ.…”

Section: Euclid-like Spectroscopic Surveymentioning

confidence: 99%

Measuring lensing ratios with future cosmological surveys

et al. 2020

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The ratio between the CMB lensing/galaxy counts and the galaxy shear/galaxy counts cross-correlations combines the information from different cosmological probes to infer cosmographic measurements that are less dependent on astrophysical uncertainties and can constrain the geometry of the Universe. We discuss the future perspectives for the measurement of this lensing ratio as previously introduced, i.e., with the use of the Limber and flat-sky approximations and neglecting all the effects on the galaxy survey from observing on the past light cone. We then show how the cosmological information in this estimator is affected by the Limber approximation and by the inclusion of the redshift space distortions (RSD) and lensing magnification contributions to the galaxy number counts. We find that the lensing magnification contribution induces a multipole dependence of the lensing ratio that we show to be detectable at a statistical significant level combining post-Planck CMB surveys and a Euclid-like experiment. We propose an improved estimator which takes into account this angular scale dependence. Using this extended formalism, we present forecasts for upcoming and future cosmological surveys, and we show at which extent the lensing ratio information can improve the CMB constraints on cosmological parameters. We get that for extended cosmological models where the neutrino mass, the spatial curvature and the dark energy equation of state are allowed to vary, the constraints from Planck on these parameters and on H 0 can be reduced by ∼40% with the inclusion of a single lensing ratio and by ∼60%-70% adding the joint measurement of 9 lensing ratios with a Euclid-like survey. We also find that neglecting the contribution from lensing magnification can induce a bias on the derived cosmological parameters in a combined analysis.

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Linear bias forecasts for emission line cosmological surveys

Cited by 32 publications

References 106 publications

Building a digital twin of a luminous red galaxy spectroscopic survey: galaxy properties and clustering covariance

Building a digital twin of a luminous red galaxy spectroscopic survey: galaxy properties and clustering covariance

Cosmological parameter forecasts by a joint 2D tomographic approach to CMB and galaxy clustering

Measuring lensing ratios with future cosmological surveys

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