Dark energy survey year 1 results: Constraining baryonic physics in the Universe

ABSTRACT Measurements of large-scale structure are interpreted using theoretical predictions for the matter distribution, including potential impacts of baryonic physics. We constrain the feedback strength of baryons jointly with cosmology using weak lensing and galaxy clustering observables (3 × 2pt) of Dark Energy Survey (DES) Year 1 data in combination with external information from baryon acoustic oscillations (BAO) and Planck cosmic microwave background polarization. Our baryon modelling is informed by a set of hydrodynamical simulations that span a variety of baryon scenarios; we span this space via a Principal Component (PC) analysis of the summary statistics extracted from these simulations. We show that at the level of DES Y1 constraining power, one PC is sufficient to describe the variation of baryonic effects in the observables, and the first PC amplitude (Q1) generally reflects the strength of baryon feedback. With the upper limit of Q1 prior being bound by the Illustris feedback scenarios, we reach $\sim 20{{\ \rm per\ cent}}$ improvement in the constraint of $S_8=\sigma _8(\Omega _{\rm m}/0.3)^{0.5}=0.788^{+0.018}_{-0.021}$ compared to the original DES 3 × 2pt analysis. This gain is driven by the inclusion of small-scale cosmic shear information down to 2.5 arcmin, which was excluded in previous DES analyses that did not model baryonic physics. We obtain $S_8=0.781^{+0.014}_{-0.015}$ for the combined DES Y1+Planck EE+BAO analysis with a non-informative Q1 prior. In terms of the baryon constraints, we measure $Q_1=1.14^{+2.20}_{-2.80}$ for DES Y1 only and $Q_1=1.42^{+1.63}_{-1.48}$ for DESY1+Planck EE+BAO, allowing us to exclude one of the most extreme AGN feedback hydrodynamical scenario at more than 2σ.

Download Full-text

Combination of cluster number counts and two-point correlations: validation on mock Dark Energy Survey

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab239 ◽

2021 ◽

Vol 502 (3) ◽

pp. 4093-4111

Author(s):

Chun-Hao To ◽

Elisabeth Krause ◽

Eduardo Rozo ◽

Hao-Yi Wu ◽

Daniel Gruen ◽

...

Keyword(s):

Dark Energy ◽

Large Scale ◽

Galaxy Cluster ◽

Small Scale ◽

Cluster Number ◽

Dark Energy Survey ◽

Simulated Likelihood ◽

Significant Difference ◽

Systematic Effects ◽

Energy Survey

ABSTRACT We present a method of combining cluster abundances and large-scale two-point correlations, namely galaxy clustering, galaxy–cluster cross-correlations, cluster autocorrelations, and cluster lensing. This data vector yields comparable cosmological constraints to traditional analyses that rely on small-scale cluster lensing for mass calibration. We use cosmological survey simulations designed to resemble the Dark Energy Survey Year 1 (DES-Y1) data to validate the analytical covariance matrix and the parameter inferences. The posterior distribution from the analysis of simulations is statistically consistent with the absence of systematic biases detectable at the precision of the DES-Y1 experiment. We compare the χ2 values in simulations to their expectation and find no significant difference. The robustness of our results against a variety of systematic effects is verified using a simulated likelihood analysis of DES-Y1-like data vectors. This work presents the first-ever end-to-end validation of a cluster abundance cosmological analysis on galaxy catalogue level simulations.

Download Full-text

Dark energy survey internal consistency tests of the joint cosmological probes analysis with posterior predictive distributions

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab526 ◽

2021 ◽

Vol 503 (2) ◽

pp. 2688-2705

Author(s):

C Doux ◽

E Baxter ◽

P Lemos ◽

C Chang ◽

A Alarcon ◽

...

Keyword(s):

Dark Energy ◽

Internal Consistency ◽

Goodness Of Fit ◽

Small Scale ◽

P Value ◽

Posterior Predictive Distribution ◽

Data Set ◽

Dark Energy Survey ◽

Data Vector ◽

Energy Survey

ABSTRACT Beyond ΛCDM, physics or systematic errors may cause subsets of a cosmological data set to appear inconsistent when analysed assuming ΛCDM. We present an application of internal consistency tests to measurements from the Dark Energy Survey Year 1 (DES Y1) joint probes analysis. Our analysis relies on computing the posterior predictive distribution (PPD) for these data under the assumption of ΛCDM. We find that the DES Y1 data have an acceptable goodness of fit to ΛCDM, with a probability of finding a worse fit by random chance of p = 0.046. Using numerical PPD tests, supplemented by graphical checks, we show that most of the data vector appears completely consistent with expectations, although we observe a small tension between large- and small-scale measurements. A small part (roughly 1.5 per cent) of the data vector shows an unusually large departure from expectations; excluding this part of the data has negligible impact on cosmological constraints, but does significantly improve the p-value to 0.10. The methodology developed here will be applied to test the consistency of DES Year 3 joint probes data sets.

Download Full-text

Dark Energy Survey Year 1 results: measurement of the baryon acoustic oscillation scale in the distribution of galaxies to redshift 1

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/sty3351 ◽

2018 ◽

Vol 483 (4) ◽

pp. 4866-4883 ◽

Cited By ~ 30

Author(s):

T M C Abbott ◽

F B Abdalla ◽

A Alarcon ◽

S Allam ◽

F Andrade-Oliveira ◽

...

Keyword(s):

Dark Energy ◽

Cold Dark Matter ◽

Angular Diameter ◽

Acoustic Oscillations ◽

Distance Measurements ◽

Angular Diameter Distance ◽

Dark Energy Survey ◽

Trade Offs ◽

Physical Scale ◽

Energy Survey

ABSTRACT We present angular diameter distance measurements obtained by locating the baryon acoustic oscillations (BAO) scale in the distribution of galaxies selected from the first year of Dark Energy Survey data. We consider a sample of over 1.3 million galaxies distributed over a footprint of 1336 deg2 with 0.6 < $z$photo < 1 and a typical redshift uncertainty of 0.03(1 + $z$). This sample was selected, as fully described in a companion paper, using a colour/magnitude selection that optimizes trade-offs between number density and redshift uncertainty. We investigate the BAO signal in the projected clustering using three conventions, the angular separation, the comoving transverse separation, and spherical harmonics. Further, we compare results obtained from template-based and machine-learning photometric redshift determinations. We use 1800 simulations that approximate our sample in order to produce covariance matrices and allow us to validate our distance scale measurement methodology. We measure the angular diameter distance, DA, at the effective redshift of our sample divided by the true physical scale of the BAO feature, rd. We obtain close to a 4 per cent distance measurement of DA($z$eff = 0.81)/rd = 10.75 ± 0.43. These results are consistent with the flat Λ cold dark matter concordance cosmological model supported by numerous other recent experimental results.

Download Full-text

The WiggleZ Dark Energy Survey: small-scale clustering of Lyman-break galaxies atz< 1

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2009.14447.x ◽

2009 ◽

Vol 395 (1) ◽

pp. 240-254 ◽

Cited By ~ 22

Author(s):

Chris Blake ◽

Russell J. Jurek ◽

Sarah Brough ◽

Matthew Colless ◽

Warrick Couch ◽

...

Keyword(s):

Dark Energy ◽

Small Scale ◽

Dark Energy Survey ◽

Lyman Break Galaxies ◽

Energy Survey

Download Full-text

KiDS+VIKING-450 and DES-Y1 combined: Mitigating baryon feedback uncertainty with COSEBIs

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936512 ◽

2020 ◽

Vol 634 ◽

pp. A127 ◽

Cited By ~ 14

Author(s):

Marika Asgari ◽

Tilman Tröster ◽

Catherine Heymans ◽

Hendrik Hildebrandt ◽

Jan Luca van den Busch ◽

...

Keyword(s):

Dark Energy ◽

Mode Analysis ◽

Small Scale ◽

Microwave Background ◽

Cosmological Constraints ◽

Dark Energy Survey ◽

Matter Power Spectrum ◽

Λcdm Model ◽

Cosmic Shear ◽

Energy Survey

We present cosmological constraints from a joint cosmic shear analysis of the Kilo-Degree Survey (KV450) and the Dark Energy Survey (DES-Y1), which were conducted using Complete Orthogonal Sets of E/B-Integrals (COSEBIs). With COSEBIs, we isolated any B-modes that have a non-cosmic shear origin and demonstrate the robustness of our cosmological E-mode analysis as no significant B-modes were detected. We highlight how COSEBIs are fairly insensitive to the amplitude of the non-linear matter power spectrum at high k-scales, mitigating the uncertain impact of baryon feedback in our analysis. COSEBIs, therefore, allowed us to utilise additional small-scale information, improving the DES-Y1 joint constraints on S8 = σ8(Ωm/0.3)0.5 and Ωm by 20%. By adopting a flat ΛCDM model we find S8 = 0.755−0.021+0.019, which is in 3.2σ tension with the Planck Legacy analysis of the cosmic microwave background.

Download Full-text

Galaxy formation and evolution with the Dark Energy Survey

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313004523 ◽

2012 ◽

Vol 8 (S295) ◽

pp. 137-140

Author(s):

Diego Capozzi ◽

Daniel Thomas ◽

Claudia Maraston ◽

Luke J. M. Davies

Keyword(s):

Dark Energy ◽

Galaxy Evolution ◽

Galaxy Formation ◽

Large Scale ◽

Time Range ◽

Data Set ◽

Dark Energy Survey ◽

Galaxy Formation And Evolution ◽

Formation And Evolution ◽

Energy Survey

AbstractThe Dark Energy Survey (DES) will be the new state-of the-art in large-scale galaxy imaging surveys. With 5,000 deg2, it will cover an area of the sky similar to SDSS-II, but will go over two magnitudes deeper, reaching 24th magnitude in all four optical bands (griz). DES will further provide observations in the redder Y-band and will be complemented with VISTA observations in the near-infrared bands JHK. Hence DES will furnish an unprecedented combination of sky and wavelength coverage and depth, unreached by any of the existing galaxy surveys. The very nature of the DES data set – large volume at intermediate photometric depth – allows us to probe galaxy formation and evolution within a cosmic-time range of ~ 10 Gyr and in different environments. In fact there will be many galaxy clusters available for galaxy evolution studies, given that one of the main aims of DES is to use their abundance to constrain the equation of state of dark energy. The X-ray follow up of these clusters, coupled with the use of gravitational lensing, will provide very precise measures of their masses, enabling us to study in detail the influence of the environment on galaxy formation and evolution processes. DES will leverage the study of these processes by allowing us to perform a detailed investigation of the galaxy luminosity and stellar mass functions and of the relationship between dark and baryonic matter as described by the Halo Occupation Distribution.

Download Full-text

The WiggleZ Dark Energy Survey: testing the cosmological model with baryon acoustic oscillations at z= 0.6

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2011.19077.x ◽

2011 ◽

Vol 415 (3) ◽

pp. 2892-2909 ◽

Cited By ~ 174

Author(s):

Chris Blake ◽

Tamara Davis ◽

Gregory B. Poole ◽

David Parkinson ◽

Sarah Brough ◽

...

Keyword(s):

Dark Energy ◽

Cosmological Model ◽

Acoustic Oscillations ◽

Dark Energy Survey ◽

Baryon Acoustic Oscillations ◽

Energy Survey

Download Full-text

Ridges in the Dark Energy Survey for cosmic trough identification

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3204 ◽

2020 ◽

Vol 500 (1) ◽

pp. 859-870

Author(s):

Ben Moews ◽

Morgan A Schmitz ◽

Andrew J Lawler ◽

Joe Zuntz ◽

Alex I Malz ◽

...

Keyword(s):

Dark Energy ◽

Large Scale ◽

Mass Density ◽

Mean Shift ◽

Large Scale Structure ◽

Wasserstein Distance ◽

Scale Structure ◽

Weak Lensing ◽

Dark Energy Survey ◽

Energy Survey

ABSTRACT Cosmic voids and their corresponding redshift-projected mass densities, known as troughs, play an important role in our attempt to model the large-scale structure of the Universe. Understanding these structures enables us to compare the standard model with alternative cosmologies, constrain the dark energy equation of state, and distinguish between different gravitational theories. In this paper, we extend the subspace-constrained mean shift algorithm, a recently introduced method to estimate density ridges, and apply it to 2D weak lensing mass density maps from the Dark Energy Survey Y1 data release to identify curvilinear filamentary structures. We compare the obtained ridges with previous approaches to extract trough structure in the same data, and apply curvelets as an alternative wavelet-based method to constrain densities. We then invoke the Wasserstein distance between noisy and noiseless simulations to validate the denoising capabilities of our method. Our results demonstrate the viability of ridge estimation as a precursor for denoising weak lensing observables to recover the large-scale structure, paving the way for a more versatile and effective search for troughs.

Download Full-text