HSC 3x2pt analysis in harmonic space as a precursor of the LSST-DESC

David S. Cid on behalf of the LSS WG DESC collaboration

56th Rencontres de Moriond Cosmology 2022Saturday 29th January

Project funded by LSSTC

HSC 3x2pt analysis as a precursor of LSST:outline

❏ What is the LSST-DESC?❏ Goals of the project❏ Generalities on 3x2pt analysis❏ Hyper-Suprime Cam Subaru Strategic Program data❏ Measuring 2pt functions with TXPipe ❏ Observing conditions cleaning & null-tests❏ Modeling ❏ Computing the covariance❏ Cosmological inference with Firecrown

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Large-Scale Structure Working Group

J. Sánchez, A. Nicola, D. Alonso, C. García-García, E. Longley-Philips, C. Chang, J. Zuntz, J. Ellison, I. Sevilla, E. Rykoff, E. Longley-Phillips, A.

Broussard, Zilong Du, B. Leistedt, R. Mandelbaum, H. Awan

What is the LSST-DESC?

The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) has four science pillars:

❏ Probing dark energy and dark matter❏ Taking an inventory of the solar system ❏ Exploring the transient optical sky❏ Mapping the Milky Way

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The Dark Energy Science Collaboration (DESC) focus is to study observable signatures of “dark sector” physics.

The goal is to make high precision measurements of fundamental cosmological parameters using LSST data combining - large scale structure, weak lensing, strong lensing, clusters of galaxies and supernovae.

Adapted from The LSST Dark Energy Science Collaboration: Introduction and Overview - Eric Gawiser at CosmoPalooza

** Check LSST website

We can extract cosmological information from galaxy surveys at late times measuring the galaxy positions and the dark matter distribution – accessible via weak lensing – at different redshifts

❏ Lenses – foreground sample for which positions are measured and used in clustering and gglensing.❏ Sources – background sample for which shapes are measured and used in shear and gglensing.

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Cosmology from Clustering and Weak Lensing:a 3x2pt analysis

Galaxy clustering corr( , )

Summary statistics: 3 angular two-point correlation functions → 3x2ptAdapted from Validating an end-to-end weak lensing and clustering framework for LSST - Judit Prat at CosmoPalooza

Cosmic shear corr( , )

corr( , )Galaxy-galaxy lensing

❏ Perform one of the first 3x2pt analysis in harmonic space

❏ Use Hyper-Suprime Cam (HSC) as a precursor of LSST data (deepest Stage III survey + same pipelines)

❏ Help with the development of TXPipe ❏ Explore the advantages of having the same

lens and source samples❏ Use systematics deprojection in spin-2 fields❏ Reproduce HSC cosmic shear analysis

applying DESC tools

❏ Get competitive constraints on Ωmatter vs S8 using Firecrown (work in progress…)

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HSC 3x2pt analysis as a precursor of LSST:goals

Hikage et al. 2018

Cosmic shear

❏ HSC is a suitable dataset for the LSST preparation as:➢ Uses a prototype version of the Rubin Science Pipelines for

data processing➢ Is the deepest Stage III wide-catalog available to date

❏ PDR1 collects positions and shapes…➢ Of approximately 11 million galaxies➢ Covering 136.9 deg2 of the northern hemisphere➢ Over 6 non-contiguous fields➢ Observed in 5 broad photometric bands grizy➢ Seeing in the i-band better than ~0.8”

❏ HSC-SSP PDR1 data presented in Aihara et al. 2018❏ Shear catalog following the same selection cuts as Mandelbaum

et al. 2018❏ Official N(z) but reweighted to consider lenses and sources

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Hyper-Suprime Cam Subaru Strategic Program:data

GAMA09H

XMM

VVDS

WIDE12HGAMA15H

HECTOMAP

❏ Limiting magnitude in the i-band equal to 25.6 (similar to LSST-Y1) and number density 21.8 arcmin-2 after additional cuts.

❏ No 3x2pt yet on this dataset.

Redshifts distributions from Hamana et al. 2020

Comparison between the simultaneous all-fields measurement versus individual fields measurement

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Measuring 2-point functions: TXPipe

** Warning! Preliminary results are shown at nside=512, final results will be nside=2048

➢ Measurement compatibility is checked for all z-bins and all individual fields

➢ Compatibility is found for the rest of probes, cosmic shear and galaxy-galaxy lensing

➢ Higher deviations are due to the naive covariance matrix used in this test

➢ “All” measurement is used for cosmological parameters inference

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Measuring 2-point functions: TXPipe

** Warning! Preliminary results are shown at nside=512, final results will be nside=2048

In order to separate the cosmological signal from the spurious signal introduced by observing conditions we apply the so-called deprojection method presented in Alonso et al. 2018

We consider a set of 60 (scalars & tensorials) observing condition maps for the cleaning process and perform robustness tests, such as:

➢ Correlation between observing conditions and overdensity/shapes maps

➢ Deprojection with 22 PCA maps➢ Using Planck tSZ and CMB lensing maps

for null-testing the templates9

Measuring 2-point functions: Observing conditions

Impact of the different potential contaminants and comparison with the no-deprojected measurement

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Measuring 2-point functions: Observing conditions

Firecrown is a DESC product under development. It is a modular analysis pipeline in which each stage focuses on a certain task i.e. reading the data vector or implementing a certain intrinsic alignment model

Use your own custom stages. Do you want to try some IA model? Do the code and insert it easily in the pipeline.

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Modeling choices & cosmological parameters inference:Firecrown

Credits to Joe ZuntzIn this project we use the LSST inference tool Firecrown for:

❏ Designing the modelling pipeline (obtain theory predictions)❏ Cosmological parameters inference (MCMC)

This project points to be the first 3x2pt analysis considering HSC PDR1 but previous projects have performed analysis over individual probes:

■ Galaxy clustering presented in Nicola et al. 2019■ Cosmic shear analysis presented in Nicola et al. 2020 ■ Official cosmic shear analysis presented in Hikage et al. 2018 and Hamana et al.

2020

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Modelling: set of analysis choices

Steps in our modelling process:

➢ Design galaxy clustering scale cuts➢ Test which is the suitable IA model➢ Galaxy bias modelling➢ Replicate HSC cosmic shear modelling

○ WL scale cuts 300 < l < 1900○ Non-linear matter power spectrum (halofit)○ IA - Non-Linear Alignment ○ Shear multiplicative bias○ Photo-z shift

Cosmic shear TXPipe measurement compared with the literature. Dashed lines show weak lensing scale cuts.

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Modelling: set of analysis choices

We need to define and cut scales at which our modelling does not yield a precise description i.e. non-linearities, baryonic physics

For the Weak Lensing we adopt the fiducial scale cuts ( )

For the Galaxy Clustering we follow this process:

■ Apply a scale cut at a given scale, we try ■ Look for the best-fit theory prediction ■ Compute the difference between data and theory prediction via its Δχ2

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Modelling: scale cuts

The combination of cosmological probes strengthens the statistical power when constraining our modeling parameters.

We need to consider the covariances between these probes among radial and angular separations as all of them are tracers of the same underlying overdensity field.

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Computing the covariance matrix

We account this contribution computing a Gaussian covariance matrix following a process similar to the one presented in García-García et al. 2019, Nicola et al. 2020

❏ Dominant contribution on large scales for galaxy clustering and weak lensing datasets❏ Complicated sky maps causes non-trivial correlations between different Fourier modes❏ Implemented in NaMaster and TXPipe

We are able to reproduce HSC cosmic shear analysis:

❏ We consider a new data reduction❏ We use a new and HSC independent measurement pipeline: summary

statistics are computed using DESC TXPipe tool❏ We have checked DESC Firecrown tool power on modelling❏ We use the LSST inference tool Firecrown to run MCMC chains and

set constraints to the matter abundance and the clumpsyness of matter distribution at late times (+ nuisance parameters).

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Cosmological parameter inference:Firecrown

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Cosmological parameter inference:Firecrown

Our cosmic shear analysis

Hikage et al. 2018

Revisar números

❏ TXPipe and Firecrown tools are highly advanced in their development. Key tools in this end-to-end project.

❏ HSC sample seems to be robust to scalar and tensorial observing conditions, we tested in-depth the effects of deprojection.

❏ Using these new measurement and inference tools we are able to replicate Hyper-Suprime Cam cosmological results based on the cosmic shear analysis.

❏ We are ready to join galaxy clustering and gglensing statistics to the cosmic shear results previously presented

❏ The addition of galaxy clustering and gglensing to the presented cosmic shear results will be the first 3x2pt results in harmonic space considering Hyper-Suprime Cam data

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HSC 3x2pt analysis as a precursor of LSST:summary

Take home idea

We are performing the first real data analysis using only DESC developed measurement and inference tools. LSST-DESC will be ready when data comes!

Thanks a lot for attending!

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❏ The LSST Dark Energy Science Collaboration: Introduction and Overview by Eric Gawiser at CosmoPalooza.

❏ Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data, Hikage et al. 2018 (arXiv 1809.09148)

❏ Validating and end-to-end weak lensing and clustering framework for LSST by Judit Prat at CosmoPalooza.

❏ Dark Energy Survey Year 1 Results: Multi-Probe Methodology and Simulated Likelihood Analyses, Krause et al. 2017 (arXiv 1706.09359)

❏ First Data Release of the Hyper Suprime-Cam Subaru Strategic Program, Aihara et al. 2018 (arxiv 1702.08449)

❏ The first-year shear catalog of the Subaru Hyper Suprime-Cam SSP Survey, Mandelbaum et al. 2018 (arxiv 1705.06745)

References

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❏ Cosmological constraints from cosmic shear two-point correlation functions with HSC survey first-year data, Hamana et al. 2020 (arxiv 1906.06041)

❏ A unified pseudo-Cℓ framework, Alonso et al. 2018 (arxiv 1809.09603)

❏ Tomographic galaxy clustering with the Subaru Hyper Suprime-Cam first year public data release, Nicola et al. 2019 (arxiv 1912.08209)

❏ Cosmic shear power spectra in practice, Nicola et al. 2020 (arxiv 2010.09717)

References

❏ Disconnected pseudo-Cℓ covariances for projected large-scale structure data, García-García et al. 2019 (arxiv 1906.11765)

❏ Core Cosmology Library: Precision Cosmological Predictions for LSST, Chisari et al. 2019 (arxiv 1812.05995)