Euclid SPV3 meeting

20 mars 2023, 13:30 → 23 mars 2023, 16:30 Europe/Paris

salle des séminaires (Institut d'Astrophysique de Paris)

This meeting is entirely dedicated to the Third Science Performance Verification exercice (SPV3) which has been launch March 17 2021 under the responsibility of F. Bernardeau, H. Aussel and P.-A. Frugier. 

This meeting has two main objectives, 

• present the SPV3 Level1 results and lesson learnt
• consolidate the roadmap for Level 2 results 

It will be organized in sessions with invited talks and submitted talks. It should also make room for discussion sessions.

The meeting is restricted to EC members. It will be in hybrid format but on site participation is encouraged to facilitate face to face interactions.

• Registration is open till Feb 26 for in person participants. It is free but mandatory. Participants will be offered coffee breasks and lunches (cold meals in the IAP entrance hall). It is their responsibility however to find accomodation.
• Abstract submission is open till March 10. Junior colleagues are particularly encouraged to submit propositions for talks. Duration of talks will be adjusted depending on schedule. They will be a priori 30' long (with questions).

Code of Conduct: all  participants are requested to comply with the EC Code of Conduct.

Local Organization Committee:

• Nitaya Singsengsouvanh, singseng@iap.fr, contact person 
• Fred Magnard
• Simon Berquez
• Francis Bernardeau
• Karim benabed 

 

Practical information (detailed agenda, connection links, slack, etc.) to be foound here (restricted to EC members),

https://euclid.roe.ac.uk/projects/spv03/wiki/20210317SPV3Paris_

 

lundi 20 mars

13:30 Welcome coffee and registration

1 Welcome talks and presentation of the meeting

Orateur: Francis Bernardeau (IPhT Saclay)

The 3x2pt Weak lensing and Galay photometric probe, reference model and performances

Main session with presentations by:

Président de session: Vincenzo Cardone

16:00 Coffee break

2 The Flagship Simulation efforts and roadmap

• Presentation of the Flagship Wide by P. Fosalba
• Presentation of the Flagship Deep by M. Bolzonella

Orateurs: Micol Bolzonella, Pablo Fosalba

mardi 21 mars

Contributions: PSF reconstruction (TBC)

Président de session: Pierre-Antoine Frugier

The Galaxy Clustering Spec (GCsp) probe, reference model and performances

Presentation of the GC spectroscopic reference model its performances in terms of FoM, dependence on priors, etc.

Président de session: Martin Crocce

3 Validation of the MontePython forecasting tools with Euclid synthetic likelihoods

We expand and adjust the synthetic Euclid likelihoods of the MontePython software in order to match the exact recipes used
in previous Euclid Fisher matrix forecasts for several probes: weak lensing cosmic shear, photometric galaxy clustering, the cross-
correlation between the latter observables, and spectroscopic galaxy clustering. We also establish which precision settings are
required when running the Einstein–Boltzmann solvers CLASS and CAMB in the context of Euclid.
We show that such MontePython forecasts agree very well with previous Fisher forecasts published by the Euclid Collabo-
ration.
Moreover, to establish the validity of the Gaussian approximation, we show that the Fisher matrix marginal
error contours coincide with the credible regions obtained when running Monte Carlo Markov Chains with MontePython while using
the exact same synthetic likelihoods.
These ersatz likelihoods can be used to perform more accurate MCMC forecasts on different parameter extensions and survey settings for various modelling scenarios in preparation for the real analysis with the official likelihood code CLOE.

Orateur: Dr Santiago Casas (TTK, RWTH Aachen University)

10:30 Coffee break

IST-NL: status report of non-linear models and covariances

Président de session: Alkistis Pourtsidou

4 Using cross correlation between 2D and 3D data in Euclid

Euclid will have the unique feature of simultaneously having 2D probes with 3*2pt but also 3D data on the same areas of the sky. In this presentation I will discuss how to use this information in a cost-effective way and the type of gain that can be forecasted.

Orateur: ALAIN BLANCHARD (IRAP , OMP)

13:00 Lunch break

Galaxy Clustering E2E, status and roadmap

5 A novel method to combine clustering and lensing analyses for spectroscopic and photometric samples

I present a new technique for the measurement of the growth of cosmic structures via the power spectrum of weak lensing cosmic shear, which can be straightforwardly combined to classic bias and growth measurements from clustering. It is based on a template-fitting approach, where a redshift-dependent amplitude of lensing modulates a fixed template power spectrum. To allow for tracking the redshift evolution of the signal, the method makes use of the Bernardeay-Nishimishi-Taruya transform, which allows for a localisation of the lensing kernel. I show that this method is able to correctly reconstruct Ωσ8 at the percent level across redshift, thus allowing us to measure the growth of structures unbiased by observing discrete tracers. Moreover, I only make use of mea- surements on linear scales. I also demonstrate that the method is robust against an incorrect choice of cosmological parameters in the template, thanks to the inclusion of an Alcock-Paczyński parameter.

Orateur: Stefano Camera (U. Turin)

16:00 Coffee break

PSF tool kit, status and performances

Président de session: Lance Miller

6 PSF modelling for SPV3

We describe the status of PSF modelling for SPV3, providing updates and features that may be used in multi-faceted investigations.

Orateur: Lance Miller (Oxford University)

7 Propagating PSF errors into shear biases

We are currently working on propagating expected Euclid PSF errors into shear biases for the WL E2E box as part of the SPV3 exercise. Given some base and perturbed PSFs generated using the PSF Toolkit, we numerically estimate the multiplicative and additive shear biases for galaxies in the Flagship 2 mock catalogue. We currently consider two sources of PSF error: firstly, errors in the PSF modelling across the survey footprint; and secondly, PSF errors arising due to imperfect knowledge of the galaxy SEDs. For the PSF modelling errors, we consider the impact of neglecting the variation in the PSF due to changes in solar aspect angle throughout the survey, resulting in shear biases that vary across the survey footprint. For the galaxy SED errors, we consider the error in the PSF model that arises due to coarse binning and noise in the photometric galaxy SEDs that will be used in the per-galaxy PSF modelling. For both techniques, we calculate shear biases corresponding to a subset of the expected PSFs, and use PCA and kNN techniques to propagate to mock galaxies in flagship. This is ongoing work. In the future, we plan to investigate errors in the PSF calibration at the start of the mission, as well as the impact of blending of the ground-based photometry on the SED errors.

Orateur: M. Casey Cragg (U. Oxford)

mercredi 22 mars

CLOE, status and performances

Président de session: Valeria Pettorino

10:30 Coffee break

Weak Lensing End-2-End box, status and performances

Président de session: Alessio Mancini

8 Testing the impact of scale-dependent multiplicative bias on the cosmological analysis of the 3x2pt statistics for Euclid.

In this work, we study the effect of spatially-varying multiplicative bias on the cosmological parameter estimation in the combined photometric analysis of the 3x2pt statistics for a Euclid DR3 end-to-end forecast. To do so, we consider a spin-0 m-bias map characterized by a Gaussian profile angular power spectrum that has been studied in the literature. Also, we proceed with a conservative approach by choosing the most pessimistic scenario that has already been shown to give biased results exceeding the statistical error in a stage-IV cosmic shear analysis. This corresponds to a profile with a low multipole peak and large amplitude. In a pseudo-Cl analysis we perform the coupling of the m-bias map with the cosmic shear and the galaxy-galaxy lensing spectra and test their impact on the final 3x2pt cosmological analysis with an MCMC forecast for the LCDM and w0waCDM cosmologies and also applying optimistic and pessimistic scale cuts. Finally, we investigate the effect of the masked sky on the results.

Orateur: Konstantinos Tanidis (University of Oxford)

12:30 lunch break

Discussion: preparation of DR1, Science Performance point of view, chaired by Henk (TBC)

Présidents de session: Andi Taylor (tbc), Francis Bernardeau (IPhT Saclay), Henk Hoekstra

9 OU-PHZ status and Roadmap

Orateur: William Hartley

10 OU-SHE presentation and performances

Orateur: Andy Taylor

16:00 Coffee break

Contributions: Roadmap to covariances

Président de session: Carlo Giocoli

jeudi 23 mars

Discussion: requirements on SPV3 runs in the SGS

Président de session: Hervé Aussel

10:20 coffee break

General discussion, defining roadmaps

Présidents de session: Francis Bernardeau (IPhT Saclay), Hervé Aussel, Pierre-Antoine Frugier

12:30 lunch break

15:00 coffee break and departure