Participants and abstracts

AGHANIM NabilaOral
Update on XCMB working group activities
I will present the status of activities and plans for the future of the SWG "Cross-correlation with CMB"

AUSSEL HervéOral
Euclid Science Performance Verification
An update on the progress and preliminary results of Euclid SPV will be given.

La science des amas avec Euclid
Je presenterai les activités du Cluster Science Working Group.

BASSET AntoineOral
Processing Budget

CODIS SandrineOral
Modelling galaxy clustering in the large-deviation regime
In this talk, I will show how to implement a large-deviation principle to study the time-evolution of the large-scale structure of the Universe. This approach allows for analytical predictions in the mildly non-linear regime, beyond what is commonly achievable via other statistics such as correlation functions. The idea is to measure the mean cosmic densities within concentric spheres and study their joint statistics.The spherical symmetry then leads to surprisingly accurate predictions where standard calculations of perturbation theory usually break down. I will show results for the one and two-point statistics of the cosmic density field and discuss implications for future large galaxy surveys. Recent progress w.r.t galaxy biasing and primordial non-gaussianities will also be discussed if time allows.

CUILLANDRE Jean-CharlesOral
Evolutions du releve sol Euclid Wide
cf title

DE LA TORRE SylvainOral
Galaxy Clustering SWG activities

GAVAZZI RaphaelOral
Strong Lensing SWG - progress report

GOUIN celineOral
The prediction of the Gravitational Lensing signal through Hydrodynamical Cosmological Simulations
With the advent of high performance computing, it is now possible to address the problem of the complex interplay between baryons and dark matter (DM) on all relevant scales. Characterising jointly the dark and luminous matter distribution in the Universe is of prime importance to accurately probe the underlying cosmological model and to advance our understanding on the dark matter nature. In this line, I will present the predictions of the gravitational lensing signal (either strong or weak) through the light-cone of the hydrodynamical cosmological simulation Horizon-AGN (see Dubois et al. 2014). Lensing observables for both dark and baryonic matter are computed, in order to distinguish their individual impact on the total signal and, in turn, to study the physics of the bias. Moreover, by using our results, we have included to the mock photometric images, derived from the simulation (Kaviraj et al. 2017), the shear and the amplification fields induced by gravitational lensing. This will help to quantify our ability to extract the gravitational lensing signal for both dark and baryonic matter. Such forecasts are crucial in order to prepare future surveys such as Euclid or LSST.

Weak-lensing shape measurement and calibration: Application to CFIS and outlook for Euclid

HAWKEN AdamPoster
Orthogonality of void and galaxy probes of the growth rate of structure
One of the criticisms of void science is that we do not know how independent contraints on cosmological parameters using voids are from those using conventional galaxy clustering techniques. The EuclidVoid group (a sub group of the New Probes work package in the Galaxy Clustering Science Working Group) have been working to address these concerns. By measuring the growth rate of structure in simulations using both multipoles of the galaxy void cross correlation and the galaxy autocorrelation we are able to demonstrate that there is no strong covariance between the two probes.

Update on the morphology SWG
I will present a summary of the activity of the morphology SWG

ILIC StéphaneOral
The power of probe combination : constraining cosmology with Euclid and CMB data
Through its main probes, weak lensing and galaxy clustering, Euclid will provide us with unprecedented constraints on the local Universe and cosmology. On the other hand, high-quality CMB observations -- especially from the Planck satellite -- already put tight constraints on the early Universe. I will show how we can combine Euclid and CMB data and how it can yield significant improvement on the determination of cosmological parameters, especially for extensions of the LCDM model. Moreover, I will show that exploiting the information contained in the cross-correlation between Euclid and the CMB will push even further the quality of the future results.

Weak-lensing working group activities
I will give an update of weak-lensing scientific activities.

LACASA FabienOral
Non-linear effects on probe covariances
I will present analytic modeling and forecasts of how non-Gaussianity affect cosmological constraints with the large scale structure. Out of these effects, super-sample covariance (SSC) has been quite studied in the literature, and is at least approximately accounted for by current surveys (eg KiDS and DES). I will show that SSC cannot be quantified from data itself, nor with simulations of size comparable to the survey. On the other hand I will show that it can perfectly be predicted analytically, even for an arbitrary survey geometry, and it can be partially mitigated when combining probes by including 1-point statistics such as cluster number counts. Finally, if time permits, I will show that other non-linear effects are present and will likely be important to account for in the Euclid case, due to the survey probing larger sky area and depth.

NISP development status
NISP development status

MEI SimonaOral
Galaxy evolution in dense environments
We will discuss recent progress in the field of galaxy evolution in dense environment which are relevant to the preparation of the Euclid observation in this field. We will also present results from the Euclid Flagship simulation validation.

MELLIER YannickOral
Euclid mission progess report

PEEL AustinOral
Weak lensing validation of Euclid simulations
I present results from testing the weak-lensing fields in the Euclid Flagship simulation. These are compared to those of the previous MICEv2 galaxy mock.

Inter Science TaskForce (IST) Activity: forecasts for the Euclid mission
I will give an update on IST activities, concerning forecasts, ongoing and future tasks.

PROVOST LionelOral

PUJOL ArnauOral
Shear measurement bias: dependencies on methods, simulation parameters and measured parameters
We present a study of the dependencies of shear and ellipticity bias on simulation (input) and measured (output) parameters, noise, PSF anisotropy, pixel size and the model bias coming from two different and independent shape estimators. We show the bias dependencies found on input and output parameters for both methods and we identify the main dependencies and causes. We find consistent results between the two methods (given the precision of the analysis) and important dependencies on orientation and morphology properties such as flux, size and ellipticity. We also show that noise and pixelization play an important role on the bias dependences on the output properties. We find a large model bias for galaxies consisting of a bulge and a disk with different ellipticities or orientations. We also see an important coupling between several properties on the bias dependences. Because of this we need to study several properties simultaneously in order to properly understand the nature of shear bias.

SAKR ziadOral
Neutrinos, Calibration or Modified Gravity behind Cluster Count Tension.
A significant difference was found between a SZ cluster count when normalized from CMB Planck mission datasets and one using calibration determined from hydrodynamical simulations. We investigate the origin behind this discrepancy using a local X-ray cluster sample combined with CMB datasets where we left free to vary neutrinos, calibration parameter and modified gravity. We show which of these factors could bridge or not the cluster abundance gap between deep and local universe. We show also the result of an Euclid like survey forecast regarding its power to alleviate this tension.

SGS design review
It is probably too early to propose an abstract. And in fact, I leave the program committee to decide whether to attribute a talk to the SGS scientist or to devote more time to other SGS contributors (e.g. those involved in the challenges).

SCHMITZ MorganOral
Data-driven PSF estimation
Estimation of the Point Spread Function (PSF) is of paramount importance for shape measurements and, in turn, the extraction of cosmological information from the weak lensing signal. We present several methods, exisiting or currently in development, to tackle this problem in a data-driven way - that is, solely making use of the images themselves. These methods cover a range of the subproblems that arise for Euclid PSF estimation: superresolution of the PSF measurements from the stars observed in the field at Euclid resolution, spatial interpolation and extraction of monochromatic components. In addition, knowledge of the PSF can be used to perform deconvolution of the galaxy images and obtain catalogs of noiseless, deconvolved galaxy images. We show how this approach can be combined with PSF estimation to extract information relative to the PSF contained in the galaxy images.

Generalized dark matter model with the Euclid satellite
In a LCDM framework, dark energy may be described as a fluid with equation of state parameter equal to -1, and sound velocity equal to 1, while dark matter may be described as a fluid with null pressure and null sound velocity. In this talk we will focus on dark matter allowing a more general fluid description. We will first briefly provide the theoretical framework for this phenomenological approach, and present the results from state-of-the-art cosmological observations. We will then present preliminary Euclid forecasts for this model, showing the power of Euclid to improve our knowledge on dark matter properties.

ZWÖLF CarloOral
Error estimation in mass/luminosity function computation
In this talk we are going to present an original method for estimation of errors in the computation of the mass/luminosity function


CNRS UMR7095 - Institut d'Astrophysique de Paris - 98 bis boulevard Arago - 75014 Paris