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Christian Arnold05/05/2022 09:30
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Natalie Hogg (IPhT CEA-Saclay)05/05/2022 10:00
In this talk, I will introduce a novel class of interacting vacuum dark energy models, based on recasting the equation of state originally developed in the context of lattice kinetic theory by Shan & Chen (1993) as the coupling between the vacuum and cold dark matter (CDM). This coupling allows the vacuum to evolve and is nonlinear around a characteristic energy scale ρ∗, changing into a...
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Filippo Vernizzi (IPhT - CEA Saclay)05/05/2022 10:20
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Santiago Casas (CosmoStat, CEA Paris-Saclay)05/05/2022 10:40
Next-generation galaxy surveys will provide an accurate determination of the growth of large scale structures (LSS) in the Universe as a function of scale and redshift, on top of improved determinations of the background geometry. This will allow us to test, with unprecedented precision, the predictions of the most popular modified gravity models proposed in the literature, that have not been...
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Guilhem Lavaux (Institut d'Astrophysique de Paris / CNRS)05/05/2022 14:30
Cosmic variance poses limits to the analyses of the physics of the nearby Universe, notably to establish an accurate observational link between halo formation history and galaxy properties. The BORG framework offers a way out by generating constrained initial conditions which reproduce all the Large scale structures in a simulated environment with minimal effects due to cosmic variance. By...
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Jiaxi Yu (EPFL)05/05/2022 14:45
SubHalo Abundance Matching (SHAM) is an empirical method for constructing galaxy catalogues based on high-resolution N-body simulations. We apply SHAM on the UNIT simulation to simulate SDSS BOSS/eBOSS Luminous Red Galaxies (LRGs) within a wide redshift range of 0.2 < z < 1.0. Besides the typical SHAM scatter parameter σ, we include v smear and Vceil to take into account the redshift...
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Antoine Rocher (IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur- Yvette, France)05/05/2022 15:00
We present the study of the dark matter (DM) halo-galaxy connection of the emission line galaxies (ELGs) in the Dark Energy Spectroscopic Instrument (DESI) survey. We use Halo Occupation Distribution (HOD) models to reproduce the clustering of the DESI survey validation (SV) data. We first present the results of fits to the projected correlation function (wp), and then improvements brought by...
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Chotipan Boonkongkird (Sorbonne University)05/05/2022 15:15
The inference of cosmological quantities needs accurate and large cosmological simulations. Yet, the computational time takes millions of CPU hours for a modest coverage in cosmological scales ($~(100 Mpc/h)^3$). This ML method could have a decisive impact on the results derived from QSO surveys, e.g., SDSS3/4 data, which has a resolution power of $R=1500$ and $R=2000$. But it could be...
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Alexie Leauthaud05/05/2022 17:00
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Eric Armengaud (IRFU - CEA)06/05/2022 09:00
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Dr Julian Adamek (University of Zurich)06/05/2022 09:30
TBD Neutrinos
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ting tan06/05/2022 09:45
The Lyman-α forest is detected as the series of absorption lines in the quasar spectra, caused by the Lyman-α transitions of neutral hydrogen in the low-density, high-redshift intergalactic medium (IGM). It is a biased continuous tracer of the quasi-linear matter density field, and the auto (cross) correlation function of the forests (with quasars) has been used to detect the Baryon Acoustic...
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Corentin Ravoux06/05/2022 10:00
The Lyman-alpha (Lya) forest is a unique probe of large-scale matter fluctuations at high redshift (z>2). In this presentation, I will show how to obtain 3D maps of the matter distribution from Lya data using tomographic reconstruction methods. This field was pioneered by deep, small-field observations. Here, I will present the largest tomographic map of matter fluctuations at z>2 over the...
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Natalie Hogg (IPhT CEA-Saclay)06/05/2022 10:15
The Etherington reciprocity theorem, or distance duality relation (DDR), describes the relationship between luminosity and angular diameter distances in pseudo-Riemannian spacetimes where photons are massless and photon number is conserved. In this talk, I will show the first joint constraints on H0 and the DDR with percentage accuracy obtained with late-time data, and use this result to...
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Eric Jullo (LAM)06/05/2022 13:30
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ALAIN BLANCHARD (IRAP , OMP)06/05/2022 14:00
The $\Lambda$CDM model has successfully passed the confrontation to many observations of cosmological relevances in the past. In recent years, several tensions have been raised up with the increasing accuracy of cosmological data. The amplitude of the matter fluctuations is regarded as one of these serious concerns. We show that redshift space dstorsion from present day surveys provide...
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Renan Isquierdo Boschetti (CPPM)06/05/2022 14:20
Voids are one of the building blocks of large scale structure (LSS) that have been capturing the attention of the community in the last decade. The reasons are that they are, in principle, easy to model, found in low density regions, mitigating much of the complications from non-linearities, present higher densities of dark energy and neutrinos than an average environment in LSS and last but...
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Emma Aycoberry06/05/2022 14:40
The Ultraviolet Near-Infrared Optical Northern Survey (UNIONS) is an ongoing deep photometric multi-band survey of the Northern sky. As part of UNIONS, the Canada-France Imaging Survey (CFIS) provides r-band data which we use to study weak-lensing peak counts for cosmological inference.
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In this talk I will explain how I assess systematic effects for weak-lensing peak counts and their impact...
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