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2
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IPhT Joint Journal C…
IPhT Joint Journal Club
March 2, 2023 10:00 AM - 11:30 AM
Kepler Room
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Euclid OU-LE3 WL mee…
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4
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DAp seminar
DAp seminar
March 7, 2023 10:00 AM - 11:00 AM
Salle Galilée
Stefano Camera (Università degli Studi di Torino)
The dark Universe (TBC)
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Remote group meeting
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8
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9
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Journal Club
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Learning slot
Learning slot
March 9, 2023 11:00 AM - 12:00 PM
Kepler Room
Tutorial: Galaxy clustering theory (part II) by Filippo Vernizzi
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10
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11
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13
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CosmoStat UNIONS cos…
CosmoStat UNIONS cosmology meeting
March 13, 2023 10:00 AM - 11:00 AM
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14
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DAp seminar
DAp seminar
March 14, 2023 10:00 AM - 11:00 AM
Salle Galilée
Marie Guéguen (Université de Rennes)
Cosmology : a tension within code comparisons
Abstract: Code comparisons in cosmology are often performed with the underlying objective of identifying predictions upon which different codes converge that can be interpreted as robust, free of artifacts, predictions. Such an objective assumes that code comparisons can be constructed in such a way that the two notions of convergence and of robustness collapse. But, in order to achieve such a goal, code comparisons of structure formation have to meet an important epistemic challenge: that of constructing their codes ensemble on the basis of codes that are as independent as possible, but also comparable. In this talk, I show that enforcing the latter often amounts to multiplying common idealizations that hinder the achievement of the former, and thus leads to code comparisons that include many unscrutinized sources of artefacts possibly similarly distorting the predictions of the model. As a result, I argue that in context of high uncertainties where the domain of verification and validation of simulations has shrunk to code comparisons, code comparisons are better and actually very efficient as exploratory tools, both for getting insights into the physics implemented and for breaking the epistemic opacity of numerical simulations.
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Staff meeting
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15
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CosmoStat Developmen…
CosmoStat Development Meeting
March 15, 2023 10:00 AM - 11:00 AM
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16
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Journal Club by PIER…
Journal Club by PIERRE Marguerite
March 16, 2023 10:00 AM - 11:00 AM
Kepler Room
Marguerite Pierre will give a presentation of the various characterizations of an astronomical survey in a general way: flux limit, completeness limit, sky coverage, selection function, etc., and how they impact cosmological analysis.
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Euclid OU-LE3 WL mee…
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21
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DAp seminar
DAp seminar
March 21, 2023 10:00 AM - 11:00 AM
Salle Galilée
Francisca Kemper (ICREA, Espagne)
The interstellar dust reservoir in galaxies
Abstract: The evolution of interstellar dust reservoirs, and the evolution of galaxies themselves go hand-in-hand, as the presence of dust alters evolutionary drivers, such as the interstellar radiation field and the star formation history, while at the same time, the dust is being formed and altered by processes taking place in galaxies. However, far-infrared and submillimeter studies have revealed enormous dust masses at high redshifts that are difficult to explain with dust production from evolved stars (the so-called "dust budget problem"), while in the nearby universe there is also a significant mismatch between the dust production rate and the dust mass observed in the interstellar medium of galaxies. I will go over some possible explanations in an attempt to find a way forward towards a solution to this seeming discrepancy.
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Remote group meeting
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22
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CosmoStat Developmen…
CosmoStat Development Meeting
March 22, 2023 10:00 AM - 11:00 AM
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23
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24
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Hendrik Müller semin…
Hendrik Müller seminar
March 24, 2023 10:00 AM - 11:00 AM
Salle Cassini
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27
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CosmoStat UNIONS cos…
CosmoStat UNIONS cosmology meeting
March 27, 2023 10:00 AM - 11:00 AM
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Clement Stahl CosmoS…
Clement Stahl CosmoStat seminar
March 27, 2023 11:00 AM - 12:00 PM
Salle Kepler
Title: Exploring the effects of primordial non-Gaussianity at galactic scales
Abstract:
In this talk, I will show you my investigation of the effect of significant small-scale primordial non-Gaussianity on structure formation and the galaxy formation process. Specifically, we explored four different types of non-Gaussianities: positive and negative skeweness and kurtosis. Generically, we find a distinct and potentially detectable feature in the matter power spectrum around the non-linear scale. The feature might have interesting consequences for the S8 tension. We then show in particular that a positively skewed distribution with fNL of the order of 1000 at these scales, implies that typical galaxy-sized halos reach half of their present-day mass at an earlier stage. Building up galaxies earlier is highly relevant in the light the young massive galaxies observed by JWST. These galaxies have a quieter merging history at z < 3 than in the Gaussian case and their environment between 0.5 and 4 virial radii at z = 0 is less dense than in the Gaussian case. This quieter history and less dense environment has potentially interesting consequences in terms of the formation of bulges and bars. Moreover, we show that the two most massive subhalos around their host tend to display an interesting anti-correlation of velocities, indicative of kinematic coherence. Finally, all feedback prescriptions being otherwise identical, simulations with a negative (positive) fNL on small scales, display a slightly more (less) disky kinematics than in the Gaussian case. All these hints will need to be statistically confirmed in larger-box simulations with scale-dependent non-Gaussian initial conditions, followed by hydrodynamical zoom-in simulations to explore the detailed consequences of small-scale non-Gaussianities on galaxy formation.
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28
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DAp seminar
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Staff meeting
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29
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CosmoStat Developmen…
CosmoStat Development Meeting
March 29, 2023 10:00 AM - 11:00 AM
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GPU half day
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