Colloque national Action Dark Energy 2021 - 5ème édition

Liste des Contributions

1. Welcome / Accueil

Alain Blanchard (IRAP , OMP)

13/10/2021 10:10

2. Fundamental constants, gravity and dark energy

Jean-Philippe Uzan (IAP / CNRS)

13/10/2021 10:20

Invité

46. Planck constraints on the tensor-to-scalar ratio

Matthieu Tristram (IJClab, CNRS, France)

13/10/2021 11:00

Contribué

Contributions

18. Prédictions de performances de l'analyse combinée Euclid et CMB

Dr Stéphane Ilic (Observatoire de Paris - LERMA)

13/10/2021 11:30

Invité

Grâce aux mesures de lentillage gravitationnel et de clustering des galaxies, Euclid posera des contraintes sans précédent sur l'Univers récent. D'autre part, des observations CMB de haute qualité (Planck et futures expériences) sont capables d'imposer des contraintes strictes sur l'Univers primordial. La combinaison de ces deux sources d'informations cosmologiques peut constituer un bras de...

4. Dark Energy direct detection in space: MICROSCOPE and beyond

Joel Bergé (ONERA)

13/10/2021 14:30

Invité

26. Scale-dependence in DHOST inflation

Andrei Lazanu (École Normale Supérieure)

13/10/2021 15:10

Contribué

Contributions

27. Flat rotation curves, MOND-like behavior, and CMB spectrum in the Dirac-Milne universe

Gabriel Chardin (CSNSM Orsay)

13/10/2021 15:30

Contribué

Contributions

28. Mesure des fluctuations du monopole du fond diffus cosmologique

Calum Murray (LPSC)

13/10/2021 15:50

Contribué

Contributions

29. Y-a-t-il une tension avec les amas?

Alain Blanchard (IRAP , OMP)

13/10/2021 16:10

Contribué

Contributions

6. Dark Energy Survey Year 3 cosmology results

Dr Agnès FERTÉ (JPL)

13/10/2021 17:00

Invité

39. Weak lensing cluster masses and mass-richness relation in DESC DC2 simulations

Constantin Payerne (LPSC (IN2P3))

13/10/2021 17:40

Contribué

Contributions

Constraining the mass-observable relations is a key ingredient for cluster cosmology. In particular, for optical surveys such as the Rubin LSST, the cluster abundance relies on the determination of the mass-richness relation. In that context, weak gravitational lensing by galaxy clusters can be used as a powerful tool to estimate cluster masses. We use the cluster-galaxy weak lensing in the...

5. Champs scalaires et matière noire

Aurelien Hees (SYRTE - Observatoire de Paris)

14/10/2021 09:15

Invité

38. A 'variable' gravitational constant and consequence on cosmology.

Ziad Sakr (IRAP : Institut de Recherche en Astrophysique et Planétologie)

14/10/2021 09:55

Contribué

Contributions

31. The cosmological constant as a classical eigenvalue

Giovanni Manfredi (CNRS)

14/10/2021 10:10

Contribué

Contributions

45. Rotating Inflation

Kenza ZEGHARI (Université Pierre et Marie Curie, Paris 6)

14/10/2021 10:25

Contributions

We study Bianchi cosmologies coupled to a matter source that has the field theoretical description of a solid. Models
of solid inflation are known for not being very efficient in diluting away anisotropy. While confirming this fact, our study finds another potential feature of Solid inflation, namely a ``rotation” of the principal axes of the expansion.
Such a rotation is not just a ...

35. DESI Survey Validation

Christophe Yeche (CEA Irfu/SPP)

14/10/2021 10:40

Contribué

Contributions

12. On the Hubble tension and primordial magnetic fields

Dr Karsten Jedamzik (LUPM)

14/10/2021 11:30

Invité

33. (g-2) of the muon and screened modified gravity

Philippe Brax (IPHT Saclay)

14/10/2021 12:00

Contribué

Contributions

34. Dark Gravity confronted with SN, BAO and the CMB

Frederic Henry-Couannier

14/10/2021 12:15

Contribué

Contributions

7. Measurement of full-shape cosmology from the galaxy two-point clustering of DESI samples

Pauline Zarrouk (LPNHE)

14/10/2021 14:30

32. On the impact of lensing magnification on galaxy clustering analysis

Michel-Andrès Breton (Laboratoire d'Astrophysique de Marseille)

14/10/2021 15:10

Contribué

Contributions

36. Non-ideal self gravity and cosmology: a possible solution to the dark mass and energy problems within the Newtonian limit?

Pascal Tremblin (CEA Paris-Saclay)

14/10/2021 15:40

Contribué

Contributions

37. Can dark energy emerge from a varying G and spacetime geometry?

Ekim Taylan Hanimeli

14/10/2021 16:00

Contribué

Contributions

43. Glimmers of a post Geometric Perspective.

Federico Piazza (CPT, Marseille)

14/10/2021 16:15

Contribué

Contributions

Quantum gravitational effects are usually associated with the Planck scale but they could also become important at low energy if the wavefunction of the metric field fails to be peaked around a classical configuration.
I try to understand such deviations from classicality within canonical quantum gravity by introducing a "fluid of observers" in the low energy theory and defining a distance...

14. (g-2) of the muon and screened modified gravity

philippe brax (IPHT Saclay)

Contribué

The Fermilab measurement of the anomalous magnetic moment of muons seems to be at odds with the standard model of particle physics. Coupled scalar fields such as the chameleon or the symmetron, which modify gravity locally, could account for the discrepancy.

25. A 'variable' gravitational constant and consequence on cosmology.

ziad sakr (IRAP : Institut de Recherche en Astrophysique et Planétologie)

Contribué

Constraints on the cosmological concordance model parameters are usually obtained using the locally measured value of the gravitational constant G. Here we relax this assumption and determine the impact of such hypothesis on the physics involved in the prediction of the cosmological observables. Using the latest CMB temperature and polarization correlations data and distance measurements from...

30. A 'variable' gravitational constant and consequence on cosmology.

ziad sakr (IRAP : Institut de Recherche en Astrophysique et Planétologie)

Contribué

Contributions

17. Are classification metrics good proxies for science output?

Dr Emille Ishida (LPC-UCA)

Contribué

Population-level transient studies dependent on light curve classifiers often use classification performance as a proxy for metrics of the physical parameters of interest. This strategy allows a complete separation between the relatively straightforward classification stage and the more computationally intensive science analysis, meaning that design decisions for each are made independently of...

23. Can dark energy emerge from a varying G and spacetime geometry?

Ekim Taylan Hanimeli

Contribué

The accelerated expansion of the Universe implies the existence of an energy contribution known as dark energy. Associated with the cosmological constant in the standard model of cosmology, the nature of this dark energy is still unknown. In this talk I will discuss an alternative gravity model in which this dark energy contribution emerges naturally, as a result of allowing for a...

8. Contributions TBD

Contribué

13. Contributions TBD

contributions

21. Dark Gravity confronted with SN, BAO and the CMB

Dr frederic henry-couannier

Contribué

Dark Gravity is a natural extension of general relativity in presence of a flat non dynamical background. Matter and radiation fields from its dark sector,
as soon as their gravity dominates over our side fields gravity, produce a constant acceleration law of the scale factor. After a brief reminder of the Dark Gravity theory foundations, the confrontation with the main cosmological probes...

15. DESI Survey Validation

Christophe Yeche (CEA Irfu/SPP)

Contribué

DESI est un relevé spectroscopiques de 35 millions de galaxies et de quasars réalisé sur un télescope de 4m à Kitt Peak (Arizona). Le but est d'étudier les BAO et les RSD pour des redshifts de 0. à 3.5. Le projet durera 5 ans. Il vient de terminer en mai 2021 le relevé de validation et de commencer les observations du relevé principal.
L'objectif de cette présentation est de montrer les...

11. Flat rotation curves, MOND-like behavior, and CMB spectrum in the Dirac-Milne universe

Gabriel Chardin (CSNSM Orsay)

Contribué

The Dirac-Milne (D-M) universe, a symmetric matter-antimatter universe, i.e. with equal quantities of matter and antimatter, but where antimatter behaves as a negative mass component repulsing both matter and itself (see G. Manfredi et al., Phys. Rev. D 98, 023514 (2018) for a precise definition) presents several concordance properties with our universe (age, luminosity distance,...

42. Glimmers of a post Geometric Perspective.

federico piazza (CPT, Marseille)

Contribué

Contributions

Quantum gravitational effects are usually associated with the Planck scale but they could also become important at low energy if the wavefunction of the metric field fails to be peaked around a classical configuration.
I try to understand such deviations from classicality within canonical quantum gravity by introducing a "fluid of observers" in the low energy theory and defining a distance...

20. Mesure des fluctuations du monopole du fond diffus cosmologique

Calum Murray (LPSC)

Contribué

Les raies d'absorption moléculaire de quasars distants et l'effet Sunyaez-Zel'dovich thermique permettent de mesurer le monopole du fond diffus cosmologique (CMB) à différents endroits et époques de l'univers. Cette mesure permettrait notamment de contraindre les fluctuations de la densité d'énergie de radiation. Chacune de ces méthodes a des caractéristiques propres qui seront décrites dans...

10. Non-ideal self gravity and cosmology: a possible solution to the dark mass and energy problems within the Newtonian limit?

Pascal Tremblin (CEA Paris-Saclay)

Inspired by the statistical mechanics of an ensemble of interacting particles (BBGKY hierarchy), we propose to account for small-scale inhomogeneities in self-gravitating astrophysical fluids by using a non-ideal Virial theorem and non-ideal Navier-Stockes equations that involve the pair radial distribution function (similar to the correlation function), as for the interaction energy and...

16. On the impact of lensing magnification on galaxy clustering analysis

Michel-Andrès Breton (Laboratoire d'Astrophysique de Marseille)

Contribué

In this talk I will discuss about the impact of magnification bias on the determination of the growth rate from redshift-space clustering. We use a the RayGal suite of $N$-body simulations that accounts for the fully non-linear structure formation and perform realistic galaxy clustering analyses, similarly as in observations, in different regime of magnification bias. We investigate a minimal...

9. Planck constraints on the tensor-to-scalar ratio

Matthieu Tristram (IJClab, CNRS, France)

Contribué

I will present constraints on the tensor-to-scalar ratio r using Planck data as described in [Tristram et al., A&A, 647, A128 (2021)].
In this paper, we use the latest release of Planck maps (PR4), processed with the NPIPE code, which produces calibrated frequency maps in temperature and polarisation for all Planck channels from 30 GHz to 857 GHz using the same pipeline. We computed...

24. Scale-dependence in DHOST inflation

Dr Andrei Lazanu (École Normale Supérieure)

Contribué

We study the inflationary consequences of Degenerate Higher Order Scalar Tensor (DHOST) theories in a de Sitter background. We perturb the de Sitter background by operators breaking either the degeneracy condition, i.e scordatura DHOST, or the shift symmetry in the scalar field. We first consider derivative scordatura and find that in all cases the power spectra of curvature perturbations are...

3. TBD

philippe brax (IPHT Saclay)

Invité

22. The cosmological constant as a classical eigenvalue

Giovanni Manfredi (CNRS)

Contribué

We propose to recast Einstein's field equations as a nonlinear eigenvalue problem, where the cosmological constant $\Lambda$ plays the role of the (smallest) eigenvalue. This mathematical interpretation is fully worked out for a simple classical model of scalar gravity. The essential ingredient for the feasibility of this approach is that the classical field equations be nonlinear, i.e., that...

40. un GDR cosmologie?

Discussion: un GDR cosmologie?

19. Y-a-t il une tension avec les amas ?

ALAIN BLANCHARD (IRAP , OMP)

Contribué

Les mesures des fluctuations du fond diffus cosmologique (CMB) par Planck permettent de contraindre l'amplitude des fluctuations de la matière au décalage vers le rouge à $z \sim 1100$ dans le modèle $\Lambda$CDM, et donc de l'amplitude actuelle $\sigma_8$. D'autre part, l'abondance des amas Sunyaev-Zeldovich (SZ) détectés par Planck, avec des masses déduites sous l'hypothèse d'équilibre...