Colloque national CMB-France #2

15 nov. 2021, 09:30 → 16 nov. 2021, 17:00 Europe/Paris

Cette initiative vise à mettre en place une animation scientifique au niveau national autour des études CMB. Ce workshop fait suite au premier qui a eu lieu de 2 demi-journées les 2 et 3 juin 2021, en distanciel: CMB-France #1.

Le CMB-France #2 aura lieu les 15 et 16 Novembre 2021 à l'IAP.

 

L'inscription est gratuite mais obligatoire.

 

CMB-France peut prendre en charge les missions (dans la limite des stocks disponibles). Renseignez-vous auprès de M. Tristram.

 

L’agenda est en cours de finalisation mais l’idée de ces colloques est de:

• présenter les nouveautés scientifiques et les nouveaux résultats dans le domaine
• donner un statut sur l’avancement des expériences ou des projets en cours
• permettre aux jeunes (post-doc, PhD) de présenter leur travail

N’hésitez pas à nous contacter ou à soumettre vos propositions de presentation (avant le 1er Novembre).

 

Les informations de connexion seront envoyées par la mailing-liste cmb-france. Pensez à vous inscrire.

 

  Cette action est soutenue par le PNCG.

lundi 15 novembre

09:30 → 10:00 Welcome CMB-France #2

10:00 → 11:20 Contributions

10:00 Prédictions de performances de l'analyse combinée Euclid et CMB

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 levier important et améliorer considérablement les contraintes sur notre modèle cosmologique, en particulier sur ses extensions non-standardes. Dans cet exposé, je présenterai les prédictions validées de performance des futures contraintes de corrélation croisée Euclid x CMB, effectuées par le groupe de travail scientifique "CMB-cross correlations". Ces résultats ont abouti à la rédaction d'un article officielle de la collaboration Euclid, accepté pour publication.

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Forecasting the joint analysis of Euclid and CMB experiments

Through weak lensing and galaxy clustering measurements, Euclid will provide unprecedented constraints on the late Universe. On the other hand, high-quality CMB observations (Planck and future CMB experiments) can -- and already do -- put tight constraints on the early Universe. Combining these two sources of cosmological information can yield a significant lever arm and improve tremendously the constraints on our cosmological model, especially its non-standard extensions. In this talk, I will present the validated forecasts of the future Euclid x CMB cross-correlation constraints, performed by the CMB-cross correlations Science Working Group. These results culminated in the writing of an official Euclid Collaboration paper, accepted for publication.

Orateur: Dr Stéphane Ilic (Observatoire de Paris - LERMA)

Ilic_CMB_France_2.pdf

10:20 Cosmological constraint with new Planck tSZ map

The thermal Sunyaev-Zeldovich (tSZ) effect is produced by the inverse Compton scattering of cosmic microwave background (CMB) photons by hot electrons, particularly in galaxies clusters. It has been used as a powerful tool to constrain the cosmological parameters given its particular sensitivity to sigma8 and omega_m.

I produced a new all-sky tSZ map constructed from the latest Planck PR4 data released in 2020 with the MILCA algorithm. It exhibits ~7% less noise and less survey strips than the one produced by the Planck collaboration in 2015. I will present the result of the cosmological analysis with this new tSZ map.

Orateur: Hideki Tanimura (Institut d'Astrophysique Spatiale)

cmb-france-upload.pdf

10:40 Cosmology with the kinetic Sunyaev-Zeldovich effect: Independent of the optical depth and sigma 8

The cosmological constraints from the kinetic Sunyaev-Zeldovich experiments are degenerate with the optical depth measurement, which is commonly known as the optical-depth degeneracy. In this talk, we introduce a new statistic based on the first moment of relative velocity between pairs in a triplet, which is capable of constraining cosmological parameters independent of the optical depth, and $\sigma_8$. Using 22,000 $N$-body simulations from the Quijote suite, we quantify the information content in the new statistic using Fisher matrix forecast. We find that it is able to obtain strong constraints on the cosmological parameters, particularly on the summed neutrino mass. The constraints have a factor of 6.2-12.9, and 2.3-5.7 improvement on all cosmological model parameters when compared to those obtained from the mean pairwise velocity, and the redshift-space halo power spectrum, respectively. Thus the new statistic paves a way forward to constrain cosmological parameters independent of the optical depth and $\sigma_8$ using data from future kinetic Sunyaev-Zeldovich experiments alone.

Orateur: Joseph Kuruvilla (IAS)

cmb-france-21.pdf

11:00 The Simons Observatory and a new framework for constraining cosmic birefringence in the presence of systematics and galactic foregrounds

The Simons Observatory (SO) is a new generation CMB experiment. It is currently under construction in the Atacama desert in Chile and its first light is planned in 2022. It gathers 60,000$TES detectors on two types of telescopes: 3 Small Aperture Telescopes (SATs) and one Large Aperture Telescope (LAT). This hybrid observatory was shown to be the most efficient approach to study the early and late Universe. 5 years of observations with the SATs will give constraints on the primordial gravitational waves with a precision on the tensor-to-scalar ratio of sigma(r)~0.003. To reach these scientific goals, galactic emissions such as dust and synchrotron polarized radiation are a major issue. The SATs and the LAT observe in 6 frequency bands from 27GHz to 280GHz, so that SO will be able to characterize and remove the galactic foregrounds. Systematic effects such as the polarisation angle of our telescope also need to be taken into account. However the conventional self-calibration method deletes possible non zero CMB EB power spectrum which renders impossible any detection of cosmic birefringence. In this talk I will present a new method which aims at constraining both r and the birefringence angle using foreground cleaned and polarisation angle corrected CMB maps in the context of SO.

Orateur: Baptiste Jost

Jost_CMB_France.pdf

11:30 → 12:30 CMB news

11:30 le futur de CMB-France: vers un GDR cosmologie ?

GDR-CMB.pdf

14:00 → 18:00 CMB Spectroscopie

14:00 Distortions Spectrales (théorie)

Orateur: Cyril Pitrou

SpectralDistortions.pdf

14:45 PIXIE

Orateur: Nabila Aghanim

15:10 BISOU: a balloon project to measure the CMB spectral distortions

The BISOU (Balloon Interferometer for Spectral Observations of the Universe) project aims to study the viability and prospects of a balloon-borne spectrometer, pathfinder of a future space mission dedicated to the measurements of the CMB spectral distortions, in order to achieve a first measurement. A balloon concept based on a Fourier Transform Spectrometer, covering a spectral range from about 90 GHz to 2 THz, adapted from previous mission proposals such as PIXIE and PRISTINE, is being studied and modelled. Taking into account the specificities of a balloon flight in term of requirements and conditions (i.e. residual atmosphere, observation strategy for instance), this CNES phase 0 study will evaluate if such an spectrometer is sensitive enough to measure at least the Compton y-distortion while consolidating the instrumental concept and improving the readiness of some of its key sub-systems.

Orateur: Bruno Maffei (IAS)

BISOU_CMB-F_2.pdf

15:30 Options for an L-class microwave spectroscopy space mission

Following on the submission of four coordinated white papers in answer to the ESA "Voyage 2050" consultation of the scientific community, CMB spectral distortions has been identified as one of possible science themes for a future L-class space mission to be launched in the 2035-2050 time frame. I will summarize the science cases, observation requirements, and possible mission profiles in this context.

Orateur: Jacques Delabrouille (IN2P3)

Microwave-Spectroscopy-Mission-compressed.pdf

15:50 café

16:20 Sensitivity modeling to CMB spectral distortions

In the context of future missions and instruments dedicated to CMB spectrum measurements, a code modeling sky signals including various emissions (CMB, foregrounds, spectral distortions) has been adapted from previous ones. Combined with a generic spectrometer instrument model in development, preliminary sensitivity estimates and forecasts of the potential spectral distortion observables will be presented.

Orateur: Xavier Coulon (IAS)

CMB_F_V2.pdf

16:40 Forecasts on small-scale primordial non-Gaussianity through cross-correlations between CMB and μ-distortion anisotropies

Multi-field inflation models predict sizeable non-Gaussian primordial perturbations and consequently anisotropic $\mu$-type spectral distortions of the cosmic microwave background (CMB) blackbody. While CMB anisotropies allow us to probe primordial non-Gaussianity at wavenumbers $k \simeq 0.05\,{\rm Mpc}^{−1}$, $\mu$-distortion anisotropies are related to non-Gaussianity of primordial perturbation modes with much larger wavenumbers, $k ≃ 740\, {\rm Mpc}^{-1}$. Through cross-correlations between CMB anisotropies and $\mu$-distortion anisotropies, one can therefore shed light on the aforementioned inflation models. We will discuss the capabilities of a future CMB satellite imager like LiteBIRD to measure $\mu T$ and $\mu E$ cross-power spectra between anisotropic $\mu$-distortions and CMB temperature and E-mode polarization anisotropies in the presence of foregrounds, and present LiteBIRD forecasts on $f_{\rm NL}^\mu(k \simeq 740\, {\rm Mpc}^{−1})$. We will show that $\mu E$ cross-correlations with CMB polarization actually provide more constraining power on $f_{\rm NL}^\mu$ than $\mu T$ cross-correlations in the presence of foregrounds, and that the joint combination of $\mu T$ and $\mu E$ observables adds further leverage to the detection of small-scale primordial non-Gaussianity with future CMB imagers.

Orateur: Dr Mathieu Remazeilles (University of Manchester)

Remazeilles_cmb_france.pdf

17:00 Spectral studies of the interstellar dust and CMB millimetre emission

We advocate R&D in spectroscopy with KIDs to tackle polarized foregrounds in the next generation CMB instruments. In particular, in order to remove the dust polarized emission, the use of low resolution spectrocopy may be required. I will present Grenoble efforts towards that goal.

Orateur: Dr Francois-Xavier Désert (IPAG)

SpectralStudies_CMB-France_Nov2021_FXDesert.pdf

mardi 16 novembre

09:00 → 12:30 Contributions: Open session 1

09:00 First low latitudes reconstruction of the dust polarization spectral energy distribution variation

The search for primordial gravitational waves signals imprinted in the Cosmic Microwave Background (CMB) polarization B-modes signal motivates the development of a new generation of high sensitive experiments (e.g. CMB-S4, LiteBIRD), which would be able to trace a signal several orders of magnitude lower than the one in total intensity. However, insidious instrumental and foreground systematic effects could bias this detection and therefore need to be carefully addressed. Among those, the knowledge of foreground emissions appears to be crucial. In particular the galactic dust polarized emission spectral dependence, not yet fully characterized, could leave a high level of uncertainty in the cosmological polarization data and falsify the CMB B-modes detection.
The characterization of the dust spectral energy distribution (SED) variations detected in intensity in the Planck-HFI data show that it will probably be the most critical issue in the quest of primordial B-modes.
In this work we present a cross correlation analysis, performed by using the last Sroll2 release of Planck polarization data, showing evidence of a dust SED variation at low galactic latitudes. The dependence of this variation by possibly different effects will be discussed.

Orateur: Alessia Ritacco

CMB-France_A.Ritacco.pdf

09:20 Statistical separation of dust and CIB with Wavelet Phase Harmonics

Modelling the emission of Galactic dust is a main challenge for CMB polarization experiments. Current models based on Planck data suffer from the difficulty of separating dust emission from the Cosmic Infrared Background (CIB). We will show that the two components may be statistically separated using their radically different structure on the sky. Our approach uses a state-of-the-art model of the CIB and the Wavelet Phase Harmonics (WPH) statistics. We will present results obtained on mock data and Herschel observations in the far infrared at high Galactic latitude.

Orateur: Constant Auclair (LPENS)

CMB_France_presentation_Auclair_LPENS.pdf

09:40 Moment expansion and the challenge of polarized dust SED complexity for B mode detections.

Characterising accurately the polarised dust emission from our Galaxy will be decisive for the quest for the Cosmic Microwave Background (CMB) primordial $B$-modes. The incomplete modelling of its potentially complex spectral properties could lead to biases in the CMB polarisation analyses and to a spurious detection of the tensor-to-scalar ratio $r$. It is particularly crucial for future surveys like the LiteBIRD satellite, which aims at constraining the faint primordial signal leftover by Inflation with an accuracy on the tensor-to-scalar ratio $r$ of the order $10^{-3}$. Variations of the dust properties along and between lines of sight lead to unavoidable distortions of the spectral energy distribution (SED) that can not be easily anticipated by standard component separation methods. This issue can be tackled using a moment expansion of the dust SED, an innovative parametrisation method imposing minimal assumptions on the sky complexity.

In a first study, we applied this formalism to the $B$-mode cross-angular power spectra computed from simulated LiteBIRD polarisation data at frequencies between 100 and 402\,GHz, containing CMB, dust and instrumental noise. The spatial variation of the dust spectral parameters (spectral index $\beta$ and temperature $T$) in our simulations, lead to significant biases on $r$ ($\sim$21\,$\sigma_{r}$) if not properly taken into account. Performing the moment expansion in $\beta$, as in previous studies, reduces the bias but do not lead to reliable enough estimates of $r$. We introduce for the first time the expansion of the cross-angular power spectra SED in both $\beta$ and $T$, showing that, at the LiteBIRD sensitivity, it is required to take into account the SED complexity due to temperature variations to prevent analysis biases on $r$. Thanks to this expansion and despite the existing correlations between some of the dust moments and the CMB signal, responsible for a rise of the error on $r$, we can measure an unbiased value of the tensor-to-scalar ratio with an uncertainty as low as $\sigma_{r}=8.8\times10^{-4}$.

Recent results including the treatment of the synchrotron component will be discussed as well as ongoing and future work exploiting this new tool for component separation.

Orateur: Léo Vacher (Institut de recherche en astrophysique et planétologie (IRAP))

moments-cmb-france2.pdf

10:00 Single frequency CMB B-mode inference with realistic foregrounds from a single training image

With a single training image and using wavelet phase harmonic augmentation, we present polarized Cosmic Microwave Back- ground (CMB) foreground marginalization in a high-dimensional likelihood-free (Bayesian) framework. We demonstrate robust foreground removal using only a single frequency of simulated data for a BICEP-like sky patch. Using Moment Networks we estimate the pixel-level posterior probability for the underlying {𝐸, 𝐵} signal and validate the statistical model with a quantile- type test using the estimated marginal posterior moments. The Moment Networks use a hierarchy of U-Net convolutional neural networks. This work validates such an approach in the most difficult limiting case: pixel-level, noise-free, highly non-Gaussian dust foregrounds with a single training image at a single frequency. For a real CMB experiment, a small number of representative sky patches would provide the training data required for full cosmological inference. These results enable robust likelihood-free, simulation-based parameter and model inference for primordial B-mode detection using observed CMB polarization data.

Orateur: Dr Niall Jeffrey (École normale supérieure)

nialljeffrey_CMBFrance2021.pdf

10:20 café

10:40 Study of beam side-lobes systematics and calibration for the LiteBIRD mission

LiteBIRD is a full sky space mission, expected to be launched in the late 2020s, whose goal is to constrain primordial physics via a high precision measurement of CMB polarization. It is a strategic Large-class mission of JAXA and is strongly supported in Europe, in particular by CNES which is in charge of the Medium and High Frequency Telescopes. LiteBIRD's main scientific objective is to find strong evidence of the cosmic inflation era through a measurement of the tensor-to-scalar ratio r from a high precision observation of CMB B-modes.
This can only be done with an extreme control of systematic effects. Among the expected sources of systematic errors, those sourced by beam far side-lobes are believed to be the most important for LiteBIRD. Indeed, they induce foreground contamination from the galactic plane to cleaner regions at high galactic latitude that ar not entirely cleaned by component separation and can have a strong impact given LiteBIRD's high sensitivity. In this talk, I will present a study of this systematic effect, and the conclusions on the calibration requirements and design of the instruments.

Orateur: Clément Leloup (APC - CNRS)

CMB-France_2021.pdf

11:00 Retrieving cosmology from small scale CMB foregrounds

Small scale CMB data contain a lot of cosmological information hidden in the different components : primordial CMB, tSZ effect, kSZ effect, CIB. Standard analyses assume templates for non primordial CMB component and lose the cosmological signature of large scale structures contained in secondary anisotropies.
I will present a new analysis of SPT data at small scales where the tSZ spectrum is derived from the halo model, or from Machine learning, and bring additional constraints. I will show the cosmological and scaling relation parameter constraints obtained by combining SPT CMB data and Planck tSZ measurements.

Orateur: Marian Douspis (IAS)

CMB_highell_CMBfrance_2021_douspis.pdf

11:20 Assessing consistency between CMB temperature and polarization measurements

CMB observations from the Planck satellite have provided cosmic variance limited temperature measurement at large and intermediate scales. In the next couple of years, ground-based experiments such as SPT, ACT and Simons Observatory will make a high resolution measurement of CMB polarization, allowing the extraction of competitive cosmological informations from $C_\ell^{EE}$ and $C_\ell^{TE}$. Physics beyond the standard model, or unmodelled instrumental systematics could introduce some inconsistencies between $T$ and $E$ measurements with respect to the $\Lambda$CDM model. In this work we apply different methods to quantify a possible scale dependent T-E inconsistency in different CMB datasets : Planck, ACTPol and SPT3G.

Orateur: Adrien La Posta (IJCLab, CNRS, France)

CMB France #2.pdf

11:40 Wide-survey of the QUIJOTE CMB experiment

QUIJOTE (Q-U-I JOint TEnerife) is an experiment that operates from the Teide Observatory (Canary islands) at microwave wavelengths (10 < ν < 40 GHz), with the aim to characterise the low frequency polarized Galactic foregrounds, and to study the polarization of the CMB. Recently the Multi Frequency Instrument (MFI) of QUIJOTE concluded a campaign of wide survey observations, providing new maps of the full northern sky at four central frequencies: at 11, 13, 17 and 19 GHz. These maps will be publicly delivered soon. In this talk I will present the QUIJOTE-MFI wide-survey maps and the scientific results related to them. In particular I will report on the characterisation of the diffuse polarized synchrotron and anomalous microwave emission (AME). I will also present new results concerning the microwave Haze, which is an excess of diffuse radiation located around the galactic center region, with spatial correspondence to the gamma-rays Fermi bubbles.

Orateur: Federica Guidi (IAP)

CMB_france_fg.pdf

12:00 The case for a high resolution all-sky millimetre survey

A dedicated 15m telescope could map the all-sky in the millimetre, adding 20 arcsecond resolution to Planck all-sky maps. We will present the scientific drivers for that instrument: CMB, lensing, SZ, Cosmic Web, CIB, and Polarized dust. This would provide a European original contribution to the S4 efforts at a moderate cost (20ME).

Orateur: Dr Francois-Xavier Désert (IPAG)

HighResAllSkymmSurvey_CMB-France_Nov2021_FXDesert.pdf

14:00 → 16:00 CMB news: CMB News #2

14:00 New Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season

The BICEP/Keck series of experiments targets the polarisation of the Cosmic Microwave Background at degree-scale resolution from the South Pole. In our most recent release, we present results from an analysis of all data taken by the BICEP2, Keck Array and BICEP3 CMB polarisation experiments up to and including the 2018 observing season. The Q/U maps now reach depths of 2.8, 2.8 and 8.8 μKcmb arcmin at 95, 150 and 220 GHz respectively, over an effective area of ≈ 600 square degrees at 95 GHz and ≈ 400 square degrees at 150 & 220 GHz. Adding publicly available maps of Planck and WMAP at frequencies from 23 to 353 GHz, our likelihood analysis yields the constraint r_{0.05} < 0.036 at 95% confidence. Running maximum likelihood search on simulations we obtain unbiased results and find that σ(r) = 0.009.
In this talk, I will give an overview of the current state and upcoming upgrades of the BICEP/Keck program, and detail our analysis pipeline from map and power spectra to constraints on cosmological parameters. I will also address how we validate our analysis choices and tackle systematic effects.

Orateur: Clara Vergès (Harvard - CfA)

BK18_CMBFrance_CVerges.pdf

15:00 Which path forward to CMB-S4 ?

CMB-S4 status and way forward...

Orateurs: François R. Bouchet (IAP), Radek Stompor (CNRS, Laboratoire Astroparticule et Cosmologie)

European CMB coordinators 10_08_21.pdf