Colloque national CMB-France #8

Liste des Contributions

24. From Cryogenic Detector Readout Chains to a CMB Observatory - Potential Contributions

Damien PRELE (APC)

24/11/2026 14:00

Sessions 1

Cryogenic detection and readout chains for future CMB observatories are far from off-the-shelf products. Their development requires years of coordinated work on detectors, superconducting devices, readout electronics, cryogenic integration and characterisation. These developments must remain closely aligned with the scientific objectives of each experiment, as detector performance, instrument...

30. Development of flexible superconducting ribbon cables for CMB observation instrumentation

Xavier de la Broïse (CEA/DRF/IRFU)

24/11/2026 14:20

Sessions 1

We initiated the development of flexible superconducting ribbon cables, originally intended for the CMB-S4 observatory, to interconnect detectors with the first stage of the electronics. These cables needed to be produced in very large quantities while meeting specific performance requirements. To mitigate risks, we carried out this development in partnership with three different industrial or...

12. CreSZendo: From Clusters to REionization via the SZ Effect with Northern high-resolution Deep Observations

Juan-Francisco Macias-Perez (LPSC)

24/11/2026 14:40

Sessions 1

The CreSZendo proposes conducting the largest and deepest high-resolution (10” at 260 GHz) millimetre survey of the sky, focusing on measuring the Sunyaev-Zeldovich (SZ) effect. Thanks to our team's state-of-the-art Kinetic Inductance Detector (KID) technology, we will construct and install a four-band millimetre wavelength camera at the IRAM 30 m telescope. This camera will have an...

22. SNO-CMB

Guilaine Lagache (LAM), Marian Douspis (IAS)

24/11/2026 15:00

Sessions 1

Discussion sur la création d'un Service National d'Observation autour des activités CMB.

39. The Simons Observatory: Commissioning of the Mid-Frequency Small Aperture Telescopes

24/11/2026 16:00

Sessions 2

15. The Simons Observatory Large Aperture Telescope: Cosmology with high resolution data of the Cosmic Microwave Background and preliminary Science Verification results

Karen Perez Sarmiento (Institut d'Astrophysique Spatiale)

24/11/2026 16:30

Sessions 2

The Simons Observatory (SO) Large Aperture Telescope (LAT) achieved first light in February 2025 and is expected to reach unprecedented depth at high resolutions over a large area of the millimeter sky for the duration of the survey, making it one of the leading Cosmic Microwave Background (CMB) experiments of the next decade. In this talk, I will provide an overview of the LAT science goals,...

5. The Simons Observatory: A framework for efficient map-based simulations to mitigate instrumental systematics for CMB surveys

Magdy Morshed (INFN Ferrara)

24/11/2026 16:50

Sessions 2

The current and future observations of the CMB are expected to reach unprecedented sensitivity to place stringent constraints on both cosmological parameters and fundamental physics. The ground-based Simons Observatory Large Aperture Telescope started observations last year, and will provide the most sensitive small-scale CMB measurements. A tight control over instrumental systematics is...

16. The Simons Observatory: Initial Science Observations with the Small Aperture Telescopes

Ema Tsang

24/11/2026 17:10

Sessions 2

In this talk, we tentatively present the first results from the initial science observations, including polarisation maps and power spectra. We describe the analysis pipelines, from data preprocessing to the component separation strategy used to handle Galactic foregrounds, and discuss the main instrumental systematics and their mitigation.

25. Latest news from SPT-3G and SPO

Silvia Galli

24/11/2026 17:30

Sessions 2

The 10m South Pole Telescope (SPT) maps the CMB sky with arc-minute resolution. With its high sensitivity observations at 95, 150 and 220GHz its third generation camera (SPT-3G) aims at providing unprecedented constraints on the cosmological parameters, hopefully soon to be based on the analyses of 10% of the CMB sky.
The South Pole Observatory combines the SPT observations with those of the...

6. Extracting cosmology and astrophysics from the cross-correlation between the thermal Sunyaev-Zeldovich signal and galaxy clustering

Léa Dumilly (Institut d'Astrophysique Spatiale)

24/11/2026 17:50

Sessions 2

The cosmic microwave background (CMB) traces the matter distribution through the imprints left by its interactions with large-scale structure. Together, the CMB and large-scale structure probes provide complementary insights into the matter distribution at different epochs of the Universe. Their distinct theoretical modeling and observational systematics make cross-correlations...

2. Atmosphere mitigation in CMB observations

Jacques Delabrouille (IN2P3)

25/11/2026 09:00

Sessions 3

I will present atmocube, a new package for fast and accurate simulation of atmospheric emission and absorption impacting CMB observations from ground-based observatories, and the potential use of co-pointing observations with a multi-channel lidar to characterize and potentially disentangle atmospheric contamination in CMB data streams with dedicated multi-instrument data-analysis techniques.

4. Time-Domain Component Separation for Atmospheric Emission Removal in CMB Observations

Dr Benjamin Beringue (APC, CNRS)

25/11/2026 09:20

Sessions 3

Ground-based observations of the cosmic microwave background (CMB) are severely challenged by atmospheric emission, which outshines the faint astrophysical and CMB signals. In particular, fluctuations in atmospheric water vapour introduce non-stationary, spatially complex correlations in the time-ordered data (TOD), coupling neighbouring detectors and contaminating large angular scale modes in...

9. Atmosphere mitigation in CMB observations using multi-frequency time-domain component separation

Julien Tang (Université Paris Cité)

25/11/2026 09:40

Sessions 3

CMB observations from ground-based observatories are limited in sensitivity by the fluctuating emission from the Earth's atmosphere, mostly due to water vapor inhomogeneities. Standard mitigation techniques either remove a significant fraction of the cosmological signal (low-frequency filtering) or leave residuals from instrumental imperfections and polarized atmospheric emission...

32. DESI: DR2 Results and Perspectives

Christophe Yeche (CEA Irfu/SPP)

25/11/2026 10:30

Sessions 4

The Dark Energy Spectroscopic Instrument (DESI) is building the largest 3D map of our universe to measure its expansion history over the past 11 billion years, and thereby, study dark energy. Over a five-year period (Run 1a), DESI has spectroscopically classified nearly 40 million galaxies and quasars over 1/3 of the sky and to redshifts z < 3.5.

The DESI collaboration has completed...

17. Euclid meets CMB lensing: first cosmological constraints from the Euclid Quick Data Release

Dr Margherita Lembo (Institut d'Astrophysique de Paris (IAP))

25/11/2026 11:00

Sessions 4

The Euclid Quick Data Release (Q1) offers the first opportunity to test the cosmological potential of Euclid on real data. In this talk I will present the first cosmological analysis performed on Euclid data, based on the tomographic clustering of photometric galaxies in the three Euclid Deep Fields and their cross-correlation with CMB lensing from Planck and ACT. Despite covering only about...

18. Generalised map-based component separation method to probe isotropic cosmic birefringence and its application to cross-experiments calibration

Malcolm Landais (Laboratoire Astroparticule & Cosmology)

25/11/2026 11:20

Sessions 4

In this presentation, I will introduce a generalized map-based component-separation framework that accounts for instrumental polarization angle miscalibrations and propagates calibration prior information into cosmological parameter inference.
This framework is being developed as an extension of the Megatop pipeline, a code designed to probe primordial B modes in the context of the Simons...

19. Look-elsewhere effect in searches for new physics with the CMB

Merry DUPARC (IJCLab)

25/11/2026 11:40

Sessions 4

ΛCDM fits CMB data remarkably well, and new physics is usually searched for by adding one parameter at a time: curvature, N_eff, dark-energy equation of state, varying constants, and others. Several have shown 2 to 3σ hints in Planck data. But when many extensions are tested on the same data, some such deviations are expected from noise alone: this is the look-elsewhere effect. Because the...

40. Accessing and using Jean Zay and Dalia for CMB computations

Stéphane Ilic (IDRIS)

25/11/2026 12:00

Sessions 4

CMB analyses are increasingly computationally demanding: high-resolution map-making, component separation, large ensembles of time-ordered-data and sky simulations, and high-dimensional likelihood and simulation-based inference all push against local resources, and machine-learning methods (emulation of pipelines, fast likelihoods, delensing, foreground modelling) add a further GPU-intensive...

26. LiteBIRD Status

Ludovic Montier (IRAP)

25/11/2026 14:00

Sessions 5

I will present the current status of the LiteBIRD JAXA mission, after it recently passed the Mission Definition Review at JAXA and it entered into project phase. A new exciting phase has just started, with a new instrumental design and enhanced science goals I will describe in more details.

37. FOSSIL

25/11/2026 14:30

Sessions 5

33. CMB-probe

Jacques Delabrouille

25/11/2026 15:00

Sessions 5

The 2020 decadal survey in Astronomy and Astrophysics in the US (released in 2021) proposed a program of ground and space-based activities and recommended critical actions to carry-out its identified most compelling science goals. It stated that to address the major science questions identified by the Panel on Cosmology, the cosmic microwave background remains the single most important...

8. COSMOCal project: a calibrator for CMB experiments

Alessia RITACCO (CNRS-LPSC)

25/11/2026 15:20

Sessions 5

Precise measurements of the Cosmic Microwave Background (CMB) polarization anisotropies are essential for probing fundamental physics, particularly through the search for primordial B-modes generated by inflationary gravitational waves and the investigation of cosmic birefringence, a potential signature of physics beyond the Standard Model. Achieving the required accuracy demands unprecedented...

13. Impact of Galactic dust complexity on calibration of future CMB space missions

Silvia Micheli

25/11/2026 15:40

Sessions 5

The search for primordial gravitational waves imprinted in the polarization of the Cosmic Microwave Background (CMB) is a major scientific goal of next-generation CMB experiments. Achieving the sensitivity required to detect primordial B-modes demands precise control of instrumental systematics and a robust separation of the cosmological signal from astrophysical foregrounds. In particular,...

21. BISOU: a balloon mission for CMB spectral distortions

Xavier COULON (IAS)

25/11/2026 16:30

Sessions 6

BISOU (Balloon Interferometer for Spectral Observations of the primordial Universe) is a CNES balloon-borne spectrometer designed to measure CMB spectral distortions. Its primary goal is the first detection of the CMB y-distortion monopole signal arising from the gravitation heating of gas during large-scale structure formation. BISOU should also measure the CIB and extragalactic CO monopoles,...

23. Systematics in CMB spectral distortions spectrometers: From Instrument Model to Laboratory Breadboard

Morgane LOQUET LE GALL (IAS)

25/11/2026 16:50

Sessions 6

CMB (Cosmic Microwave Background) spectral distortions can probe the thermal and energetic history of the early Universe. However, the CMB spectrum has not been remeasured since COBE/FIRAS, which constrained deviations from a blackbody to ΔI/I ≲ 10⁻⁵. Detecting these faint signals requires anticipating, from the earliest design stages, how instrumental systematics will limit the...

20. A reference more perfect than the CMB: the thermal challenge of FOSSIL

Dr Valentin SAUVAGE (Institut d'Astrophysique Spatiale)

25/11/2026 17:10

Sessions 6

The cosmic microwave background (CMB) spectrum measured by COBE-FIRAS is the most perfect blackbody observed so far, with upper limits on spectral distortions of |y| < 1.5×10⁻⁵ and |μ| < 9×10⁻⁵. Smaller distortions, left by energy injection at different epochs of cosmic history, are nevertheless expected below these limits. FOSSIL, a CMB spectral distortion mission proposed to ESA M8, aims to...

3. Map-based asymmetric beam convolution

Dr Artem Basyrov (APC, CNRS)

25/11/2026 17:30

Sessions 6

We present a new method to convolve any real beam represented as a 2D array with a sky map $m$. A joint pointing -- beam operator allows to faithfully and fully recreate the beam convolved signal with a beam of any shape including asymmetric beams. This technique is useful for simulations of observations produced by asymmetric realistic beams, and estimating $T \rightarrow P$ and $E...

11. Exact map-space beam convolution via spin-mapmaking

Camille Demay (University of Trento, University of Ferrara)

25/11/2026 17:50

Sessions 6

We present a map-based method for exact beam convolution using spin-mapmaking, enabling efficient propagation of non-ideal beam systematics to the map level. Validated against TOD-level 4π convolution for circular, elliptical, and Planck HFI scanning beams, it is exact to numerical precision in the limit where subpixel effects are neglected.

7. High angular resolution maps of polarized dust emission using scattering transforms on Planck data.

Alexandros Tsouros (ENS-PSL)

26/11/2026 09:00

Sessions 7

Accurate statistical characterization of Galactic foregrounds is crucial for extracting cosmological information from CMB polarization data. However, the complexity of the interstellar medium leads to non-Gaussian structures that cannot be fully captured by traditional summary statistics, like the power spectrum. On the other hand, simulation and machine-learning approaches, while informative,...

14. Self-supervised framework for component separation in the submillimeter sky

Victor Bonjean (LPENS)

26/11/2026 09:20

Sessions 7

We present a self-supervised framework to simultaneously reconstruct the different components of the submillimeter sky. The framework offers flexibility in the choice of emission models, including nonlinear models with spatially varying spectral parameters, such as the spectral index β in dust-emission models. Instrumental effects and constraints can also be incorporated into the...

10. Extragalactic CO as a CMB foreground: an analytic halo model for the CO auto-spectrum and its correlation with the CIB

Giorgia Zagatti (University of Ferrara)

26/11/2026 09:40

Sessions 7

Rotational lines of carbon monoxide (CO) emitted by star-forming galaxies are redshifted into the frequency bands of CMB experiments. Because these bands are broad, many transitions emitted over a wide redshift range add up to a continuum-like signal that is strongly correlated with the cosmic infrared background (CIB). Current predictions of this foreground rely mostly on simulations. I will...

1. Towards cross-correlations between the CMB and the 21cm signal

Adélie Gorce (IAS, Université Paris-Saclay)

26/11/2026 10:00

Sessions 7

Because they probe two different, complementary aspects of the same question of cosmic reionisation (where is the neutral gas for one, and where are the free electrons for the other), the high-redshift 21cm signal and CMB secondary anisotropies such as the kSZ and Thomson screening are highly complementary. Their cross-correlation has been shown in many works to be a promising observable for...

29. Galactic Science with the LiteBIRD satellite: Spectral characterization of diffuse Galactic polarized emission at the angular power spectrum level

Samy Vinzl (IRAP)

26/11/2026 11:00

Sessions 8

Accurate modeling of polarized Galactic emission has become a major challenge for current and next-generation Cosmic Microwave Background (CMB) B-mode experiments. Ignoring the spectral complexity of thermal dust and Galactic synchrotron emission when integrating along the line of sight and over large sky fractions inevitably leads to biases in CMB polarization analyses.
In this talk, I will...

27. Bayesian inference of polarised dust SED variations with scattering transforms: validation on Planck-like simulations

Sébastien Pierre (LPENS)

26/11/2026 11:20

Sessions 8

Spatial variations of the polarized dust spectral energy distribution (SED) are a major concern for the search for primordial Cosmic Microwave Background (CMB) $B$-modes, as they could be misinterpreted as a cosmological signal. These variations are however difficult to characterize, since only a few noisy polarized channels trace dust in currently available surveys. For this purpose, we...

28. Non-parametric spectral-matching component separation for measuring CMB B-mode polarization with a satellite mission

Hoang Viet Tran (APC, Université Paris Cité)

26/11/2026 11:40

Sessions 8

The measurement of primordial CMB B-mode polarization is fundamentally limited by our ability to separate this faint signal from bright and complex Galactic foregrounds. Spectral Matching Independent Component Analysis (SMICA) offers a flexible, semi-blind approach to this foreground-cleaning problem. However, its standard implementation relies on a physically unrealistic assumption of...