I will present the status of the LiteBIRD JAXA mission, after it entered in reformation period since September 2025.
This talk will highlight the LiteBIRD space mission's capability to map the thermal Sunyaev-Zeldovich (SZ) effect, arising from the scattering of CMB photons by hot baryonic gas within and around galaxy clusters. Although primarily designed to search for large-scale CMB B-mode polarization, LiteBIRD will deliver full-sky maps in total intensity with unprecedented sensitivity across 15...
Future satellite missions focusing on the tensor-to-scalar ratio r will likely include a rotating half-wave plate (HWP) device in order to precisely recover the B-mode polarization signal. Patanchon [2023] modeled the effect of HWP systematic imperfections leading to Intensity to Polarization (IP) leakage on the measurement of the B-mode signal. This model is now implemented in the LiteBIRD...
Not long after the Planck space mission launch, it appeared that signals from the detectors operated at 100 mK of one of its instruments, HFI, were affected by cosmic rays. The heat dissipation in the detectors due to these particles hits created spurious signals appearing as glitches in the data. Further post-launch studies have allowed for most of these glitches to be removed.
Several space...
Taurus is a balloon-borne CMB experiment, planning to launch in 2027. It will fly from Wanaka, New Zealand, as the payload of a NASA Super Pressure Balloon in the stratosphere of the Southern Hemisphere, giving it a view of more than half of the sky. By imaging at night for several weeks with its three refractor telescopes, Taurus will map the polarized microwave emission of the sky in four...
We will discuss non-Gaussian effects in CMB lensing maximum a posteriori methods (MAP) coming from the large-scale structure bispectrum and extragalactic foregrounds emission. We will show how MAP methods naturally mitigate biases that are relevant for standard CMB lensing estimators, both in auto and cross-correlation analyses. This will not be relevant only for CMB-S4, for which MAP methods...
Gravitational lensing of the Cosmic Microwave Background (CMB) will soon be reconstructed with unprecedented precision, driven by deep polarisation maps from upcoming experiments like SPT-3G, the Simons Observatory, and CMB-S4. Reconstructing and subtracting the lensed B modes of polarisation is crucial to uncover the primordial B modes from inflation. In this talk, I will introduce an optimal...
The discrepancy between local measurements of the Hubble constant and inferences from CMB and galaxy clustering data, known as the "Hubble tension", has motivated numerous models introducing additional components active before recombination. While many such models have been proposed, none are currently strongly favoured by data. This highlights the critical role of upcoming CMB experiments,...
The Simons Observatory is an ensemble of telescopes being progressively deployed on Cerro Toco (Chile), aiming at measuring both small and large angular scales of the cosmic microwave background. Three Small Aperture Telescopes have been successfully installed on site and started operating from late 2023. These half-meter mirrors telescopes are designed to measure the large-scale polarization...
Over the past year, the proposal to build a high-frequency Small Aperture Telescope (SAT) to add to the Simons observatory has gradually become more and more consolidated. This project named Kairos is currently submitted for funding to the RI2 CNRS program (Recherche à risque et à impact) and has obtained the support of three institutes (IN2P3, INSU and INP). We propose to deploy a focal plane...
Rayleigh scattering of the Cosmic Microwave Background (CMB) is a less studied yet potentially powerful probe of the recombination history. Scattering of CMB photons off neutral species right after recombination presents a distinctive $\nu^4$ scaling with frequency as well as a strong correlation with the primary CMB. These unique features should facilitate its detection by the next generation...
The quest for primordial B-mode polarisation in the cosmic microwave background poses significant analysis challenges. Because the signal is so faint, robust measurements (or constraints) require a particular attention to systematic effects, astrophysical foregrounds, as well as the interplay between the two. This task is made even more difficult by the volume and complexity of the datasets...
Component separation is the crucial and challenging analysis step to estimate the CMB signal in the presence of astrophysical contaminants.
The Galactic dust and synchrotron are the primary millimeter emissions to remove in the search for primordial CMB B-modes.
One major unknown is the full complexity of the polarized astrophysical foreground spectral properties, which is yet to be assessed...
In the context of future experiments measuring the polarization of the Cosmic Microwave Background (CMB), COSMOCal proposes a method independent of laboratory calibration of CMB instruments and cosmological model assumptions to calibrate next-generation millimeter-wave telescopes. The primary objective is to achieve polarization angle calibration with a precision better than 0.1 degrees. This...
The ambitious quest to detect the faint B-modes of CMB polarization, pursued by projects like the Simons Observatory (SO) and LiteBIRD, requires rigorous control over systematic effects in polarimetry. The PolarKID project, supported by CNES (2023–2025), is dedicated to testing LEKIDs in a filled array configuration to demonstrate their capability for precise polarization detection. This setup...
SPT-3G, the third-generation camera on the South Pole Telescope, observes cosmic microwave background (CMB) anisotropies with arcminute resolution and 4.5muKarcmin coadded noise in temperature. Recent analyses of polarization data from the 2019 and 2020 seasons have yielded the most precise reconstruction of the E-mode spectrum above ell = 2000 and the CMB lensing spectrum above L = 350. From...
The detection of primordial tensor modes, i.e. gravitational waves, through primordial CMB B-modes is considered the smoking gun signal for inflation. However, in order to solidify this conclusion, we need to insure that other primordial mechanisms do not produce the same signal. To that end, primordial gravitational vector modes (V-modes) and their sourcing of primordial magnetic fields...
Clusters of galaxies, formed at the latest stages of structure formation, constitute unique cosmological probes and are sensitive to cosmological parameters related to structure formation like the rms of matter fluctuations. With the advent of large CMB surveys like those from the Planck satellite, the ACT and SPT telescopes, we now have access to large catalogs of galaxy clusters detected at...
I will introduce the CCAT collaboration which has built the Fred Young Submillimeter Telescope (FYST, pronounced feast). I’ll provide an overview of the first generation instruments being deployed on FYST and their science goals. I’ll conclude with a discussion of the state of the CCAT collaboration and our timelines.
The Epoch of Reionisation imprints its history and morphology on the Cosmic Microwave Background temperature and polarisation anisotropies through two effects: The kinetic Sunyaev Zel'dovich (kSZ) effect and Thomson scattering. I present an analytical approach to derive consistently the angular power spectra of the three main resulting imprints that are the spatial fluctuations of the Thomson...
Historically disregarded as a foreground contaminant, the kinetic Sunyaev-Zel'dovich (kSZ) effect has seen a surge of interest in recent years as an additional cosmological probe. Arising from interactions between CMB photons and free electrons in ionised bubbles, the kSZ signal contains information about the timeline and morphology of Reionisation, a critical, yet poorly understood, period...
CMB-S4 is conceived by a broad community as the path forward to realizing the enormous potential of CMB measurements for understanding the origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. The most efficient strategy to reach these science goals is to combine two complementary sky surveys: an ultra-deep...
