We will present measured noise spectra of horn-coupled microwave kinetic inductance detector (MKID) arrays. These detectors are tailored for next generation multi-kilo-pixel experiments that are designed to simultaneously characterize the polarization properties of both the cosmic microwave background (CMB) and Galactic dust emission. Each array element is sensitive to two polarizations and...
One of the biggest challenges for Cosmic Microwave Background (CMB) experiments comes from our detector bandpass calibration. Uncertainties in bandpass can severely limit our measurements by limiting foreground removal and spectral fitting, which is particularly important for high-$\ell$ observations like cluster science using the Sunyaev-Zeldovich (SZ) effect. Currently, CMB experiments...
Ground-based measurements of the cosmic microwave background are subjected to short-term sky noise primarily driven by poorly-mixed atmospheric water vapor. This noise causes brightness fluctuations in telescopes and limits accessible spatial scales on the sky in the absence of appropriate modulation. To better understand the observing environment and predict performance of future telescopes,...
Taurus is a mid-latitude super-pressure balloon mission to map the polarization of the cosmic microwave background (CMB) over about 70% of the sky, in four bands from 150 - 350 GHz, and with high fidelity on very large angular scales. The signal on these scales is sensitive to the timing and details of cosmic reionization by the first stars. Knowing the total optical depth of the reionized...
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 ร risque et ร impact) and has obtained the support of three institutes (IN2P3, INSU and INP). We propose to deploy a focal plane...
The millimeter part of the spectrum is one of the least explored parts of a galaxy's spectral energy distribution (SED), yet it contains emissions from three fundamentally important physical processes: the thermal emission from dust, the free-free emission from ionized gas, and the synchrotron emission from relativistic charged particles moving in the galactic magnetic field.
During my...
The NIKA2 dual-band camera at the IRAM 30-meter telescope was used to
obtain maps of the 1 mm and 2 mm dust emission in four regions of the
nearby filaments of Taurus and Perseus. These regions encompass more
than a dozen of dense cores at different stages of evolution in the
process to form stars. The NIKA2 data are combined with published maps
of the dust temperature and of optical...
Polarized dust emission is one of the major foreground contaminants in CMB data. With increasing sensitivity and resolution in new CMB experiments, we need dust models in polarization that reflect the data both at large and small angular scales. In this talk, I will present new polarized dust maps using Planck PR4 data which improve on the existing GNILC PR3 maps.
The Planck satellite maps of the polarized sky spanning frequencies from 30 to 353 GHz (i.e. 10 mm to 850 $\mu$m) had a profound impact on our understanding of both cosmology and the interstellar medium. While the submillimeter bands at 545 and 857 GHz (550 and 350 $\mu$m respectively) were not originally designed for polarimetry, the ground calibration campaign suggested a residual...
Foreground emission from the Galaxy presents a major challenge for microwave experiments aiming to detect cosmic signals. In particular, polarized Galactic emission remains a major obstacle to precise measurements of the cosmic microwave background (CMB) polarization, such as the inflationary B-mode signal. To tackle these issues, the Pan-Experiment Galactic Science Group PySM Collaboration...
The NIKA2 Cosmological Legacy Survey (N2CLS) observed the GOODS-N and COSMOS fields with the NIKA2 millimeter camera at the 30m IRAM telescope on the Sierra Nevada.
On behalf of the N2CLS team, I will present the survey and its early results. The deep GOODS-N NIKA2 maps are close to the photometric confusion limit in both the 2.0 and 1.2 millimeter bands. A total of 120 and 67 sources in...
Detecting point sources in cosmic microwave background maps is essential for characterizing extragalactic populations and addressing foreground contamination. We present the largest catalog of extragalactic sources from the Atacama Cosmology Telescope, spanning 2008-2022 at 95, 150, and 220 GHz. Using improved source detection and classification methods, we distinguish between Active Galactic...
In this talk, I introduce a semi-analytic model designed to evaluate the Cosmic Infrared Background (CIB) power spectrum across all frequency and multipole ranges. Our methodology starts from the Halo Model, in order to describe the dark matter distribution in the Universe, capturing its non-linear behavior. We further extend the Halo Model formalism to galaxies, populating dark matter halos...
We analyze measurements of the thermal Sunyaev-Zeldovich (tSZ) effect arising in the circumgalactic medium (CGM) of L* galaxies. In our analysis we use the Faerman et al. 2017 and Faerman et al. 2020 CGM models, a new power-law model (PLM), and the TNG100 simulation.
An observation by Bregman et al. 2022 Compton-y profile implies steep electron pressure slopes. Considering the possibility of...
Extracting precise cosmology from weak lensing surveys requires modelling the non-linear matter power spectrum, which is suppressed at small scales due to baryonic feedback processes. However, hydrodynamical galaxy formation simulations make widely varying predictions for the amplitude and extent of this effect. Given the recent indications from weak lensing and kinematic Sunyaev-Zelโdovich...
With the advent of current and future high-resolution CMB experiments, the kinematic Sunyaev-Zel'dovich (kSZ) effect has become a unique observational probe of the distribution of baryons and velocities in the Universe. In this work, we propose a novel binned bispectrum of the form temperature-temperature-density to extract the late-time kSZ effect from cleaned CMB maps. Unlike 'kSZ...
I will present our upcoming kSZ velocity reconstruction analysis with ACT and DESI-LS, using a novel optimal quadratic power spectrum estimator. I will also discuss foregrounds for this analysis, as well as a method to potentially improve the SNR using machine learning of the galaxy to electron density map.
One exciting application of forthcoming CMB surveys is the measurement of CMB secondary anisotropies, including the kinetic Sunyaev Zel'dovich (kSZ) effect. By combining measurement of the kSZ effect in the CMB with galaxy survey data, one can reconstruct the large-scale radial velocity field, which contains a wealth of cosmological information. This technique, known as kSZ tomography, has...
In this talk, I will summarize the latest results from ongoing kSZ tomography velocity-reconstruction programs centered at the Perimeter Institute. Highlights will include the most recent LSS ร CMB data analyses, featuring the most stringent constraints to date on primordial non-Gaussianity from scale-dependent galaxy bias in galaxy-velocity correlations. I will also introduce a new analysis...
Baryonic matter only accounts for 5% of the mass-energy density of our Universe, where the other 95% is shared between dark energy and dark matter. About half of these baryons are currently undetected, and this discrepancy between predicted and observed baryons is known as the โmissing baryonโ problem. Cosmological simulations predict that a significant fraction of the missing baryons could...
The Atacama Cosmology Telescope (ACT) was a ground-based CMB experiment in the Atacama desert in Chile that observed the millimeter sky between 2008 and 2022 at frequencies ranging from 90 GHz to 220 GHz with three detector arrays. The combination of the ~arcminute angular resolution, large footprint, and high cadence of the experiment made the instrument an excellent tool for millimeter...
Wide-area cosmic microwave background (CMB) surveys, while optimised for precision cosmology, also contain many thousands of active galactic nuclei (AGN) observed at regular cadences. The majority of these AGN are blazars with highly variable fluxes due to relativistic shocks and motions in their jets. Observing them in millimetre wavelengths (mm) with CMB telescopes fills in a portion of the...
Recent cosmic microwave background (CMB) experiments have opened the millimeter-wave (mm) regime of the electromagnetic spectrum to time-domain astrophysics. While mm observations have been conducted in the past, this is the first time that transient events have been blindly discovered in non-targeted surveys, as opposed to follow-up or pointed observations. Past mm-wave transient surveys with...
The 6m Atacama Cosmology Telescope (ACT) has been a powerful tool for studying the cosmic microwave background (CMB) and sources and transients away from the galaxy. However, its high sensitivity and wide-field imaging capabilities also make it an excellent instrument for detecting transient phenomena near the Galactic plane, where traditional surveys face challenges due to high stellar...
The next decade will be transformative for time-domain and transient astronomy, with a new generation of wide-field surveys poised to uncover a vast population of time-varying and transient astrophysical phenomena. The Simons Observatory (SO), a new cosmic microwave background (CMB) experiment, will provide high-cadence millimeter-wave observations over ~half the sky, notably delivering...
I will introduce two new methods for large-scale structure (LSS) studies in mm-wave astronomy: (1) redshift tomography and (2) map-level density reconstruction, and demonstrate them with data to probe the thermal SZ history, cosmic infrared background (CIB), and Milky Way dust.
For the first method, I will focus on a new CIB tomography result in Chiang+2025, where we deproject 11 sky...
Line intensity mapping (LIM) is an emerging technique in observational cosmology to spatially and spectrally map the aggregate line emission from large-scale structures, which promises to offer invaluable insights into physical processes that govern galaxy formation and evolution in the cosmological context. The mm-wave sky has been and will be surveyed by a number of LIM experiments such as...
Line intensity mapping (LIM) of molecular lines such as CO and [CII] is emerging as a powerful technique for probing cosmic structure and astrophysical processes, spanning multiple wavelengths but particularly impactful in the mm regime. These tracers provide key insights into galaxy formation, the interstellar medium, and cosmic star formation across a wide range of redshifts, complementing...
