With the 3rd generation camera on the South Pole Telescope, SPT-3G, over 10K square degrees of the southern sky has been surveyed in Stokes I/Q/U at frequencies of 90,150, and 220 GHz with noise levels in coadded intensity ranging from 2 to 9 $\mu$K-arcmin at roughly arcminute resolution. This provides insights over the full range in cosmic time, from the early universe to nearby objects....
The sixth public data release (DR6) of the Atacama Cosmology Telescope includes observations in total intensity and linear polarization taken between 2017 and 2022 in three frequency bands—98, 150 and 220 GHz—covering 19,000 square degrees. With white noise levels three times lower than those of Planck, the arcminute-resolution observations provide strong constraints on the physics governing...
Cosmic Microwave Background (CMB) measurements and other observations, combined with relatively basic theory, allow us to extrapolate back to when our Universe had a temperature $>10^{12}$ Kelvin, and to infer the very particular set of conditions which pertained at that time - almost uniform plasma with adiabatic, Gaussian, scale-free perturbations. The leading hypothesis for how those...
We present measurements of large-scale cosmic microwave background (CMB) E-mode polarization from the Cosmology Large Angular Scale Surveyor (CLASS) 90 GHz data. Using 115 det-yr of observations collected through 2024 with a variable-delay polarization modulator, we achieved a polarization sensitivity of $78\,\mathrm{\mu K\,arcmin}$, comparable to Planck at similar frequencies. We demonstrate...
The Simons Observatory (SO) is a cosmic microwave background (CMB) experiment situated on the Chajnantor Plateau in Chile's Atacama Desert. The observatory comprises seven mm-wave telescopes operating across six frequency bands (30-280 GHz). Six 60cm Small Aperture Telescopes (SATs) focus on detecting primordial B-mode polarization signatures of cosmic inflation in two deep,...
SPIDER is a powerful balloon-borne instrument designed to map the polarization of the millimeter-wave sky from above the bulk of the Earth’s obscuring atmosphere. SPIDER leverages the pristine observing conditions and long flight time provided by the NASA Long-Duration Balloon (LDB) platform to produce deep maps over a large area (~10% of the sky) and broad frequency range (95, 150, 280 GHz)....
The accuracy of the interpretation of the current generation of late-time cosmology probes is greatly limited by the theorists' ability to predict the response of baryons. This will only get more difficult in the coming years with the upcoming surveys (DESI-BGS, Euclid, LSST, 4-most, Simons) mapping our sky with unprecedented precision.
In this talk, I will discuss some of the efforts towards...
Exascale computing is driving a new era of cosmological simulations, enabling unprecedented precision in modeling large-scale structure formation and its interplay with the CMB. One example is the Frontier Exascale Simulation, which evolves 4 trillion particles within a 4.6 Gpc box, capturing the detailed growth of structure across cosmic time. These simulations provide high-fidelity...
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...
In Λ Cold Dark Matter (ΛCDM) cosmology, galaxy clusters form via the hierarchical merging/accretion of formerly separate Dark Matter halo systems containing cold and collisionless DM. Due to the non-turbulent nature of CDM, we would expect the most massive and brightest cluster galaxy (BCG) to come to rest at the gravitational center of the cluster’s DM halo. To test this prediction, we looked...
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...
Galaxy clusters are powerful probes used to constrain the cosmology of our universe. However, they are peppered with several systematic biases such as projection effects. Of them, the orientation of triaxial clusters with respect to the line-of-sight is expected to be one of the prime sources of scatter and potential bias in optical observables (i.e., richness and weak-lensing signal) of...
Galaxy cluster formation is driven by a variety of complicated physical processes that affect their growth and evolution through cosmic time. As a result, the matter distribution within the cluster, and therefore, its shape, can be a probe of these astrophysical processes and cosmology. Clusters grow through the accretion of new material, typically along two or three main filaments, giving...
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,...
We present a joint approach to studying galaxy clusters that combines X-ray data from the Chandra X-ray Observatory with millimeter data from both the South Pole Telescope (SPT) and the Planck satellite, leveraging the complementary capabilities of these three instruments. In particular, we exploited the high angular resolution of Chandra and SPT to map the innermost region of the cluster and...
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 à risque et à impact) and has obtained the support of three institutes (IN2P3, INSU and INP). We propose to deploy a focal plane...
Galaxy cluster mergers are rich sources of information to test both cluster astrophysics and cosmology. However, cluster mergers produce complex projected signals that are difficult to interpret from individual observational probes. Multi-probe constraints on both the gas and dark matter cluster components are necessary to infer merger parameters that are otherwise degenerate. We have...
I will present high-resolution millimeter images of dust and gas in high-redshift dusty star-forming galaxies (DSFGs). SPT0418-47 ($z \approx$ 4.22) and SPT2147-50 ($z \approx 3.76$) are two of the most well-studied gravitationally lensed, high-redshift DSFGs selected by the South Pole Telescope. Using Atacama Large Millimeter/submillimeter Array (ALMA) observations of these galaxies, I create...
The BICEP3 telescope is a 95GHz CMB polarimeter located at the South Pole searching for inflationary gravitational waves. Directly measuring non-idealities in polarization between detector pairs and across the focal plane is useful for understanding how our constraints on r are impacted by E-to-B leakage. Further, measuring polarization angles in an absolute reference frame makes telescopes...
The kinetic Sunyaev-Zel'dovich effect (kSZ) and patchy screening effect are two complementary cosmic microwave background (CMB) probes of the reionization era. The kSZ effect is a relatively strong signal, but is difficult to disentangle from other sources of temperature anisotropy, whereas patchy screening is weaker but can be reconstructed using the cleaner polarization channel. Here, we...
As they travel through the Universe, a small fraction of cosmic microwave background (CMB) photons scatter off free electrons from the gaseous halos of moving galaxies leaving a temperature signal: the kinematic Sunyaev-Zel'dovich effect (kSZ). In this work, we precisely measure this effect with velocity stacking to infer gas profiles around galaxies and their dependence on galaxy properties,...
For years, pairs of clusters have been studied in a wide range of frequencies to try to detect filaments of matter between them using. X-ray emission, the Sunyaev-Zel'dovich (SZ) effect and radio emission have all been used. Such studies are closely connected to the ‘missing baryon’ problem, an open issue in modern cosmology: the quantity of baryonic matter observed in the local Universe is...
Cold fronts in galaxy clusters, seen as sharp discontinuities in X-ray surface brightness and temperature, offer crucial insights into the physical processes shaping the intracluster medium (ICM). These structures not only trace a cluster’s dynamical history but also serve as natural laboratories for studying transport processes such as thermal conduction. In this talk, we investigate the...
Filaments connecting galaxy clusters appear to contain the vast majority of the ‘missing baryons’ in the form of a warm-hot intergalactic medium (WHIM) gas and are expected to emit a diffuse soft X-ray signal. Utilizing eROSITA’s sensitivity in the soft X-ray band, down to 0.2 keV, along with its wide field of view, raster scanning, and stable background, we are able to characterize this...
As CMB telescopes—such as the current and upcoming BICEP/Keck instruments and the future CMB‐S4 experiment—strive to measure primordial B-modes via precise polarimetry, rigorous characterization of optical materials under cryogenic conditions is increasingly critical. For instance, losses in transmissive optics elevate photon noise, degrading mapping speed and overall sensitivity. Meeting the...
In this work, I use simulations from The 300 Project to connect morphological measures and statistics of the stellar light distribution with physical processes in cluster formation. Specifically, I investigate systematic changes in the stellar density map distribution due to mechanisms such as merger and accretion histories of the galaxy clusters. The results of this investigation can then be...
Component separation is critical in CMB data analysis to clean foregrounds from CMB. The deep convolutional neural networks (CNN) have been increasingly useful in image segmentation problems of various fields to reconstruct the signal. I have built a hybrid CNN architecture in wavelet space (specifically in Needlet space ) to separate foregrounds from CMB that works in multi-resolution...
Halo core tracking is a novel concept designed to efficiently follow halo substructure in large simulations. We have recently developed this concept in gravity-only simulations to investigate the galaxy-halo connection in the context of empirical and semi-analytic models. Here, we incorporate information from hydrodynamics simulations, with an emphasis on establishing a connection between...
Most of the instruments currently observing at mm wavelenghts are located in the Southern Hemisphere. Those few in the Northern Hemisphere are mostly focused on observations of large scale CMB anisotropies with small aperture telescopes (e.g. AliCMB, GroundBIRD). Therefore, there is a gap for an instrument with a large mirror ($D\geq10\,$m) that would survey the Northern sky.
We propose a...
Cross-correlation/stacking analyses of Sunyaev-Zeldovich observations and galaxy surveys offer a promising method for studying properties of the gas reservoirs surrounding galaxies and the astrophysics that govern their evolution. These statistical studies can be used to constrain models and simulations through a detailed forward model, but the implementation and systematics of constructing a...
The Millimeter Sardinia radio Telescope Receiver based on Array of Lumped elements kids is (MISTRAL) is a novel high resolution, wide field of view millimeter camera currently installed at the Sardinia Radio Telescope (SRT), a 64 m fully steerable gregorian radio telescope located in Italy. MISTRAL was developed in the framework of the SRT-HighFreq project, funded by a National Operational...
Galaxy cluster scaling relations are fundamental for understanding cluster physics and testing ΛCDM, but their use in cosmology is still limited by large uncertainties. Many studies rely on hydrostatic equilibrium, despite numerous out-of-equilibrium systems, and the classification of cluster dynamical states remains incomplete, particularly for intermediate evolutionary stages. Even...
Galaxy clusters are powerful probes of the large-scale structure of the universe and cosmology, with their population statistics being highly dependent on the expansion history of the universe and growth of structure. In the last few decades, galaxy cluster samples across wavelengths have exceeded thousands of objects, including those identified in the millimeter regime through the use of the...
We present an open source Python package to compare simulation-based inference (SBI) approaches to MCMC inference in the context of galaxy cluster mass estimates from gravitational weak lensing data. The package, CLSBIWeakLens, provides a modular framework to flexibly run numerical experiments on cluster mass estimation from radial profiles, a typical data vector in optical cluster cosmology...
State-of-the-art cosmic microwave background (CMB) telescopes must deploy receivers with a high density of superconducting detectors. Reading out these detectors while maintaining cryogenic conditions requires novel multiplexing schemes. Microwave superconducting quantum interference device multiplexing has been shown to achieve multiplexing factors on the order of 1,000, which is a drastic...
The Simons Observatory (SO) consists of one large aperture and three small aperture telescopes currently operating in four frequency bands between 90-280 GHz, located at ∼5,200m altitude in the Atacama Desert of Chile. SO is dedicated to observing the polarized cosmic microwave background (CMB), among other science goals, with the primary focus of the small aperture telescopes (SATs) being to...
Spatially and spectrally resolved observations of the thermal and kinematic Sunyaev-Zel’dovich (SZ) effect towards galaxy clusters are crucial for understanding their formation and assembly history. Current instrumentation for direct observations of the SZ effect in the mm/submm rely either on coherent receivers or on imaging cameras. Coherent receivers can achieve a high spectral resolution,...
We present a weak lensing analysis pipeline developed for SuperBIT, a balloon-borne telescope that operates at ~36 km altitude, above 97-99% of the Earth’s atmosphere. SuperBIT completed its first science flight in 2023, delivering high-quality imaging at a fraction of space-mission costs. The pipeline involves stacking 300-second exposures, extracting sources, modeling the PSF, measuring...
The Atacama Cosmology Telescope (ACT) conducted an arcmin resolution survey of the southern sky at millimetre wavelengths from 2008-2022. In this talk I will present an update on the ACT search for galaxy clusters using the redshift independent Sunyaev-Zel'dovich (SZ) effect, using data from the full ACT survey, covering 15,000 square degrees. The final ACT Data Release 6 (DR6) cluster catalog...
The South Pole Telescope (SPT) is a 10-meter millimeter-wavelength telescope located at the geographic South Pole, one of the world’s premier sites for millimeter-wave observations. The SPT has been used to conduct several generations of wide-field high resolution cosmic microwave background (CMB) surveys including the 2500-square-degree SPT-SZ survey, the SPTpol 500d and ECS surveys, and the...
The abundance of galaxy clusters, the clustering of galaxies, and weak gravitational lensing are key observables of the cosmic large-scale structure. Over the past decade, tremendous progress was made in obtaining high-precision measurements, notably thanks to sensitive wide-field surveys of the cosmic microwave background and of galaxies and gravitational lensing. The abundance of clusters...
Galaxy clusters, representing the peaks in the cosmic density field, serve as an independent and powerful tool for investigating the evolution of cosmic structures. The strategic identification of these clusters through multi-wavelength surveys is essential for advancing our understanding of gravitational theory, general relativity, and cosmological models. A significant milestone was achieved...
The large-scale structure of the universe can be probed by different observables. Galaxy clustering, weak gravitational lensing, galaxy cluster abundances, and cluster clustering are each sensitive to different aspects of cosmic structure formation and are affected by different astrophysical and observational uncertainties. Consistency of different observables presents a strong test of our...
The Euclid mission is designed to map the geometry and growth of structure in the Universe with unprecedented precision. As part of this effort, galaxy clusters serve as a crucial probe for constraining cosmological parameters, thanks to their sensitivity to both the expansion history and the growth of cosmic structures.
In preparation for the exploitation of Euclid’s cluster samples,...
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...
Clusters of galaxies, formed at the latest stages of structure formation, are unique cosmological probes to study the formation and evolution of large-scale structures. 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 millimeter wavelength via the thermal Sunyaev-Zeldovich...
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...
The multi-component matched filer (MCMF) cluster confirmation framework, designed to leverage the synergies between ICM-selected cluster surveys and optical imaging surveys, has been applied to some of the largest and high-quality surveys to date with a focus on high purity and well controlled cluster samples for cosmological purposes. MCMF confirmed cluster catalogs have subsequently been...
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...
We present a catalog of 500 galaxy cluster candidates in the SPT-Deep field: a 100 square-degree field that combines data from the SPT-3G and SPTpol surveys to reach noise levels of 3.0, 2.2, and 9.0 uK-arcmin at 95, 150, and 220 GHz, respectively. This is comparable to noise levels expected for the wide field survey of CMB-S4, a next-generation CMB experiment. Candidates are selected via the...
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...
Galaxy clusters are the largest gravitationally bound objects in the Universe, serving as powerful cosmological probes on the growth of structure on the largest physical scales. The thermal Sunyaev-Zeld'dovich (tSZ) effect is now a well-established technique for probing the intracluster medium (ICM) of galaxy clusters on these scales. Measuring the gas pressure serves as a robust tracer of...
In a self-similar paradigm of structure formation, the thermal pressure of the hot intra-cluster gas follows a universal distribution independent of the mass scale. Thus, this thermal pressure distribution is universal in every cluster once normalised to the proper mass and redshift dependencies. The reconstruction of such a universal pressure profile requires an individual estimate of the...
As we enter a golden age of data-driven cosmology, multi-wavelength surveys are set to revolutionize our understanding of the universe. Ongoing and upcoming observations - ranging from Sunyaev-Zel'dovich (SZ) effects to X-ray emissions, fast radio bursts (FRBs), and absorption line studies — promise unprecedented insights into the astrophysical processes driving galaxy formation and evolution,...
The Three Hundred Simulation Suites include 324 re-simulated regions identified around massive clusters and resimulated with different hydrodynamical codes and resolution. Their purpose is to provide a large catalogue of theoretically modelled galaxy clusters for cosmological and astrophysical applications. Extensive work has been done to create mocks images to compare with observations and...
Including millimeter-wave (mm-wave) data in multi-wavelength studies of the variability of active galactic nuclei (AGN) can provide insights into AGN physics that are not easily accessible at other wavelengths. We will discuss the potential of cosmic microwave background (CMB) telescopes to provide long-term, high-cadence mm-wave AGN monitoring over large fractions of sky. The South Pole...
I will review what we know about mm-wave selected dusty galaxies: their composition, redshift distribution, and spectral properties. I will review the latest observations from ALMA and JWST. I will present an overview of current and planned blank-field surveys. I will discuss prospects for characterizing the population with future facilities in the coming decades.
The South Pole Telescope (SPT) is at the frontier of measuring the cosmic microwave background and surveying the millimeter sky. The third-generation SPT camera (SPT-3G) has observing frequencies centered at 90, 150, and 220 GHz (3.3, 2, and 1.4 mm) and arcminute resolution, enabling the study of millimeter-bright astrophysical objects. In this work, we present the static, emissive point...
Abstract: Information about the late-time Universe is imprinted on the small-scale CMB as photons travel to us from the surface of last scattering. Several processes are at play and small-scale fluctuations are very rich and non-Gaussian in nature. I will review some recent and exciting results that use the Sunyaev-Zel'dovich (SZ) effects and gravitational lensing to paint a full picture of...
As cosmic microwave background photons travel through the Universe a small fraction of them interact with the intervening cosmic gas and thereby imprint the properties of this gas on our CMB observations. In this talk I will describe how data from the Atacama Cosmology Telescope can be used to isolate the signals arising from hot gas throughout the Universe and how the data can be used to...
One of the most powerful tests of our cosmological model and of new physics is to determine the growth of large-scale structure with time. Motivated by this and by reports of tensions in structure growth, in the first part of my talk I will show state-of-the-art determinations of cosmic structure growth using CMB gravitational lensing measurements from the Atacama Cosmology Telescope (ACT), in...
The South Pole Telescope (SPT), a 10-meter telescope optimized for observing the primary and secondary anisotropies of the cosmic microwave background (CMB), is currently equipped with the SPT-3G camera. The high angular resolution and low noise maps produced by SPT-3G are ideally suited for reconstructing the CMB lensing potential, mapping matter distribution to high redshifts, and probing...
The kinetic Sunyaev--Zel'dovich kSZ effect is sourced by CMB photons scattering off of moving electron gas, and contains information on gas density as well as velocity. Through the velocity dependence, this signal contains information about cosmology on the largest scales. By combining a CMB map with a galaxy survey to measure where the electrons are, the velocity information can be isolated...
Mapping the distribution of baryonic mass in our Universe down to the group-sized halo masses it is essential to clarify how much baryonic matter is locked up in halos and in filaments. Non-gravitational processes affect the thermodynamical conditions of the hot gas and baryonic content of groups and clusters of galaxies, causing deviations from the theoretical self-similar expectations....
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...
Optically identified galaxy clusters have the potential to provide some of the most precise cosmological constraints, as they enable the detection of lower-mass clusters. However, they are also highly susceptible to systematic effects, with projection effects being a major challenge. This misidentification of member galaxies introduces anisotropies in the observed distribution of optical...
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 study the robustness of a simulation-based inference (SBI) method in the context of cosmological parameter estimation from galaxy cluster abundance in mock cluster datasets. I will describe an application where we train an SBI model, based on a mixture density network (MDN), to derive posteriors for cosmological parameters from a stacked cluster data vector constructed using an analytic...
Galaxy cluster abundance measurements serve as a powerful probe for constraining cosmological parameters such as the matter density ($\Omega_m$) and the amplitude of density fluctuations ($\sigma_8$). Wide-area surveys detect clusters using observables like the thermal Sunyaev-Zeldovich (SZ) effect, a spectral distortion in the Cosmic Microwave Background (CMB). Accurate cosmological...
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-Zel’dovich...
Galaxy clusters serve as powerful cosmological probes through number count analysis. Beyond that, the gas distribution in cluster outskirts provides a model-independent method for deriving competitive cosmological constraints. By combining HIGHMz—a subsample of 32 of the most massive CHEX-MATE clusters—with X-COP clusters, this study derives robust and precise constraints on the matter density...
Independent constraints on the Hubble constant ($H_0$) from local distance ladders and early Universe CMB data can be derived from cluster sizes by combining X-ray and millimetre observations of the intracluster medium. Using XMM-Newton and Planck data, we present the inference on $H_0$ by studying systematic mismatches, $\eta_T$, between X-ray and millimetre temperature (or pressure)...
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...
Modern multi-platform, multi-band millimeter-wavelength surveys of the sky with arcminute resolution are designed to explore the origin and evolution of the universe. The next generation of CMB experiments, including the Simons Observatory (SO), will address a wide range of pressing scientific questions with unprecedented sensitivity. Among these, one of the primary targets is the faint...
MISTRAL is a new facility instrument open to the scientific community that will help investigate the ’missing baryon’ problem, as well as many other scientific cases from extragalactic astrophysics to solar system science. The MIllimeter Sardinia radio Telescope Receiver based on Array of Lumped elements KIDs (MISTRAL) is a cryogenic W-band LEKID camera which has been mounted at the Gregorian...
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.
The TolTEC camera is a trichroic polarimeter deployed on the 50-meter Large Millimeter Telescope (LMT) on Sierra Negra in Mexico. It observes in three photometric bands 150, 220, and 280 GHz with respective angular resolutions of 10, 6, and 5 arcseconds. TolTEC achieved first light in 2022 and commenced commissioning in December of that year. Issues with the LMT and TolTEC prevented...
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 × 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...
OLIMPO is a concept for a balloon-borne instrument to map the thermal and kinematic SZE at high signal-to-noise in a sample of nearby galaxy clusters and connecting bridges. In combination with X-ray data primarily from eROSITA and radio observations from SKA Pathfinders, OLIMPO will provide precise constraints on the turbulent and coherent velocities within the ICM due to structure growth...
The Next-generation Extended Wavelength-MUltiband Sub/millimeter Inductance Camera (NEW-MUSIC) on the Leighton Chajnantor Telescope (LCT) will be a first-of-its-kind, six-band, trans-mil-li-me-ter-wave (``trans-mm'') polarimeter covering 2.4 octaves of spectral bandwidth to open a new window on the trans-mm time-domain frontier, in particular new frontiers in energy, density, time, and...
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 “missing baryon” problem. Cosmological simulations predict that a significant fraction of the missing baryons could...
Primary anisotropies and gravitational lensing of the cosmic microwave background (CMB) provide a wealth of information on cosmology. In an analysis that extracts such information, a first step is to create sky maps of anisotropies in the I, Q, and U Stokes parameters of millimeter-wave radiation fields. We will present the procedure that we used to make and validate new sky maps of the...
SPT-3G, the third-generation camera on the South Pole Telescope (SPT-3G), is being used to observe the cosmic microwave background (CMB) anisotropies to unprecedented depth at arcminute resolution. The temperature and E-mode polarization anisotropies of the CMB provide a wealth of information on the composition and evolution of the universe. This talk presents the upgraded cosmological...
I will present power spectra of the cosmic microwave background (CMB) anisotropy in temperature and polarization, as measured from the Atacama Cosmology Telescope (ACT) Data Release 6 maps. These maps cover 19,000 square degrees in bands centered at 98, 150, and 220 GHz, with white noise levels three times lower than Planck in polarization, and angular resolution roughly five times higher. I...
Cosmic birefringence is a hypothetical signature of parity violation in the electromagnetic interaction, and would manifest as a rotation of CMB polarisation as the signal travels through our Universe. This effect is degenerate with instrument polarisation, making it a calibration and data analysis challenge to constrain. In this talk, I will focus on the sensitivity to cosmic birefringence of...
The Cluster HEritage project with XMM-Newton - Mass Assembly and Thermodynamics at the Endpoint of structure formation (CHEX-MATE) is a three-mega-second Multi-Year Heritage Programme to obtain X-ray observations of a minimally-biased, signal-to-noise-limited sample of 118 galaxy clusters detected by Planck through the Sunyaev–Zeldovich effect. The programme aims to study the ultimate products...
The NIKA2 camera operating at the IRAM 30-m telescope has unique performance for the resolved observation of the Sunyaev-Zel’dovich effect towards galaxy clusters. As part of the NIKA2 guaranteed-time, the SZ Large Program (LPSZ) is devoted to the high-angular resolution SZ mapping of a representative sample of SZ-selected clusters, at intermediate to high redshift, drawn from the catalogues...
We present the latest development of "Baryon Pasting", a novel framework that adopts a physics-based approach for forward-modeling SZ and X-ray observations of galaxy clusters and groups. Baryon Pasting enables efficient exploration of the vast astrophysical and cosmological parameter space required for current and upcoming millimeter-wave surveys, such as the Simons Observatory and CMB-S4,...
Post-processing techniques emulating baryonic physics in gravity-only simulations are a cornerstone of modern cosmology. In particular, predicting the thermodynamic properties of the intracluster gas is necessary to exploit these simulations for galaxy cluster cosmology in the millimeter-wave and X-ray domains. In this talk, I will introduce picasso, a model to predict thermodynamic properties...
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...
In Sunyaev-Zeldovich (SZ) cluster cosmology, accurately determining cluster masses is crucial for constraining cosmological parameters through cluster number counts.
As the mass is not an observable, a scaling relation is needed to link cluster masses to the integrated Compton parameter Y, i.e., the SZ observable, to exploit data from large millimeter surveys. Current cosmological results use...
Understanding the scaling relations between galaxy cluster properties (such as mass, luminosity, richness, and luminosity) is crucial for unraveling the physical processes shaping them. However, these relations are highly sensitive to uncertainties in sample selection functions, requiring assumptions about the abundance and properties of unobserved populations. The potential impact of...
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...
We present our analysis of the factors that impact the reconstruction of density profiles in galaxy clusters, which are a fundamental tool for studying the properties of the intra-cluster medium and a key ingredient for measuring the total mass radial profiles under the assumption of hydrostatic equilibrium.
We used a sample of 105 galaxy clusters drawn from cosmological simulations...
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...
Galaxy clusters form through the accretion of smaller structures, with mergers of subclumps and the sloshing of cold gas in higher-entropy environments affecting their intracluster medium (ICM) distribution. These processes leave observable imprints, such as edges, shocks, cold fronts, and discontinuities in surface brightness, as well as variations in integrated quantities.
In this study,...
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...
Line intensity mapping has emerged as a promising method of probing large-scale structure and star formation over cosmic time. At mm wavelengths there are a number of lines including [CII] and CO which are being targeted by current and upcoming experiments. Measuring [CII] in the 200-300 GHz range will allow us to probe the Epoch of Reionization, while the measurement of CO in these wavelength...
The Shirokoff Line-Intensity Mapper (SPT-SLIM) is a mm-wavelength, superconducting on-chip spectrometer observing redshifted CO in the 2mm atmospheric window using the 10-meter South Pole Telescope (SPT). The instrument was recently deployed for the first time during the 2024-2025 austral summer season at South Pole, where it conducted a short two-week observing campaign. We will present an...
Line Intensity Mapping, LIM, is an emerging observational technique that measures the integrated emission from galaxies as fluctuations in a 3D cosmic volume. By doing so, it aims to fill a key gap in studies of cosmology and galaxy formation – LIM data cubes are sensitive to the emission from all galaxies in a population, even the very faintest. LIM experiments can thus study the evolution of...
Observing the sky at millimeter wavelengths offers a powerful window into the history of our Universe. In this lecture we’ll explore how these observations help uncover clues about the Universe’s first moments and provide insights into its ultimate fate. A Q&A with the audience will follow the talk.
I will talk about reconstructing the non-linear matter power spectrum $P(k)$ using a joint analysis of gravitational lensing of the cosmic microwave background (CMB) and lensing of galaxies. This reconstruction is motivated by the $S_8$ tension between early-universe CMB predictions and late-time observables. We use CMB lensing data from the Atacama Cosmology Telescope DR6 and cosmic shear...
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...
Precision measurements of the cosmic microwave background’s gravitational lensing provide a uniquely powerful window into the distribution of dark matter, offering insights into neutrinos, dark energy, and enabling powerful consistency tests of the standard cosmological model.
In this talk, I will describe ongoing efforts in producing state-of-the-art CMB lensing maps from the final...
The weak gravitational lensing of the cosmic microwave background photons due to the line-of-sight matter distribution is a powerfully precise probe of cosmology. One of the key insights that this phenomenon known as CMB lensing unveils is an unbiased mapping of dark matter and its characteristics, allowing us to trace the formation and growth of large-scale structure over vast cosmic epochs....
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...
There is no consensus on how baryonic feedback shapes the non-linear matter power spectrum from hydrodynamical simulations. With improvements in survey size and methodology, this uncertainty is now a limiting systematic for cosmic shear inference at small scales. Modern simulations are tuned to reproduce a variety of galaxy observations, however, they still predict a wide range of feedback...
The hot circumgalactic medium (CGM) is believed to host most of the baryons and metals that are missing from the stellar disk and ISM. However, detecting the hot CGM is extremely challenging due to its faintness and the complexity of the background in mm and X-ray. We have cross-correlated the WISExSuperCosMos galaxy catalog with the Compton-y map derived from the CMB data of the Atacama...
For decades, instruments operating in the X-ray and mm wavebands have provided the capability of observing the hot intracluster medium (ICM) of galaxy clusters, and determining its density, temperature, and pressure. It has been possible only in recent years to determine the spatially resolved kinematic properties of the cluster gas via measurements of line shifting and broadening in the...
The ALMA Wideband Sensitivity Upgrade (WSU) is an ongoing partnership-wide initiative that will dramatically increase the ALMA system’s observing efficiency across ALMA’s entire wavelength range and for all observing modes. As part of the WSU, most of the observatory’s hardware elements will be replaced or upgraded, including key receivers and signal chain components; a new correlator, the...
The CCAT Observatory's Fred Young Submillimeter Telescope, a novel, high-throughput, 6-meter aperture telescope, is currently under construction at 5600 m on Cerro Chajnantor in the Chilean Atacama Desert. CCAT will address a suite of science goals, including Big Bang cosmology, star formation, line-intensity mapping of cosmic reionization, galactic magnetic fields, astronomical transients,...
CMB-S4, the next-generation ground-based cosmic microwave background (CMB) experiment, will make measurements with unprecedented precision and provide fundamental new insights into physics and astronomy. Its key measurements will include the search for primordial gravitational waves, probes of the nature of dark matter and dark energy, mapping matter throughout the Universe, and the detection...
AtLAST is a next-generation concept for a 50-m single dish telescope covering 30-950 GHz in frequency and featuring a field of view >500 times larger than that of current large mm-wave facilities like the Large Millimeter Telescope. When it is built, it will be the first submm single dish with >20-m aperture ever and the only >12-m single dish with full access to the southern sky. AtLAST will...
Accurate characterization of galaxy clusters in millimetre-wavelength surveys requires rigorous separation of the thermal Sunyaev-Zeldovich (tSZ) distortion of the CMB signal from its contaminants. This task should ideally disentangle extended components, such as Galactic dust, Cosmic Microwave, and sub-millimetre backgrounds, whose spectral shapes and spatial distributions exhibit specific...
In this talk I will discuss the planned daily public release of monitored source light curves and transient alerts from the (Advanced) Simons Observatory provided by daily survey-scale observations in the millimeter. The scan strategy for the Large Aperture Telescope (LAT) is designed to cover a high fraction of the survey volume once every few days, providing excellent coverage of...
To understand the evolution of dust properties in molecular clouds in the course of the star formation process, we constrain the changes in the dust emissivity index from star-forming filaments to prestellar and protostellar cores to T Tauri stars. Using the NIKA2 continuum camera on the IRAM 30 m telescope as part of the GASTON large program, we observed the B211/B2I3 filament in Taurus at...
Future photometric and spectroscopic surveys will reveal unprecedented details about faint galaxies in massive clusters, requiring high-resolution theoretical models. Full-physics hydrodynamical simulations accurately reproduce galaxy properties but are computationally expensive, particularly for resolving low-mass galaxies in dense environments. In this work, we present an emulator based on...
Distant quasars (QSOs) are considered key actors in the evolution of the early Universe. High-redshift merging systems, containing two or more supermassive black holes surrounded by close companions, tidal bridges, and tails on kiloparsec scales, represent an expected phenomenon, as evidenced by the first spatially resolved spectroscopic observations from the James Webb Space Telescope (JWST)....
In our previous work, we estimated the masses of galaxy clusters from the PSZ2 full-sky sample using deep learning methods (arXiv:2209.10333). Our approach involved generating a simulated training dataset that closely replicated PSZ2 observations, accounting for instrumental effects such as noise and the point spread function (PSF). However, certain factors,...
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.
In this talk, I will introduce the Resolved Cluster Evolution Sunyaev-Zeldovich Survey (ReCESS): a 200-hour-plus observing campaign aimed at resolving the intracluster medium (ICM) through the thermal Sunyaev-Zeldovich (tSZ) effect in 25 ACT-selected galaxy clusters within a redshift range of $1.2 < z < 2$ using MUSTANG-2 on the GBT and ALMA. I will present the first results on the average...
