M. Tristram
A5106497874- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Dark Matter and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Scientific Research and Discoveries
- Superconducting and THz Device Technology
- Geophysics and Gravity Measurements
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Astrophysical Phenomena and Observations
- Relativity and Gravitational Theory
- Gamma-ray bursts and supernovae
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Particle physics theoretical and experimental studies
- Radioactive Decay and Measurement Techniques
- Statistical and numerical algorithms
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Astro and Planetary Science
- Scientific Measurement and Uncertainty Evaluation
- Advanced Differential Geometry Research
Laboratoire de Physique des 2 Infinis Irène Joliot-Curie
2020-2024
Institut National de Physique Nucléaire et de Physique des Particules
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Université Paris-Saclay
2010-2024
National Institute of Standards and Technology
2024
Campbell Collaboration
2023
Université Paris-Sud
2011-2020
GANIL
2007-2020
Japan Aerospace Exploration Agency
2020
Centre National d'Études Spatiales
2020
We present constraints on the tensor-to-scalar ratio $r$ using a combination of BICEP/Keck 2018 (BK18) and Planck PR4 data allowing us to fit for consistently with six parameters $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model. discuss sensitivity uncertainties in as defined by data. In particular, we are able derive constraint reionization optical depth $\ensuremath{\tau}$ thus propagate its uncertainty into posterior distribution $r$. While is slightly lower than current ground-based...
We present constraints on the tensor-to-scalar ratio r using Planck data. use latest release of maps (PR4), processed with NPIPE code, which produces calibrated frequency in temperature and polarization for all channels from 30 GHz to 857 same pipeline. computed BB angular power spectrum, we also discuss coming TT spectrum. Given Planck's noise level, spectrum gives that are cosmic-variance limited (with $\sigma$(r)=0.093), but show marginalized posterior peaks towards negative values at...
We search for the signature of parity-violating physics in cosmic microwave background, called birefringence, using Planck data release 4. initially find a birefringence angle β=0.30°±0.11° (68% C.L.) nearly full-sky data. The values β decrease as we enlarge Galactic mask, which can be interpreted effect polarized foreground emission. Two independent ways to model this are used mitigate systematic impact on different sky fractions. choose not assign cosmological significance measured value...
We present cosmological parameter constraints using maps from the last Planck data release (PR4). In particular, we detail an upgraded version of cosmic microwave background likelihood, HiLLiPoP , that is based on angular power spectra and relies a physical modeling foreground residuals in spectral domain. This new likelihood retains larger sky fraction (up to 75%) uses extended multipole range. Using this along with low- ℓ measurements LoLLiPoP derived ΛCDM parameters are good agreement...
<i>Context. <i/>The High Frequency Instrument (HFI) is one of the two focal instruments <i>Planck<i/> mission. It will observe whole sky in six bands 100 GHz–1 THz range.<i>Aims. HFI instrument designed to measure cosmic microwave background (CMB) with a sensitivity limited only by fundamental sources: photon noise CMB itself and residuals left after removal foregrounds. The high frequency provide full maps submillimetre sky, featuring mainly extended point source Systematic effects must be...
We propose a novel estimator of the polarization amplitude from single measurement its normally distributed $(Q,U)$ Stokes components. Based on properties Rice distribution and dubbed 'MAS' (Modified ASymptotic), it meets several desirable criteria:(i) values lie in whole positive region; (ii) is continuous; (iii) transforms smoothly with signal-to-noise ratio (SNR) Rayleigh-like shape to Gaussian one; (iv) unbiased reaches components' variance as soon SNR exceeds 2; (v) analytic can...
The polarization of the cosmic microwave background (CMB) can be used to search for parity-violating processes like that predicted by a Chern-Simons coupling light pseudoscalar field. Such an interaction rotates $E$ modes into $B$ in observed CMB signal effect known as birefringence. Even though isotropic birefringence confused with rotation produced miscalibration detectors' angles degeneracy between both effects is broken when Galactic foreground emission calibrator. In this work, we use...
Abstract We study the possibility of using LiteBIRD satellite B -mode survey to constrain models inflation producing specific features in CMB angular power spectra. explore a particular model example, i.e. spectator axion-SU(2) gauge field inflation. This can source parity-violating gravitational waves from amplification fluctuations driven by pseudoscalar “axionlike” field, rolling for few e-folds during The sourced exceed vacuum contribution at reionization bump scales about an order...
We analyze the cosmological constraints that Archeops (Benoît et al. 2003) places on adiabatic cold dark matter models with passive power-law initial fluctuations.Because its angular power spectrum has small bins in and large coverage down to COBE scales, provides a precise determination of first acoustic peak terms position at multipole l = 220 ± 6, height width.An analysis data combination other CMB datasets constrains baryon content Universe, Ω b h 2 0.022 +0.003 -0.004 , compatible...
The cosmic
We present Xspect, a method to obtain estimates of the angular power spectrum Cosmic Microwave Background (CMB) temperature anisotropies including analytical error bars developed for Archeops experiment. Cross-power spectra are computed from set maps and each them is in itself an unbiased estimate as long detector noises uncorrelated. Then, cross-power combined into final with analytically derived cross-correlation matrix. This presents three main useful properties : (1) no estimation noise...
Aims. Archeops is a balloon-borne experiment, mainly designed to measure the Cosmic Microwave Background (CMB) temperature anisotropies at high angular resolution (~12 arcmin). By-products of mission are shallow sensitivity maps over large fraction sky (about 30%) in millimetre and submillimetre range 143, 217, 353 545 GHz. From these maps, we produce catalog bright point sources.
EBEX is a NASA-funded balloon-borne experiment designed to measure the polarization of cosmic microwave background (CMB). Observations will be made using 1432 transition edge sensor (TES) bolometric detectors read out with frequency multiplexed SQuIDs. observe in three bands centered at 150, 250, and 410 GHz, 768, 384, 280 each band, respectively. This broad coverage provide valuable information about polarized foreground signals from dust. The sky modulated an achromatic half wave plate...
Our current understanding of the Universe is established through pristine measurements structure in cosmic microwave background (CMB) and distribution shapes galaxies tracing large scale (LSS) Universe. One key ingredient that underlies cosmological observables field sources observed assumed to be initially Gaussian with high precision. Nevertheless, a minimal deviation from Gaussianityis perhaps most robust theoretical prediction models explain Universe; itis necessarily present even...
We present the first determination of Galactic polarized emission at 353 GHz by Archeops.The data were taken during Arctic night February 7, 2002 after balloon-borne instrument was launched CNES from Swedish Esrange base near Kiruna.In addition to 143 and 217 frequency bands dedicated CMB studies, Archeops had one 545 six bolometers mounted in three polarization-sensitive pairs that used for foreground studies.We maps I, Q, U Stokes parameters over 17% sky with a 13 arcmin resolution (850...
The High Frequency Instrument of <i>Planck<i/> will map the entire sky in millimeter and sub-millimeter domain from 100 to 857 GHz with unprecedented sensitivity polarization (Δ<i>P<i/>/<i>T<i/><sub>cmb<sub/> ~ 4 × 10<sup>-6<sup/> for <i>P<i/> either <i>Q<i/> or <i>U<i/> <i>T<i/><sub>cmb<sub/> 2.7 K) at 100, 143, 217 353 GHz. It lead major improvements our understanding cosmic microwave background anisotropies polarized foreground signals. make high resolution measurements <i>E<i/>-mode...
We extend the pure pseudo-power-spectrum formalism proposed recently in context of cosmic microwave background polarized power spectra estimation by Smith (2006) to incorporate cross-spectra computed for multiple maps same sky area. present an implementation such a technique, paying particular attention calculation relevant window functions and mixing (mode-coupling) matrices. discuss relevance treatment residual $E/B$ leakage number considered apodizations as well compromises assumptions...
<i>Planck<i/> is a scientific satellite that represents the next milestone in space-based research related to cosmic microwave background, and many other astrophysical fields. was launched on 14 May of 2009 now operational. The uncertainty optical response its detectors key factor allowing achieve objectives. More than decade analysis measurements have gone into achieving required performances. In this paper, we describe main aspects optics are relevant science, estimated in-flight...
When combining cosmological and oscillations results to constrain the neutrino sector, question of propagation systematic uncertainties is often raised. We address this issue in context derivation an upper bound on sum masses ($\Sigma m_\nu$) with recent data. This work performed within ${{\mathrm{\Lambda{CDM}}}}$ model extended $\Sigma m_\nu$, for which we advocate use three mass-degenerate neutrinos. focus study linked foregrounds modelling CMB data analysis, impact present knowledge...
<i>Context. <i/>CMB experiments aiming at a precise measurement of the CMB polarization, such as Planck satellite, need strong polarized absolute calibrator on sky to accurately set detectors polarization angle and cross-polarization leakage. As most intense source in microwave angular scales few arcminutes, Crab nebula will be used for this purpose.<i>Aims. <i/>Our goal was measure characteristics 90 GHz with unprecedented precision.<i>Methods. <i/>The observations were carried out IRAM 30...
With the forthcoming release of high precision polarization measurements, such as from Planck satellite, it becomes critical to evaluate performance estimators for fraction and angle. These two physical quantities suffer a well-known bias in presence measurement noise, described Part I this series. In paper, II series, we explore extent which various may correct bias. Traditional frequentist are compared with recent estimators: one inspired by Bayesian analysis second following an asymptotic...
With the forthcoming release of high precision polarization measurements, such as from Planck satellite, metrology needs to improve. In particular, it is crucial take into account full knowledge noise properties when estimating fraction and angle, which suffer well-known biases. While strong simplifying assumptions have usually been made in analysis, we present a method for including covariance matrix Stokes parameters estimates distributions angle. We thereby quantify impact on biases...
Abstract We present a demonstration of the in-flight polarization angle calibration for JAXA/ISAS second strategic large class mission, LiteBIRD , and estimate its impact on measurement tensor-to-scalar ratio parameter, r using simulated data. generate set sky maps with CMB polarized foreground emission, inject instrumental noise offsets to 22 (partially overlapping) frequency channels. Our relies nulling EB cross correlation signal in each channel. This step has been carried out by two...
We present for the first time a coherent model of polarized Galactic synchrotron and thermal dust emissions which are main diffuse foreground measurement power spectra CMB fluctuations with Planck satellite mission. produce 3D models magnetic field including regular turbulent components, distribution matter in Galaxy, relativistic electrons grains. By integrating along line sight we construct maps emission each these compare them to currently available data. consider 408 MHz all-sky...
We present a cross-spectra based approach for the analysis of CMB data at large angular scales to constrain reionization optical depth $\tau$, tensor scalar ratio $r$ and amplitude primordial perturbations $A_s$. With respect pixel-based developed so far, using has unique advantage eliminate spurious noise bias give better handle over residual systematics, allowing efficiently combine cosmological information encoded in cross-frequency or cross-dataset spectra. two solutions deal with...