Simon Prunet

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Papers by Simon Prunet

VizieR Online Data Catalog: Planck early results. VIII. ESZ sample. (Planck+, 2011)

yCat, Feb 1, 2012

MPgrafic: A parallel MPI version of Grafic-1

CMB Anistropies: Status and Boomerang

Particles, Strings and Cosmology (PASCOS 99), 2000

Measuring CMB polarization with Boomerang

New Astronomy Reviews, 2003

Boomerang is a balloon-borne telescope designed for long duration (LDB) flights around Antarctica... more Boomerang is a balloon-borne telescope designed for long duration (LDB) flights around Antarctica. The second LDB Flight of Boomerang took place in January 2003. The primary goal of this flight was to measure the polarization of the CMB. The receiver uses polarization sensitive bolometers at 145 GHz. Polarizing grids provide polarization sensitivity at 245 and 345 GHz. We describe the Boomerang telescope noting changes made for 2003 LDB flight, and discuss some of the issues involved in the measurement of polarization with bolometers. Lastly, we report on the 2003 flight and provide an estimate of the expected results.

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Planckintermediate results. XXVI. Optical identification and redshifts ofPlanckclusters with the RTT150 telescope

Astronomy & Astrophysics, 2015

Planck intermediate results. XXVI. Optical identification and redshifts of Planck clusters with t... more

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Parameters extraction by Planck for a CDM model with BSI steplike primordial spectrum and cosmological constant

We consider a class of spatially flat cold dark matter (CDM) models, with a cosmological constant... more We consider a class of spatially flat cold dark matter (CDM) models, with a cosmological constant and a broken-scale-invariant (BSI) steplike primordial spectrum of adiabatic perturbations, previously found to be in very good agreement with observations. Performing a Fisher matrix analysis, we show that some free parameters (defining the step) of our BSI model could be extracted with remarkable accuracy by the Planck satellite, thanks to the polarisation anisotropies measurements. Further, cosmological parameters could still be found with very good precision, despite a larger number of free parameters than in the simplest inflationary models.

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Imaging the Early Universe with the Boomerang Experiment

2001: A Relativistic Spacetime Odyssey - Experiments and Theoretical Viewpoints on General Relativity and Quantum Gravity - Proceedings of the 25th Johns Hopkins Workshop on Current Problems in Particle Theory, 2003

... 2.2 Data Analysis The data were edited for known instrument glitches, temperature fluctuation... more

Extended Mosaic Observations with the Cosmic Background Imager

The Astrophysical Journal, 2004

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On the onset of stochasticity in Λ cold dark matter cosmological simulations

Monthly Notices of the Royal Astronomical Society, 2008

The onset of stochasticity is measured in ΛCDM cosmological simulations using a set of classical ... more The onset of stochasticity is measured in ΛCDM cosmological simulations using a set of classical observables. It is quantified as the local derivative of the logarithm of the dispersion of a given observable (within a set of different simulations differing weakly through their initial realization), with respect to the cosmic growth factor. In an Eulerian framework, it is shown here that chaos appears at small scales, where dynamic is non-linear, while it vanishes at larger scales, allowing the computation of a critical transition scale corresponding to ∼ 3.5Mpc/h. This picture is confirmed by Lagrangian measurements which show that the distribution of substructures within clusters is partially sensitive to initial conditions, with a critical mass upper bound scaling roughly like the perturbation's amplitude to the power 0.15. The corresponding characteristic mass, M crit = 2 10 13 M ⊙ , is roughly of the order of the critical mass of non linearities at z = 1 and accounts for the decoupling induced by the dark energy triggered acceleration. The sensitivity to detailed initial conditions spills to some of the overall physical properties of the host halo (spin and velocity dispersion tensor orientation) while other "global" properties are quite robust and show no chaos (mass, spin parameter, connexity and center of mass position). This apparent discrepancy may reflect the fact that quantities which are integrals over particles rapidly average out details of difference in orbits, while the other observables are more sensitive to the detailed environment of forming halos and reflect the non-linear scale coupling characterizing the environments of halos.

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Planck2013 results. III. LFI systematic uncertainties

Astronomy & Astrophysics, 2014

We present the current estimate of instrumental and systematic effect uncertainties for the Planc... more We present the current estimate of instrumental and systematic effect uncertainties for the Planck-Low Frequency Instrument relevant to the first release of the Planck cosmological results. We give an overview of the main effects and of the tools and methods applied to assess residuals in maps and power spectra. We also present an overall budget of known systematic effect uncertainties, which are dominated by sidelobe straylight pickup and imperfect calibration. However, even these two effects are at least two orders of magnitude weaker than the cosmic microwave background fluctuations as measured in terms of the angular temperature power spectrum. A residual signal above the noise level is present in the multipole range < 20, most notably at 30 GHz, and is probably caused by residual Galactic straylight contamination. Current analysis aims to further reduce the level of spurious signals in the data and to improve the systematic effects modelling, in particular with respect to straylight and calibration uncertainties.

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Planckearly results. XXVI. Detection withPlanckand confirmation byXMM-Newtonof PLCK G266.6–27.3, an exceptionally X-ray luminous and massive galaxy cluster atz ~ 1

Astronomy & Astrophysics, 2011

Planck early results Special feature Planck early results. XXVI. Detection with Planck and confir... more

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Dataflow Algorithm aRchitecture co-design of SKA pipeline for Exascale Radio Astronomy

HAL (Le Centre pour la Communication Scientifique Directe), Jun 24, 2021

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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VizieR Online Data Catalog: Anomalous microwave emission in Galactic clouds (Planck+, 2014)

Anomalous microwave emission (AME) is believed to be due to electric dipole radiation from small ... more Anomalous microwave emission (AME) is believed to be due to electric dipole radiation from small spinning dust grains. The aim of this paper is a statistical study of the basic properties of AME regions and the environment in which they emit. We used WMAP and Planck maps, combined with ancillary radio and IR data, to construct a sample of 98 candidate AME sources, assembling SEDs for each source using aperture photometry on 1?-smoothed maps from 0.408GHz up to 3000GHz. Each spectrum is fitted with a simple model of free-free, synchrotron (where necessary), cosmic microwave background (CMB), thermal dust, and spinning dust components. We find that 42 of the 98 sources have significant (>5sigma) excess emission at frequencies between 20 and 60GHz. An analysis of the potential contribution of optically thick free-free emission from ultra-compact HII regions, using IR colour criteria, reduces the significant AME sample to 27 regions. The spectrum of the AME is consistent with model s...

MontePython 3: Parameter inference code for cosmology

Uncertainty-aware learning for improvements in image quality of the Canada–France–Hawaii Telescope

Monthly Notices of the Royal Astronomical Society, 2021

We leverage state-of-the-art machine learning methods and a decade’s worth of archival data from ... more We leverage state-of-the-art machine learning methods and a decade’s worth of archival data from Canada–France–Hawaii Telescope (CFHT) to predict observatory image quality (IQ) from environmental conditions and observatory operating parameters. Specifically, we develop accurate and interpretable models of the complex dependence between data features and observed IQ for CFHT’s wide-field camera, MegaCam. Our contributions are several-fold. First, we collect, collate, and reprocess several disparate data sets gathered by CFHT scientists. Second, we predict probability distribution functions of IQ and achieve a mean absolute error of ∼0.07 arcsec for the predicted medians. Third, we explore the data-driven actuation of the 12 dome ‘vents’ installed in 2013–14 to accelerate the flushing of hot air from the dome. We leverage epistemic and aleatoric uncertainties in conjunction with probabilistic generative modelling to identify candidate vent adjustments that are in-distribution (ID); fo...

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CMB Analysis of Boomerang & Maxima & the Cosmic Parameters {Ωtot,Ωbh2, Ωcdmh2, ΩΛ, ns}

Symposium - International Astronomical Union, 2005

We show how estimates of parameters characterizing inflation-based theories of structure formatio... more We show how estimates of parameters characterizing inflation-based theories of structure formation localized over the past year when large scale structure (LSS) information from galaxy and cluster surveys was combined with the rapidly developing cosmic microwave background (CMB) data, especially from the recent Boomerang and Maxima balloon experiments. All current CMB data plus a relatively weak prior probability on the Hubble constant, age and LSS points to little mean curvature (Ωtot = 1.08±0.06) and nearly scale invariant initial fluctuations (ns = 1.03±0.08), both predictions of (non-baroque) inflation theory. We emphasize the role that degeneracy among parameters in the Lpk = 212 ± 7 position of the (first acoustic) peak plays in defining the Ωtot range upon marginalization over other variables. Though the CDM density is in the expected range (Ωcdmh2 = 0.17 ± 0.02), the baryon density Ωbh2 = 0.030 ± 0.005 is somewhat above the independent 0.019 ± 0.002 nucleosynthesis estimates...

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The quintessential CMB, past & future

AIP Conference Proceedings, 2001

The past, present and future of cosmic microwave background (CMB) anisotropy research is discusse... more The past, present and future of cosmic microwave background (CMB) anisotropy research is discussed, with emphasis on the Boomerang and Maxima balloon experiments. These data are combined with large scale structure (LSS) information derived from local cluster abundances and galaxy clustering and high redshift supernova (SN1) observations to explore the inflation-based cosmic structure formation paradigm. Here we primarily focus on a simplified inflation parameter set, {ω b , ω cdm , Ω tot , Ω Q , w Q , n s , τ C , σ 8 }. After marginalizing over the other cosmic and experimental variables, we find the current CMB+LSS+SN1 data gives Ω tot = 1.04±0.05, consistent with (non-baroque) inflation theory. Restricting to Ω tot = 1, we find a nearly scale invariant spectrum, n s = 1.03 ± 0.07. The CDM density, ω cdm = 0.17 ± 0.02, is in the expected range, but the baryon density, ω b ≡ Ω b h 2 = 0.030 ± 0.004, is slightly larger than the current 0.019 ± 0.002 Big Bang Nucleosynthesis estimate. Substantial dark (unclustered) energy is inferred, Ω Q ≈ 0.68 ± 0.05, and CMB+LSS Ω Q values are compatible with the independent SN1 estimates. The dark energy equation of state, parameterized by a quintessence-field pressure-to-density ratio w Q , is not well determined by CMB+LSS (w Q < −0.3 at 95% CL), but when combined with SN1 the resulting w Q < −0.7 limit is quite consistent with the w Q =−1 cosmological constant case. Though forecasts of statistical errors on parameters for current and future experiments are rosy, rooting out systematic errors will define the true progress.

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Optimal fitting of Gaussian-apodized or under-resolved emission lines in Fourier transform spectra providing new insights on the velocity structure of NGC 6720

Monthly Notices of the Royal Astronomical Society, 2016

An analysis of the kinematics of NGC 6720 is performed on the commissioning data obtained with SI... more An analysis of the kinematics of NGC 6720 is performed on the commissioning data obtained with SITELLE, the Canada-France-Hawaii Telescope's new imaging Fourier transform spectrometer. In order to measure carefully the small broadening effect of a shell expansion on an unresolved emission line, we have determined a computationally robust implementation of the convolution of a Gaussian with a sinc instrumental line shape which avoids arithmetic overflows. This model can be used to measure line broadening of typically a few km s −1 even at low spectral resolution (R < 5000). We have also designed the corresponding set of Gaussian apodizing functions that are now used by ORBS, the SITELLE's reduction pipeline. We have implemented this model in ORCS, a fitting engine for SITELLE's data, and used it to derive the [S II] density map of the central part of the nebula. The study of the broadening of the [N II] lines shows that the main ring and the central lobe are two different shells with different expansion velocities. We have also derived deep and spatially resolved velocity maps of the halo in [N II] and Hα and found that the brightest bubbles are originating from two bipolar structures with a velocity difference of more than 35 km s −1 lying at the poles of a possibly unique halo shell expanding at a velocity of more than 15 km s −1 .

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Commissioning SITELLE: an imaging Fourier transform spectrometer for the Canada France Hawaii Telescope

Ground-based and Airborne Instrumentation for Astronomy VI, 2016

The SITELLE Imaging Fourier Transform Spectrometer was successfully commissioned at the Canada Fr... more The SITELLE Imaging Fourier Transform Spectrometer was successfully commissioned at the Canada France Hawaii Telescope starting in July 2015. Here we discuss the commissioning process, the outcome of the early tests on-sky as well as the ensuing work to optimize the modulation efficiency at large optical path difference and the image quality of the instrument.

Images of the early universe from the BOOMERanG experiment

AIP Conference Proceedings, 2001

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