Papers by Guillaume Hurier
Cette thèse se focalise sur l'étude des amas de galaxies, via l'effet Sunyaev-Zel'dov... more Cette thèse se focalise sur l'étude des amas de galaxies, via l'effet Sunyaev-Zel'dovich (tSZ), qui consiste en l'interaction de ces même amas avec le fond diffus cosmologique. Pour ce faire j'ai utilisé les données expérimentale de l'instrument HFI du satellite PLANCK. Cette thèse ce découpe en trois parties majeures, (1) L'analyse et le traitement des données en temps, des données brut jusqu'au cartes du ciel, ce focalisant tout particulièrement sur les effets systématiques. (2) Le développement de méthode de séparation de sources, permettant la construction de cartes par émission astrophysique (tout particulièrement l'effet Sunyaev-Zel-dovich) à partir de données multi-fréquences. (3) L'analyse physique des cartes d'effet Sunyaev-Zel'dovich, produit par le gaz d'électron chaud présent dans les amas de galaxies. Ce travail permet la mise en place de contrainte, sur le profile de pression des amas de galaxies, sur la présence de f...
Astronomy & Astrophysics, 2021
The pressure of hot gas in groups and clusters of galaxies is a key physical quantity, which is d... more The pressure of hot gas in groups and clusters of galaxies is a key physical quantity, which is directly linked to the total mass of the halo and several other thermodynamical properties. In the wake of previous observational works on the hot gas pressure distribution in massive halos, we have investigated a sample of 31 clusters detected in both the Planck and Atacama Cosmology Telescope (ACT), MBAC surveys. We made use of an optimised Sunyaev-Zeldovich (SZ) map reconstructed from the two data sets and tailored for the detection of the SZ effect, taking advantage of both Planck coverage of large scales and the ACT higher spatial resolution. Our average pressure profile covers a radial range going from 0.04 × R500 in the central parts to 2.5 × R500 in the outskirts. In this way, it improves upon previous pressure-profile reconstruction based on SZ measurements. It is compatible, as well as competitive, with constraints derived from joint X-ray and SZ analysis. This work demonstrates...
Virial shocks around galaxy clusters are expected to show a cutoff in the thermal Sunyaev-Zel’dov... more Virial shocks around galaxy clusters are expected to show a cutoff in the thermal Sunyaev-Zel’dovich (SZ) signal, coincident with a leptonic ring. However, until now, leptonic signals were reported only in Coma and in stacked Fermi-LAT clusters, and an SZ shock signal was reported only in A2319. We point out that a few clusters — presently Coma, A2319, and A2142 — already show sharp drops in Planck SZ pressure near the virial radius, coincident with a LAT γ-ray excess. These signatures are shown to trace the virial shocks of the clusters, at joint medium to high confidence levels. The electron acceleration rates inferred from γ-rays are consistent with previous measurements. Lower limits of order a few are imposed on the shock Mach numbers.
Cosmological constraints from the cross-power spectrum between Sunyaev-Zel’dovich and X-ray surveys
Coincident Sunyaev–Zel’dovich and Gamma-Ray Signals from Cluster Virial Shocks
The Astrophysical Journal, 2020
Virial shocks around galaxy clusters are expected to show a cutoff in the thermal Sunyaev-Zel'... more Virial shocks around galaxy clusters are expected to show a cutoff in the thermal Sunyaev-Zel'dovich (SZ) signal, coincident with a leptonic ring. However, until now, leptonic virial signals were reported only in Coma and in stacked Fermi-LAT clusters, and an SZ virial shock signal was reported only in A2319. We point out that a few clusters --- presently Coma, A2319, and A2142 --- already show a sharp drop in Planck SZ pressure near the virial radius, coincident with a weak LAT $\gamma$-ray excess. These signatures are shown to trace the virial shocks of the clusters, at joint medium to high confidence levels. The electron acceleration rates inferred from $\gamma$-rays are consistent with previous measurements. The combined signal allows a separate measurement of the $\sim0.5\%$ acceleration efficiency and of the accretion rate. Lower limits of order a few are imposed on the shock Mach numbers.
Astronomy & Astrophysics, 2019
We present a synthetic galaxy lightcone specially designed for narrow-band optical photometric su... more We present a synthetic galaxy lightcone specially designed for narrow-band optical photometric surveys. To reduce time-discreteness effects, unlike previous works, we directly include the lightcone construction in the L-Galaxies semi-analytic model applied to the subhalo merger trees of the Millennium simulation. Additionally, we add a model for the nebular emission in star-forming regions, which is crucial for correctly predicting the narrow- and medium-band photometry of galaxies. Specifically, we consider, individually for each galaxy, the contribution of 9 different lines: Lyα (1216 Å), Hβ (4861 Å), Hα (6563 Å), [O II] (3727 Å, 3729 Å), [O III] (4959 Å, 5007 Å), [Ne III] (3870 Å), [O I] (6300 Å), [N II] (6548 Å, 6583 Å), and [S II] (6717 Å, 6731 Å). We validate our lightcone by comparing galaxy number counts, angular clustering, and Hα, Hβ, [O II], and [O III]5007 luminosity functions to a compilation of observations. As an application of our mock lightcones, we generated catalo...
Astronomy & Astrophysics, 2019
Magnetized plasmas within haloes of galaxies leave their footprint on the polarized anisotropies ... more Magnetized plasmas within haloes of galaxies leave their footprint on the polarized anisotropies of the cosmic microwave background. The two dominant effects of astrophysical haloes are Faraday rotation, which generates rotation of the plane of linear polarization, and Faraday conversion, which induces a leakage from linear polarization to circular polarization. We revisit these sources of secondary anisotropies by computing the angular power spectra of the Faraday rotation angle and the Faraday conversion rate by the large-scale structures. To this end, we use the halo model and we pay special attention to the impact of magnetic field projections. Assuming magnetic fields of haloes to be uncorrelated, we found a vanishing two-halo term, and angular power spectra peaking at multipoles ℓ ∼ 104. The Faraday rotation angle is dominated by the contribution of thermal electrons. For the Faraday conversion rate, we found that both thermal electrons and relativistic, non-thermal electrons ...
Astronomy & Astrophysics, 2016
Aims. We investigate the possible presence of diffuse radio emission in the intermediate redshift... more Aims. We investigate the possible presence of diffuse radio emission in the intermediate redshift, massive cluster PLCK G285.0-23.7 (z = 0.39, M 500 = 8.39 × 10 14 M ). Methods. Our 16 cm-band ATCA observations of PLCK G285.0-23.7 allow us to reach a rms noise level of ∼11 µJy/beam on the wide-band (1.1-3.1 GHz), full-resolution (∼5 arcsec) image of the cluster, making it one of the deepest ATCA images yet published. We also re-image visibilities at lower resolution in order to achieve a better sensitivity to low-surface-brightness extended radio sources. Results. We detect one of the lowest luminosity radio halos known at z > 0.35, characterised by a slight offset from the well-studied 1.4 GHz radio power vs. cluster mass correlation. Similarly to most known radio-loud clusters (i.e. those hosting diffuse non-thermal sources), PLCK G285.0-23.7 has a disturbed dynamical state. Our analysis reveals a similarly elongated X-ray and radio morphology. While the size of the radio halo in PLCK G285.0-23.7 is smaller than lower redshift radio-loud clusters in the same mass range, it shows a similar correlation with the cluster virial radius, as expected in the framework of hierarchical structure formation.
Http Www Theses Fr, Dec 10, 2012
En premier lieu je souhaiterais remercier tout particulièrement mes deux directeurs de thèse, Jua... more En premier lieu je souhaiterais remercier tout particulièrement mes deux directeurs de thèse, Juan Francisco Macías-Pérez et François-Xavier Désert pour avoir "supporté" mon entêtement et m'avoir offert 3 années de thèse captivantes. Encore merci à vous deux pour vos conseils avisés et la diversité des thématiques que vous m'avez proposées au cours de ma thèse. Je tiens ensuite à remercier les membres de mon jury Gilles Henri, Matthieu Tristram et Tony Banday pour leur présence et pour l'intérêt qu'ils ont porté à mes travaux. De même à mes deux rapporteurs José Alberto Rubiño-Martín et Jean-Luc Starck pour avoir accepté de relire mon manuscrit, particulièrement en cette période chargée au sein de la collaboration Planck. Merci également à tout le groupe Planck du LPSC pour m'avoir accueilli et permi de travailler dans un cadre sympathique et convivial au cours des mes stages de M1 et de M2 ainsi qu'au cours de ma thèse. Merci aussi au directeur du LPSC, Serge Kox, de m'avoir accueilli dans le laboratoire au cours de ma thèse. Merci également à toute la collaboration Planck pour m'avoir permi de travailler sur une expérience majeur pour la cosmologie de précision. Un énorme merci à tous ceux qui ont eut le malheur de corriger mes "photes d'ortaugrafffe" : Juan, Cécile, Céline, David, Lilian, Lauranne, Laurence, Romane et Rémi. Merci et bravo à ceux qui ont enduré ma présence dans leur bureau : Lauranne, Cyril, Fouad, Romane, Céline, Nicolas et Rémi . . . ainsi que Cécile, Barbara et Lilian. Merci à tous mes compagnons de galère thésard du LPSC, pour avoir su discuter de sujets improbables en pause café . . . Merci à tous mes amis non-physiciens, pour m'avoir permis de décrocher du monde scientifique pour de brefs moments. Finalement merci à ma famille, tous particulièrement à mes parents pour leur soutient, à ma soeur et à mon neveu Aaron . . . qui nous rappelle que le temps passe. viii Table des matières 8.7.2 Comparaison avec les prédictions théoriques .
Proceedings of XXIst International Europhysics Conference on High Energy Physics — PoS(EPS-HEP2011), 2012
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Papers by Guillaume Hurier