arXiv subjects

E. Pointecouteau

Publications and source records attributed to E. Pointecouteau.

130 records · Page 8Linked to original sources

arXiv2000

Extended SZ map of the most luminous X-ray cluster, RXJ1347-1145

We present in this letter a high resolution (22'' FWHM) extended map at 2.1mm of the Sunyaev-Zel'dovich effect toward the most luminous X-ray cluster, RXJ1347-1145. These observations have been performed with the DIABOLO photometer working at the focus of the 30m IRAM radiotelescope. We have derived a projected gas mass of $(1.1 \pm 0.1)\times 10^{14} h_{50}^{-5/2}$M$_{\odot}$ within an angular radius of $θ=74''$ (ie: projected radius of 0.6Mpc, $H_{0}=50$km/s/Mpc, $Ω_m=0.3$, $Ω_Λ=0.7$). This result matches very well the expected gas mass from the cluster models of X-ray data. With an unprecedented sensitivity level our measurement does not show significant departure from a spherical distribution. The data analysis also allows us to characterize the 2.1mm flux of a well known radio source lying in the center of the cluster: $F_{RS}(2.1\textrm{mm})=5.7\pm 1.6$mJy.

astro-ph↗

arXiv1999

A Sunyaev-Zel'dovich map of the massive core in the luminous X-ray cluster RXJ1347-1145

We have mapped the Sunyaev-Zel'dovich decrement (hereafter SZ) in the direction of the most luminous X-ray cluster known to date, RXJ1347-1145, at z=0.451. This has been achieved with an angular resolution of about 23'' using the Diabolo photometer running on the IRAM 30 meter radio telescope. We present here a map of the cluster central region at 2.1mm. The Comptonization parameter towards the cluster center, $\yc=(12.7^{+2.9}_{-3.1})\times 10^{-4}$, corresponds to the deepest SZ decrement ever observed. Using the gas density distribution derived from X-ray data, this measurement implies a gas temperature $\te=16.2 \pm 3.8$ keV. The resulting total mass of the cluster is, under hydrostatic equilibrium, $M(r<1 Mpc)=(1.0 \pm 0.3) \times 10^{15} M_\odot$ for a corresponding gas fraction $f_{gas}(r<1 Mpc)=(19.5 \pm 5.8)%$.

astro-ph↗

arXiv1998

First measurement of the submillimetre Sunyaev-Zel'dovich effect

We report the first detection of the Sunyaev-Zel'dovich increment on the cosmic microwave background (CMB) at submillimetre wavelengths in the direction of a cluster of galaxies.It was achieved towards the rich cluster Abell 2163, using the PRONAOS 2-metre stratospheric telescope. Together with data from the SuZIE, Diabolo, and ISO-PHT experiments, these measurements, for the first time, give a complete picture of the far-infrared to millimetre spectral energy distribution of the diffuse emission toward a cluster of galaxies. It clearly shows the positive and negative parts of the S.Z. effect and also a positive signal at short wavelengths that can be attributed to foreground dust in our galaxy.

astro-ph↗

arXiv1998

Determination of the hot intracluster gas temperature from submillimeter measurements

Measurements of the Sunyaev-Zeldovich (hereafter SZ) distorsion of the cosmic microwave background can give interesting physical informations on clusters of galaxies, provided that the electronic temperature of the gas is known. Previous attempts to do so have used the electronic temperature determination obtained from the X-ray spectra. However, if the intergalactic gas is not homogeneous, the X-ray emission will trace the denser component, and the temperature determination may not be relevant for the lower density gas which is dominating the SZ measurements. Moreover, the X-ray brightness decreases very rapidly with the distance, which is not the case for the SZ effect. Distant clusters might be detected from SZ measurements, whereas they are inaccessible to X-ray observations. For these reasons, we have investigated the possibility to derive the electronic temperature of the gas from the SZ measurements in the submillimeter range (lambda ~ 300-600 micro-m). We show that given the sensitivities of the future submillimeter space missions Planck Surveyor and FIRST, the electronic temperature of massive clusters (Y_center=3*10^{-4}) can be determined with an accuracy ranging from 1 to 4 keV depending on its distance and the data avalaible.

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