arXiv subjects

J. M. Lamarre

Publications and source records attributed to J. M. Lamarre.

4 recordsLinked to original sources

arXiv2011

Planck early results XIV: ERCSC validation and extreme radio sources

Planck's all sky surveys at 30-857 GHz provide an unprecedented opportunity to follow the radio spectra of a large sample of extragalactic sources to frequencies 2-20 times higher than allowed by past, large area, ground-based surveys. We combine the results of the Planck Early Release Compact Source Catalog (ERCSC) with quasi-simultaneous ground-based observations, as well as archival data, at frequencies below or overlapping Planck frequency bands, to validate the astrometry and photometry of the ERCSC radio sources and study the spectral features shown in this new frequency window opened by Planck. The ERCSC source positions and flux density scales are found to be consistent with the ground-based observations. We present and discuss the spectral energy distributions (SEDs) of a sample of "extreme" radio sources to illustrate the richness of the ERCSC for the study of extragalactic radio sources. Variability is found to play a role in the unusual spectral features of some of these sources.

astro-ph.CO↗

arXiv2003

The Planck High Frequency Instrument, a 3rd generation CMB experiment, and a full sky submillimeter survey

The High Frequency Instrument (HFI) of Planck is the most sensitive CMB experiment ever planned. Statistical fluctuations (photon noise) of the CMB itself will be the major limitation to the sensitivity of the CMB channels. Higher frequency channels will measure galactic foregrounds. Together with the Low Frequency Instrument, this will make a unique tool to measure the full sky and to separate the various components of its spectrum. Measurement of the polarization of these various components will give a new picture of the CMB. In addition, HFI will provide the scientific community with new full sky maps of intensity and polarization at six frequencies, with unprecedented angular resolution and sensitivity. This paper describes the logics that prevailed to define the HFI and the performances expected from this instrument. It details several features of the HFI design that have not been published up to now.

astro-ph↗

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↗