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HAL - OMP | |
| HAL : in2p3-00440256, version 1 |
| arXiv : 0912.1751 |
| DOI : 10.1051/0004-6361/200913834 |
| Fiche détaillée |  Récupérer au format |
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| Astronomy and Astrophysics 514 (2010) A70 |
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| Measurement of the Crab nebula polarization at 90 GHz as a calibrator for CMB experiments |
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| J. Aumont 1, 2L. Conversi |
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| (2010) |
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| CMB experiments aiming at a precise measurement of the CMB polarization, such as the Planck satellite, need a strong polarized absolute calibrator on the sky in order to accurately set the detectors polarization angle and the cross-polarization leakage. The Crab Nebula, as the most intense polarized source in the microwave sky at angular scales of few arcminutes, will be used for this purpose. Our goal was to measure the Crab nebula polarization characteristics at 90 GHz with an unprecedented precision. The observations were carried out with the IRAM 30m telescope employing the correlation polarimeter XPOL and using two orthogonally polarized receivers. We have processed the Stokes I, Q and U maps from our observations in order to compute the polarization angle and linear polarization fraction. The first is almost constant in the region of maximum emission in polarization with a mean value of alpha_Sky=152.1+/-0.2 deg and the second is found to reach a maximum of Pi=30% for the most polarized pixels. We find that a CMB experiment having a 5 arcmin circular beam will see a mean polarization angle of alpha_Sky=149.9+/-0.2 deg and a mean polarization fraction of Pi=8.8+/-0.2%. |
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| 1 : | Centre d'étude spatiale des rayonnements (CESR) |
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CNRS : UMR5187 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III |
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| 2 : | Institut d'astrophysique spatiale (IAS) |
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CNRS : UMR8617 – INSU – Université Paris XI - Paris Sud |
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| 3 : | Institut de RadioAstronomie Millimétrique (IRAM) |
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CNRS : UPS2074 |
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| 4 : | Instituto de RadioAstronomía Milimétrica (IRAM) |
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CNRS : UPS2074 |
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| 5 : | Laboratoire de Radio Astronomie de l'ENS (LRA) |
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CNRS : FRE2460 – Observatoire de Paris |
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| 6 : | Laboratoire de Physique Subatomique et de Cosmologie (LPSC) |
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CNRS : UMR5821 – IN2P3 – Université Joseph Fourier - Grenoble I – Institut Polytechnique de Grenoble - Grenoble Institute of Technology |
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| 7 : | AstroParticule et Cosmologie (APC) |
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CNRS : UMR7164 – IN2P3 – Observatoire de Paris – Université Paris VII - Paris Diderot – CEA : DSM/IRFU |
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| 8 : | Laboratoire de l'Accélérateur Linéaire (LAL) |
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CNRS : UMR8607 – IN2P3 – Université Paris XI - Paris Sud |
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| APC - Cosmologie et gravitation |
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| Thème(s) | : | Physique/Astrophysique/Cosmologie et astrophysique extra-galactique Planète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique |
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| Lien vers le texte intégral : |
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| http://fr.arXiv.org/abs/0912.1751 |
| in2p3-00440256, version 1 | |
| http://hal.in2p3.fr/in2p3-00440256 | |
| oai:hal.in2p3.fr:in2p3-00440256 | |
| Contributeur : Emmanuelle Vernay | |
| Soumis le : Jeudi 10 Décembre 2009, 08:57:52 | |
| Dernière modification le : Lundi 25 Juin 2012, 18:24:00 | |
