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Polarimetry at millimeter wavelengths with the instruments NIKA and NIKA2

Abstract : Magnetic fields play a crucial role in a large number of astrophysical processes from Galactic to Cosmological scales. They can be traced via observations of dust polarization as demonstrated by several experiments like Archeops, SCUBA, ALMA and the Planck satellite. In particular, low resolution observations of dust polarization have demonstrated that Galactic filamentary structures, where star formation takes place, are associated to well organized magnetic fields. High angular resolution polarization observations could probe the physics at small angular scales and complete the current understanding of the star formation process: this is one of the main objectives of the NIKA2 camera. In NIKA2 as well as in its prototype, NIKA, the polarization reconstruction consists in a quasi-simultaneous detection of the Stokes parameters Q and U, describing the linear polarization of the light. This is achieved thanks to the continuous rotation of a modulator, a Half Wave Plate (HWP) and a polarizer coupled to the fast response of the Lumped Element Kinetic Inductance Detectors (LEKIDs). This PhD thesis focuses on the development of the NIKA polarimeter and consequently that of NIKA2, which observes the sky in intensity and polarization from the IRAM 30 m telescope located in the Sierra Nevada (Spain). It presents the instrumental characterization of the instrumental setup, the dedicated data analysis pipeline to reconstruct the polarization properties of the observed source at the telescope and the science verification using known compact and extended sources observations.
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https://hal.archives-ouvertes.fr/tel-01467862
Contributor : Alessia Ritacco Connect in order to contact the contributor
Submitted on : Tuesday, February 14, 2017 - 5:49:44 PM
Last modification on : Tuesday, May 11, 2021 - 11:36:50 AM
Long-term archiving on: : Monday, May 15, 2017 - 5:52:07 PM

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  • HAL Id : tel-01467862, version 1

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Alessia Ritacco. Polarimetry at millimeter wavelengths with the instruments NIKA and NIKA2. Instrumentation and Methods for Astrophysic [astro-ph.IM]. Laboratoire de Physique Subatomique et de Cosmologie; Université Grenoble - Alpes, 2016. English. ⟨NNT : ⟩. ⟨tel-01467862v1⟩

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