The NIKA polarimeter on science targets. Crab nebula observations at 150 GHz and dual-band polarization images of Orion Molecular Cloud OMC-1

TL;DR

This paper describes the polarization system of the NIKA camera, presents polarization observations of the Crab nebula and Orion Molecular Cloud, and discusses the implications for future NIKA2 polarization studies in astrophysics.

Contribution

It introduces the polarization system of NIKA and demonstrates its capability to detect polarization in various astrophysical targets, paving the way for NIKA2 polarization observations.

Findings

Successful polarization detection of Crab nebula and Orion OMC-1

Development of techniques to handle systematics in polarization measurements

Foundation for future NIKA2 polarization studies

Abstract

We present here the polarization system of the NIKA camera and give a summary of the main results obtained and performed studies on Orion and the Crab nebula. The polarization system was equipped with a room temperature continuously rotating multi-mesh half wave plate and a grid polarizer facing the NIKA cryostat window. NIKA even though less sensitive than NIKA2 had polarization capability in both 1 and 2 millimiter bands. NIKA polarization observations demonstrated the ability of such a technology in detecting the polarization of different targets, compact and extended sources like the Crab nebula and Orion Molecular Cloud region OMC-1. These measurements together with the developed techniques to deal with systematics, opened the way to the current observations of NIKA2 in polarization that will provide important advances in the studies of galactic and extra-galactic emission and magnetic fields.