18 février 2020Astro lunch 12.06.2018

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Le 12 juin 2018
De 12h45 à 13h45

Frederic Marin (ObAS)

An exceptional disclosure of the hidden AGN in NGC 1068 thanks to 50 years of broadband polarimetric observation

In this contribution, I present the first broadband polarization spectrum of an active galactic nuclei (AGN) by compiling the 0.1 – 100 microns continuum polarization of NGC 1068 from more than 50 years of observations. Despite the diversity of instruments, the observed spectrum of linear polarization has distinctive wavelength-dependent signatures that can be related to the AGN and host galaxy physics. To isolate the AGN component, I reconstruct the spectral energy distribution of NGC 1068 and estimate the fraction of starlight in the observed continuum flux. By doing so, I successfully remove host contamination from the synthetic polarized spectrum. I also investigate the effect of aperture on the observed polarization and use this information to 1) constrain the extension of the narrow line region and 2) determine the B-band and K-band polarization from the host. Finally, I show that the parsec-scale morphological and magnetic geometries remained stable for more than 50 years.