POLLUX is a high-resolution, UV spectropolarimeter proposed for the
LUVOIR-A architecture (15-meter primary mirror).
The instrument Phase 0 study started in January 2017. It is led by LAM
and LESIA with the support of the French Space Agency (CNES), and
performed by a consortium of European scientists.
POLLUX is a spectropolarimeter working in three channels. For practical reasons we refer to these as NUV (200 - 400 nm), MUV (118.5 - 200 nm), and FUV (90 - 124.5 nm). Each channel is equipped with its own dedicated polarimeter followed by a high-resolution spectrograph. This design allows to achieve high spectral resolving power with feasible and affordable values of the detector length, the camera optics field of view, and the overall size of the instrument. It also allows us to use dedicated optical elements, coatings, detector, and polarimeter for each band, hence gaining in efficiency. The MUV + NUV channels are recorded simultaneously, while the FUV is recorded separately. POLLUX can be operated in pure spectroscopy mode or in spectropolarimetric mode. The full polarimeters are thus retractable in the MUV and NUV to allow the pure spectroscopic mode. In the FUV only the modulator is retractable. The analyzer is kept in the optical path to direct the beam towards the collimator.
POLLUX will address a range of questions at the core of the LUVOIR
Science portfolio. The combination of high resolution and broad
coverage of the UV bandpass will resolve narrow UV emission and
absorption lines originating in diffuse media, thus permitting the
study of the baryon cycle over cosmic time: from galaxies forming
stars out of interstellar gas and grains, and stars forming planets,
to the various forms of feedback into the interstellar and
intergalactic medium (ISM and IGM), and active galactic nuclei (AGN).
UV circular and linear polarimetry will reveal the magnetic fields for
a wide variety of objects for the first time, from AGN outflows to a
diverse range of stars, stellar explosions (both supernovae and their
remnants), the ISM and IGM. It will enable detection of polarized
light reflected from exoplanets (or their circumplanetary material and
moons), characterization of the magnetospheres of stars and planets
(and their interactions), and measurements of the influence of
magnetic fields at the (inter)galactic scale.