POLARIZATION

Biosignatures of the Earth. I. Airborne spectropolarimetric detection of photosynthetic life

Context. Homochirality is a generic and unique property of life on Earth and is considered a universal and agnostic biosignature. Homochirality induces fractional circular polarization in the incident light that it reflects. Because this circularly …

Polarimetric imaging mode of VLT/SPHERE/IRDIS. I. Description, data reduction, and observing strategy

Context. Polarimetric imaging is one of the most effective techniques for high-contrast imaging and for the characterization of protoplanetary disks, and it has the potential of becoming instrumental in the characterization of exoplanets. The …

Polarimetric imaging mode of VLT/SPHERE/IRDIS. II. Characterization and correction of instrumental polarization effects

Context. Circumstellar disks and self-luminous giant exoplanets or companion brown dwarfs can be characterized through direct- imaging polarimetry at near-infrared wavelengths. SPHERE/IRDIS at the Very Large Telescope has the capabilities to perform …

Polarimetric imaging of circumstellar disks. I. Artifacts due to limited angular resolution

Context. Polarimetric images of circumstellar environments, even when corrected with adaptive optics, have a limited angular resolution. Finite resolution greatly affects polarimetric images because of the canceling of adjacent polarization signals …

BP Piscium: its flaring disc imaged with SPHERE/ZIMPOL$^★$

Whether BP Piscium (BP Psc) is either a pre-main sequence T Tauri star at d ensuremath≈ 80 pc, or a post-main sequence G giant at d ensuremath≈ 300 pc is still not clear. As a first-ascent giant, it is the first to be observed with a molecular and …

Instrumental polarisation at the Nasmyth focus of the E-ELT

The åisebox-0.5ex~39-m European Extremely Large Telescope (E-ELT) will be the largest telescope ever built. This makes it particularly suitable for sensitive polarimetric observations, as polarimetry is a photon-starved technique. However, the …

Three-dimensional magnetic and abundance mapping of the cool Ap star HD 24712 . I. Spectropolarimetric observations in all four Stokes parameters

Context. High-resolution spectropolarimetric observations provide simultaneous information about stellar magnetic field topologies and three-dimensional distributions of chemical elements. High- quality spectra in the Stokes IQUV parameters are …

Are there tangled magnetic fields on HgMn stars?

Context. Several recent spectrophotometric studies failed to detect significant global magnetic fields in late-B HgMn chemically peculiar stars, but some investigations have suggested the presence of strong unstructured or tangled fields in these …

The effects of disk and dust structure on observed polarimetric images of protoplanetary disks

Context. Imaging polarimetry is a powerful tool for imaging faint circumstellar material. It is a rapidly developing field with great promise for diagnostics of both the large-scale structures and the small-scale details of the scattering particles. …

No magnetic field in the spotted HgMn star ensuremathμ Leporis

Context. Chemically peculiar stars of the mercury-manganese (HgMn) type represent a new class of spotted late-B stars, in which evolving surface chemical inhomogeneities are apparently unrelated to the presence of strong magnetic fields but are …