Context: Direct imaging surveys often produce a large number of candidate companions for the observed stars, not all of which can be followed up on and confirmed or rejected as exoplanets. Aims: We...Show moreContext: Direct imaging surveys often produce a large number of candidate companions for the observed stars, not all of which can be followed up on and confirmed or rejected as exoplanets. Aims: We aim to search for archival data from the Spectro-Polarimetic High contrast imager for Exoplanets REsearch (SPHERE) and assess the nature of the candidate companions identified in the Gemini NICI Planet-Finding Campaign in 2013. Methods: We reduce the archival data from SPHERE for 10 NICI targets for which candidate companions were identified, using PynPoint. We extracted the astrometry of point sources in the images and evaluated whether these objects were consistent with either bound orbits or background trajectories. Results: We could rule out 105 out of 130 candidate companions from the NICI campaign as background contaminants. 25 remain ambiguous and 31 new candidates were discovered. Conclusions: Even though we did not detect anything, this study is still enormously important, as wide-orbit companions might be missed otherwiseShow less
Context. Much data from the integral field spectroscope (IFS) of SPHERE, the high contrast imager of the VLT, of circumstellar disks is yet unpublished, since this data is always collected in...Show moreContext. Much data from the integral field spectroscope (IFS) of SPHERE, the high contrast imager of the VLT, of circumstellar disks is yet unpublished, since this data is always collected in parallel with IRDIS, which is much easier to reduce and analyze. Aims. We search for a good and reliable way to reduce raw IFS data and study the effects of different post-processing methods on the morphology of protoplanetary disks. Methods. We used the common pipeline of ESO to reduce spatially resolved spectral IFS data (YJ band) of RXJ1615.3-3255 and applied classical ADI, classical SDI and classical RDI on the data. Results. We detected a ring, an arc and an inner disk component in both the ADI and SDI image, the ring is detected in the RDI image as well. We conclude that we can trust the SDI data the best around the minor axis of the ring since ADI and RDI have to deal with self-subtraction and over subtraction in that region, the other parts of the ring can be trusted the best in the ADI and RDI data. The disk signal appears to be red, but further research is needed to conclude whether this effect is astrophysical or not.Show less
Recent advancements in imaging techniques have enabled the detection of thousands of exoplanets, as well as the characterization of a multitude of protoplanetary disks. These disks are believed to...Show moreRecent advancements in imaging techniques have enabled the detection of thousands of exoplanets, as well as the characterization of a multitude of protoplanetary disks. These disks are believed to form planets, but have mostly been observed around low mass T Tauri stars. No observations of disks around high mass Herbig Be stars exist, raising the question whether planets and especially giant planets can form there. Using archival data from VLT/SPHERE/IRDIS, one of the world’s best direct imagers for exoplanets and protoplanetary disks, we have attempted to image the disk of such a Herbig Be star, MWC147 (alias V700 Mon & HD259431). For this data reduction, a variety of correction techniques are demonstrated and compared against each other. The resulting images reveal the prescence of a second companion, dubbed MWC147 C, and a large bow shaped structure. Furthermore, a model of VLT/SPHERE/ZIMPOL was designed to quantify the effects of instrumental polarization and crosstalk on the polarimetric efficiency of the instrument. Finally, an observing proposal for VLT/SPHERE was written with the goal of obtaining better data of MWC147, such that the bow shaped structure and disk of MWC147 could be better characterized.Show less
