We describe here the data that have been processed at the HC-DC processing centre. We currently support SPHERE data.
SPHERE DATA
The main scientific objective of the SPHERE instrument at VLT (Spectro-Polarimetric High-contrast Exoplanet REsearch) is to detect and characterize, using direct imaging techniques, young giant exoplanets orbiting around nearby stars. This instrument also allows to detect and characterize disks around young stars in which planet forms. This is a huge challenge since these planets lie very close to their host star and have a much smaller luminosity (typically 100000 times less than their host star). SPHERE combine several advanced techniques (extreme adaptive optics, coronagraphy, differential imager and spectro-imager in the visible and near infrared) and include three scientific instruments : IRDIS (differential imaging and polarimetry in the infrared), IFS (field spectrograph in the infrared), and ZIMPOL (differential polarimetric imaging in the visible).
Perimeter: SPHERE data releases as of SEPTEMBER 2024
| Reduced and available | Reduction in progress | Estimate of future releases | |
|---|---|---|---|
| Day time calibrations | All IRDIS/IFS existing calibrations are available | Calibrations from yesterday | Automatically up-to-date with at most 48hrs delay |
| IRDIS/IFS ESO periods | SVT ; P95-P104 | >P106 SHINE/all | 2024-2025 |
| Corresponding dates | 2014-10-01 to 2020-03-31 | ||
| ZIMPOL reductions | P95-P98 | Fall 2024 | |
| Corresponding dates | |||
| Other comments | Some SVT and commissioning data not reduced | – | – |
Statistics
The SPHERE reduced data cover most of P95-P104, i.e. 5 years of observations. As of June 2024, our full data base contains reduced data for 3225 stars, some of them observed several times. The statistics are shown below in terms of spectral type, luminosity class, and G magnitude (informations from CDS/SIMBAD). The database also includes reduced data for about 300 non-stellar targets (mostly solar system objects, AGN, stellar clusters), not taken into account in those graphs.
SUPPORTED MODES
| Instrument | Supported modes | Mode support in progress | Mode not supported yet |
|---|---|---|---|
| IFS | ALL modes, ADI/ASDI | – | – |
| IRDIS | Single and dual-band imaging ADI/ASDI | Polarimetry | LSS ; SAM |
| ZIMPOL | – | All modes (intensity and polarimetry) | – |
Algorithms
Level 2 data includes residual maps after ADI or ASDI processing. If using the DIVA+ interface to request the data, the used algorithm can be identified in the field “reduction_information”. If using the processing center client, they can be identified by the field “Reference” in the process brower when using the client (see FAQ) and in the directories after retrieval. The algorithms currently implemented are the following:
- NoADI : simple stacking of the master cubes
- cADI : Classical Angular Differential Imaging (Marois et al. 2006, Lafrenière et al 2007)
- TLOCI : Flavor of Angular Differential Imaging based on Locally Optimised Combination of Images (Marois et al. 2011, Galicher et al 2018)
- PCA : Flavor of Angular Differential Imaging based on Principal Component Analysis
Data levels
Our pipeline basic reduction draws on the ESO public pipeline supplemented by several IDL/Python routines improving the quality of the reduction and the ability to deal with poor/heterogeneous dataset. For the SPHERE data, we provide data corresponding to level 0 to 3. We also calibrate the data in wavelength, flux and astrometry and present the outputs of these basic reduction steps (’Level 1 data’) as 4D datacubes (x,y,nframes, lambda) as commonly used in high contrast imaging. We also propose a complete ADI and/or SDI reduction (’Level 2 data’) using several different algorithms from the SpeCal routine set (Galicher et al. 2018).
Level 3 has been obtained by the SPHERE consortium for the SHINE survey (F150 release, i.e. first part of the SHINE survey) only since it does request a large amount of human intervention and is not automatized yet. Note that the SHINE F150 survey is available on DIVA+ as individual observation, but also as a whole in the survey section. See the data processing page and our manual for more informations.