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Objectives of SPHERE-DC

by Administrateur - 7 January 2015 ( maj : 5 October 2016 )


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). The conception of SPHERE has therefore been driven by the necessity to obtain the highest possible contrast in the immediate environment of the stars. To do that, SPHERE combine several advanced techniques (extreme adaptive optics, coronography, differential imager and spectro-imager in the visible and near infrared). SPHERE 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). These instruments produce huge amounts of data (large volume and diversity) requiring specific data processing to produce the desired high contrast, to take advantage the performances of the instruments in terms of detection and characterization of the astrophysical signal.
We have implemented a Data Center allowing to answer this need, constituting a reference center on high contrast. The objective is to gather the high contrast imaging community to optimize the scientific return on SPHERE. This service will bring a strong added-value to the data obtained with SPHERE by providing optimized tools.


The four observatories partners of SPHERE-DC are :

  • Observatoire des Sciences de l’Univers de Grenoble (OSUG) / Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
  • Observatoire de la Côte d’Azur (OCA) / Lagrange
  • PYTHEAS / Laboratoire d’Astrophysique de Marseille
  • Observatoire de Paris / Laboratoire d’études spatiales et d’instrumentation en astrophysique (LESIA)

The two components of SPHERE-DC:

  • The processing center (CT), hosted in Grenoble. The CT have several functionalities: SPHERE data processing on request, support to process surveys, instrument monitoring, reduced calibrations and later processed data diffusion (including a reprocessing of all SPHERE data to constituted a SPHERE Legacy catalogue).
  • The Target Data Base (TDB), hosted in Marseille. The Target Data Base provides a catalogue of star physical properties (today, for the SPHERE consortium survey), observing conditions, detection and non-detections and properties ; reduced data from instruments other than SPHERE (DIVA archive).

Local infrastructures

The project relies on local infrastructures (which includes other services and projects), which ensures the long-term maintenance of the development being made and allows expertise sharing with other projects: in Grenoble, SPHERE-DC is part of the OSUG-DC Data Center and relies on the Université Grenoble Alpes infrastructures; in Marseille SPHERE-DC is developed by the CeSAM.