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arXiv · 2509.08044

spherical: A Comprehensive Database and Automated Pipeline for VLT/SPHERE High-Contrast Imaging

Matthias Samland
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Abstract

I present spherical (https://github.com/m-samland/spherical), a software package and database designed for the ESO VLT/SPHERE high-contrast imager. SPHERE has produced the world's largest archive of direct imaging observations of exoplanets and circumstellar disks, but its heterogeneous metadata and fragmented reduction tools make end-to-end analysis labor-intensive. spherical addresses this by combining (1) a curated, regularly updated, and searchable database of all SPHERE observations, cross-matched with stellar properties and observing conditions, and (2) a Python-based, script-driven pipeline for the Integral Field Spectrograph (IFS). The database, archived on Zenodo (https://doi.org/10.5281/zenodo.15147730) and reproducible from the ESO archive, currently includes about 6000 IRDIS dual-band imaging, about 1000 IRDIS polarimetric, and about 4500 IFS sequences, with additional modes (ZIMPOL, IRDIS-LSS, SAM) planned. The pipeline automates raw data retrieval, calibration, and IFS reduction with the adapted open-source CHARIS instrument pipeline, followed by astrometric and photometric calibration and post-processing with TRAP for companion detection and spectral extraction. spherical lowers the barrier from raw files to science-ready products, enabling homogeneous population studies, atmospheric characterization of companions, and efficient survey follow-up, while remaining interoperable with community tools such as VIP, pyKLIP, and IRDAP.

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Matthias Samland. 2025-09-09. spherical: A Comprehensive Database and Automated Pipeline for VLT/SPHERE High-Contrast Imaging. https://arxiv.org/abs/2509.08044

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