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Context.
The ESA
Euclid
space telescope could observe up to 150 000 asteroids as a side product of its primary cosmological mission. Asteroids appear as trailed sources, that is streaks, in the images. Owing to the survey area of 15 000 square degrees and the number of sources, automated methods have to be used to find them.
Euclid
is equipped with a visible camera, VIS (VISual imager), and a near-infrared camera, NISP (Near-Infrared Spectrometer and Photometer), with three filters.
Aims.
We aim to develop a pipeline to detect fast-moving objects in
Euclid
images, with both high completeness and high purity.
Methods.
We tested the
StreakDet
software to find asteroids from simulated
Euclid
images. We optimized the parameters of
StreakDet
to maximize completeness, and developed a post-processing algorithm to improve the purity of the sample of detected sources by removing false-positive detections.
Results.
StreakDet
finds 96.9% of the synthetic asteroid streaks with apparent magnitudes brighter than 23rd magnitude and streak lengths longer than 15 pixels (10 arcsec h
−1
), but this comes at the cost of finding a high number of false positives. The number of false positives can be radically reduced with multi-streak analysis, which utilizes all four dithers obtained by
Euclid
.
Conclusions.
StreakDet
is a good tool for identifying asteroids in
Euclid
images, but there is still room for improvement, in particular, for finding short (less than 13 pixels, corresponding to 8 arcsec h
−1
) and/or faint streaks (fainter than the apparent magnitude of 23).