Detection system

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Detailed description (in draft version) of the Java code is available from Gaia WebSVN (Gaia password required), or here.


Detection will be conducted in almost entire range of available magnitudes from Gaia. Limiting magnitude for Gaia is equivalent of V=20mag, but for detection we will require signal above at least 19mag, to avoid spurious anomalies at high noise level. The saturation limit for Gaia is around 5 mag.

  • Detection system employs the following data:
    • G-flux observations - all available in given cycle
    • accumulated G-flux: mean and scatter
    • accumulated BP and RP colours
    • low-dispersion BP and RP spectrometry
    • morphology of the source
    • source motion flags
    • later in the mission: CU3, CU4, CU7 and CU8’s deliverables (information on motion, variability, astrophysical parameters)

Sampling properties of Gaia

Number of observations per source over entire mission.

Detections will be strongly affected by sampling properties of the Gaia. These are induced by characteristic "scanning law" (see figure).

Photometric precision

Photometric precision.png From M. Varadi et al. 2009.


At this stage all additional information from Gaia and later from other catalogues will be used for narrowing down the sample of interesting alerts.

Cross-matching with existing catalogues

List of catalogues to cross-match