Improving transit detection with collective light curves information

Abstract

The search for planetary transits in star light-curves can be improved in an non standard way applying appropriate filtering of the systematic effects just after the detection step. The procedure has been tested using a set of light curves simulated in the context of the CoRoT space mission. The level of the continuum in the detection curves is significantly lowered when compared to other standard approaches, a property we use to reduce false alarm. Ambiguities may originate in unexpected effects that combine instrumental and environmental factors. In a large set of synchronous light curves collective behaviours permit to identify systematic effects against which the detected events are compared. We estimate a significance of our detections and show that with our procedure the number of true detections is increased by more than 80% (22 events detected over the 36 injected ones). In spite of its simplicity, our method scores quite well (average results) when compared to the other methods used for the CoRoT blind test exercice by Moutou et al. 1