Population-based identification of H α-excess sources in the Gaia DR2 and IPHAS catalogues

Fratta, M; Scaringi, S; Drew, JE; Monguió, M; Knigge, C; Maccarone, TJ; Court, JMC; Iłkiewicz, KA; Pala, AF; Gandhi, P; Gänsicke, B

Abstract

We present a catalogue of point-like H α-excess sources in the Northern Galactic Plane. Our catalogue is created using a new technique that leverages astrometric and photomeric information from Gaia to select H α-bright outliers in the INT Photometric H α Survey of the Northern Galactic Plane (IPHAS), across the colour–absolute magnitude diagram. To mitigate the selection biases due to stellar population mixing and to extinction, the investigated objects are first partitioned with respect to their positions in the Gaia colour–absolute magnitude space, and Galactic coordinates space, respectively. The selection is then performed on both partition types independently. Two significance parameters are assigned to each target, one for each partition type. These represent a quantitative degree of confidence that the given source is a reliable H α-excess candidate, with reference to the other objects in the corresponding partition. Our catalogue provides two flags for each source, both indicating the significance level of the H α-excess. By analysing their intensity in the H α narrow band, 28 496 objects out of 7474 835 are identified as H α-excess candidates with a significance higher than 3. The completeness fraction of the H α outliers selection is between 3 and 5 per cent. The suggested 5σ conservative cut yields a purity fraction of 81.9 per cent.

Citation

Fratta, M., Scaringi, S., Drew, J., Monguió, M., Knigge, C., Maccarone, T., Court, J., Iłkiewicz, K., Pala, A., Gandhi, P., & Gänsicke, B. (2021). Population-based identification of H α-excess sources in the Gaia DR2 and IPHAS catalogues. Monthly Notices of the Royal Astronomical Society, 505(1), 1135-1152. https://doi.org/10.1093/mnras/stab1258

• Journal Article Type: Article
• Acceptance Date: Apr 27, 2021
• Online Publication Date: May 21, 2021
• Publication Date: 2021-07
• Deposit Date: Aug 18, 2021
• Publicly Available Date: Aug 19, 2021
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 505
• Issue: 1
• Pages: 1135-1152
• DOI: https://doi.org/10.1093/mnras/stab1258
• Public URL: https://durham-repository.worktribe.com/output/1243723