Journal
ASTRONOMY & ASTROPHYSICS
Volume 530, Issue -, Pages -Publisher
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201016324
Keywords
stars: early-type; subdwarfs; astronomical databases: miscellaneous; Virtual Observatory tools
Categories
Funding
- Spanish MEC [AyA2008-02156]
- Spanish Ministry of Science and Innovation (MICINN) [AYA 2009-14648-02]
- Xunta de Galicia [INCITE09 E1R312096ES, INCITE09 312191PR]
- E.U.
- Department of Physics and Astronomy of the University of Delaware
- European Research Council under the European Community [227224]
- Council of K.U. Leuven [FOA/2008/04]
Ask authors/readers for more resources
Context. Recent massive sky surveys in different bandwidths are providing new opportunities to modern astronomy. The Virtual Observatory (VO) provides the adequate framework to handle the huge amount of information available and filter out data according to specific requirements. Aims. Hot subdwarf stars are faint, blue objects, and are the main contributors to the far-UV excess observed in elliptical galaxies. They offer an excellent laboratory to study close and wide binary systems, and to scrutinize their interiors through asteroseismology, since some of them undergo stellar oscillations. However, their origins are still uncertain, and increasing the number of detections is crucial to undertake statistical studies. In this work, we aim at defining a strategy to find new, uncatalogued hot subdwarfs. Methods. Making use of VO tools we thoroughly search stellar catalogues to retrieve multi-colour photometry and astrometric information of a known sample of blue objects, including hot subdwarfs, white dwarfs, cataclysmic variables and main-sequence OB stars. We define a procedure to distinguish among these spectral classes, which is particularly designed to obtain a hot subdwarf sample with a low contamination factor. To check the validity of the method, this procedure is then applied to two test sky regions: to the Kepler FoV and to a test region of 300 deg(2) around (alpha:225, delta:5) deg. Results. As a result of the procedure we obtained 38 hot subdwarf candidates, 23 of which had already a spectral classification. We have acquired spectroscopy for three other targets, and four additional ones have an available SDSS spectrum, which we used to determine their spectral type. A temperature estimate is provided for the candidates based on their spectral energy distribution, considering two-atmospheres fit for objects with clear infrared excess as a signature of the presence of a cool companion. Eventually, out of 30 candidates with spectral classification, 26 objects were confirmed to be hot subdwarfs, which means a contamination factor of only 13%. The high rate of success demonstrates the validity of the proposed strategy to find new uncatalogued hot subdwarfs. An application of this method to the entire sky will be presented in a forthcoming work.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available