Variable stars towards the bulge of M 31: The AGAPE catalogue

• Published in: Astronomy and astrophysics (Berlin) 2004-07, Vol.421 (2), p.509-518
• Main Authors: Ansari, R., Aurière, M., Baillon, P., Bouquet, A., Coupinot, G., Coutures, Ch, Ghesquière, C., Giraud-Héraud, Y., Gillieron, D., Gondolo, P., Hecquet, J., Kaplan, J., Kim, A., Le Du, Y., Melchior, A. L., Moniez, M., Picat, J. P., Soucail, G.
• Format: Article
• Language: English
• Subjects: cataclysmic variables; cosmology: dark matter; galaxies: individual: M 31; stars: novae; stars: variables: Cepheids; stars: variables: general; X-rays: stars
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361:20035659

We present the AGAPE astrometric and photometric catalogue of 1579 variable stars in a $14'$ $\times$ $10'$ field centred on M 31. This work is the first survey devoted to variable stars in the bulge of M 31. The R magnitudes of the objects and the $B-R$ colours suggest that our sample is dominated by red long-period variable stars (LPV), with a possible overlap with Cepheid-like type II stars. Fits of the light curves with sinusoids suggest that a large fraction of the stars correspond to periodic or semi-periodic objects with periods longer than 100 days. Twelve nova candidates are identified. Correlations with other catalogues suggest that 2 novae could be recurrent novae and provide possible optical counterparts for 2 supersoft X-ray sources candidates observed with Chandra.