Search for exoplanets in M31 with pixel-lensing and the PA-99-N2 event revisited

• DOI: 10.1007/s10714-010-0942-3
• Publication Date: 2010-03-03T18:07:40Z
• Authors: Gabriele Ingrosso; Sebastiano Calchi...; Francesco De Paolis; Philippe Jetzer; Achille Nucita; Alexander Zakharov
• Keywords: Earth and Planetary Astrophysics (astro-ph.EP); 530 Physics; Microlensing; Exoplanets; Spiral galaxies: M31; FOS: Physical sciences; 10231 Institute of Theoretical Astrophysics and Cosmology; 01 natural sciences; Astrophysics - Solar and Stellar Astrophysics; 0103 physical sciences; 3101 Physics and Astronomy (miscellaneous); Exoplanets, Microlensing, Spiral galaxies: M31; Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics - Earth and Planetary Astrophysics

Several exoplanets have been detected towards the Galactic bulge with the microlensing technique. We show that exoplanets in M31 may also be detected with the pixel-lensing method, if telescopes making high cadence observations of an ongoing microlensing event are used. Using a Monte Carlo approach we find that the mean mass for detectable planetary systems is about $2 M_{\rm {J}}$. However, even small mass exoplanets ($M_{\rm P} < 20 M_{\oplus}$) can cause significant deviations, which are observable with large telescopes. We reanalysed the POINT-AGAPE microlensing event PA-99-N2. First, we test the robustness of the binary lens conclusion for this light curve. Second, we show that for such long duration and bright microlensing events, the efficiency for finding planetary-like deviations is strongly enhanced with respect to that evaluated for all planetary detectable events.<br/>14 pages, 8 figures. Paper presented at the "II Italian-Pakistani Workshop on Relativistic Astrophysics, Pescara, July 8-10, 2009. To be published in a special issue of General Relativity and Gravitation (eds. F. De Paolis, G.F.R. Ellis, A. Qadir and R. Ruffini)<br/>