Microlensing search towards M31
Abstract
We present the first results of the analysis of data collected during the 1998-99 observational campaign at the 1.3 meter McGraw-Hill Telescope, towards the Andromeda galaxy (M31), aimed to the detection of gravitational microlensing effects as a probe of the presence of dark matter in our and in M31 halo. The analysis is performed using the pixel lensing technique, which consists in the study of flux variations of unresolved sources and has been proposed and implemented by the AGAPE collaboration. We carry out a shape analysis by demanding that the detected flux variations be achromatic and compatible with a Paczynski light curve. We apply the Durbin-Watson hypothesis test to the residuals. Furthermore, we consider the background of variables sources. Finally five candidate microlensing events emerge from our selection. Comparing with the predictions of a Monte Carlo simulation, assuming a standard spherical model for the M31 and Galactic haloes, and typical values for the MACHO mass, we find that our events are only marginally consistent with the distribution of observable parameters predicted by the simulation.
Cite
@article{arxiv.astro-ph/0110706,
title = {Microlensing search towards M31},
author = {S. Calchi Novati and G. Iovane and A. A. Marino and M. Auriere and P. Baillon and A. Bouquet and V. Bozza and M. Capaccioli and S. Capozziello and V. Cardone and G. Covone and F. De Paolis and R. de Ritis and Y. Giraud-Heraud and A. Gould and G. Ingrosso and Ph. Jetzer and J. Kaplan and G. Lambiase and Y. Le Du and L. Mancini and E. Piedipalumbo and V. Re and M. Roncadelli and C. Rubano and G. Scarpetta and P. Scudellaro and M. Sereno and F. Strafella},
journal= {arXiv preprint arXiv:astro-ph/0110706},
year = {2009}
}
Comments
13 pages, To appear in A&A