Issue A&A Volume 469, Number 1, July I 2007 Page(s) 115 - 119 Section Extragalactic astronomy DOI 10.1051/0004-6361:20077075

A&A 469, 115-119 (2007)
DOI: 10.1051/0004-6361:20077075

Probing MACHOs by observation of M 31 pixel lensing with the 1.5 m Loiano telescope

S. Calchi Novati^{1, 2}, G. Covone³, F. De Paolis⁴, M. Dominik⁵, Y. Giraud-Héraud⁶, G. Ingrosso⁴, Ph. Jetzer⁷, L. Mancini^{1, 2}, A. Nucita⁴, G. Scarpetta^{1, 2}, F. Strafella⁴, and A. Gould<sup>8

1</sup>  Dipartimento di Fisica "E. R. Caianiello", Università di Salerno, via S. Allende, 84081 Baronissi (SA), Italy
    e-mail: novati@sa.infn.it
²  Istituto Nazionale di Fisica Nucleare, sezione di Napoli, Italy
³  INAF - Osservatorio Astronomico di Capodimonte, via Moiariello 16, Napoli, Italy
⁴  Dipartimento di Fisica, Università di Lecce and INFN, Sezione di Lecce, CP 193, 73100 Lecce, Italy
⁵  SUPA, University of St Andrews, School of Physics & Astronomy, North Haugh, St Andrews, KY16 9SS, UK
⁶  APC, 10, rue Alice Domon et Léonie Duquet 75205 Paris, France
⁷  Institute for Theoretical Physics, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
⁸  Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, US

(Received 10 January 2007 / Accepted 29 March 2007)

Abstract
We analyse a series of pilot observations in order to study microlensing of (unresolved) stars in M 31 with the 1.5 m Loiano telescope, including observations on both identified variable source stars and reported microlensing events. We also look for previously unknown variability and discover a nova. We discuss an observing strategy for an extended campaign with the goal of determining whether MACHOs exist or whether all microlensing events are compatible with lens stars in M 31.

Key words: gravitational lensing -- Galaxy: Halo -- galaxies: individual: M 31

© ESO 2007

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