Details

Autor(en) / Beteiligte

• CALCHI NOVATI, S
• PAULIN-HENRIKSSON, S
• HEWETT, P
• JETZER, Ph
• KAPLAN, J
• KERINS, E
• SMARTT, S. J
• STALIN, C. S
• TSAPRAS, Y
• WESTON, M. J
• AN, J
• BAILLON, P
• BELOKUROV, V
• CARR, B. J
• CREZE, M
• EVANS, N. W
• GIRAUD-HERAUD, Y
• GOULD, A

Titel

POINT-AGAPE pixel lensing survey of M31 : Evidence for a MACHO contribution to galactic halos

Ist Teil von

• Astronomy and astrophysics (Berlin), 2005-12, Vol.443 (3), p.911-928

Ort / Verlag

Les Ulis: EDP Sciences

Erscheinungsjahr

2005

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• The POINT-AGAPE collaboration is carrying out a search for gravitational microlensing toward M31 to reveal galactic dark matter in the form of MACHOs (Massive Astrophysical Compact Halo Objects) in the halos of the Milky Way and M31. A high-threshold analysis of 3 years of data yields 6 bright, short-duration microlensing events, which are confronted to a simulation of the observations and the analysis. The observed signal is much larger than expected from self lensing alone and we conclude, at the 95% confidence level, that at least 20% of the halo mass in the direction of M31 must be in the form of MACHOs if their average mass lies in the range 0.5-1 M. This lower bound drops to 8% for MACHOs with masses 60.01 M. In addition, we discuss a likely binary microlensing candidate with caustic crossing. Its location, some 32' away from the centre of M31, supports our conclusion that we are detecting a MACHO signal in the direction of M31.