TY - JOUR
T1 - POINT-AGAPE pixel lensing survey of M31 - Evidence for a MACHO contribution to galactic halos
AU - Novati, S.C.
AU - Paulin-Henriksson, S.
AU - An, J.
AU - Baillon, P.
AU - Belokurov, V.
AU - Carr, B.J.
AU - Creze, M.
AU - Evans, N.W.
AU - Giraud- Heraud, Y.
AU - Gould, A.
AU - Hewett, P.
AU - Jetzer, P.
AU - Kaplan, J.
AU - Kerins, E.
AU - Smartt, Stephen
AU - Stalin, C.S.
AU - Tsapras, Y.
AU - Weston, M.J.
PY - 2005/12
Y1 - 2005/12
N2 - 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-circle dot. This lower bound drops to 8% for MACHOs with masses similar to 0.01 M-circle dot. 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.
AB - 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-circle dot. This lower bound drops to 8% for MACHOs with masses similar to 0.01 M-circle dot. 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.
U2 - 10.1051/0004-6361:20053135
DO - 10.1051/0004-6361:20053135
M3 - Article
VL - 443
SP - 911
EP - 928
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
IS - 3
ER -