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

S.C. Novati; S. Paulin-Henriksson; J. An; P. Baillon; V. Belokurov; B.J. Carr; M. Creze; N.W. Evans; Y. Giraud- Heraud; A. Gould; P. Hewett; P. Jetzer; J. Kaplan; E. Kerins; Stephen Smartt; C.S. Stalin; Y. Tsapras; M.J. Weston

doi:10.1051/0004-6361:20053135

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

S.C. Novati, S. Paulin-Henriksson, J. An, P. Baillon, V. Belokurov, B.J. Carr, M. Creze, N.W. Evans, Y. Giraud- Heraud, A. Gould, P. Hewett, P. Jetzer, J. Kaplan, E. Kerins, Stephen Smartt, C.S. Stalin, Y. Tsapras, M.J. Weston

Research output: Contribution to journal › Article › peer-review

80 Citations (Scopus)

Abstract

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.

Original language	English
Pages (from-to)	911-928
Number of pages	18
Journal	Astronomy and Astrophysics
Volume	443
Issue number	3
DOIs	https://doi.org/10.1051/0004-6361:20053135
Publication status	Published - Dec 2005

ASJC Scopus subject areas

Space and Planetary Science

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Novati, S. C., Paulin-Henriksson, S., An, J., Baillon, P., Belokurov, V., Carr, B. J., Creze, M., Evans, N. W., Giraud- Heraud, Y., Gould, A., Hewett, P., Jetzer, P., Kaplan, J., Kerins, E., Smartt, S., Stalin, C. S., Tsapras, Y., & Weston, M. J. (2005). POINT-AGAPE pixel lensing survey of M31 - Evidence for a MACHO contribution to galactic halos. Astronomy and Astrophysics, 443(3), 911-928. https://doi.org/10.1051/0004-6361:20053135

Novati, S.C. ; Paulin-Henriksson, S. ; An, J. ; Baillon, P. ; Belokurov, V. ; Carr, B.J. ; Creze, M. ; Evans, N.W. ; Giraud- Heraud, Y. ; Gould, A. ; Hewett, P. ; Jetzer, P. ; Kaplan, J. ; Kerins, E. ; Smartt, Stephen ; Stalin, C.S. ; Tsapras, Y. ; Weston, M.J. / POINT-AGAPE pixel lensing survey of M31 - Evidence for a MACHO contribution to galactic halos. In: Astronomy and Astrophysics. 2005 ; Vol. 443, No. 3. pp. 911-928.

@article{612963cfb7f24196b66893b0b5a3e29e,

title = "POINT-AGAPE pixel lensing survey of M31 - Evidence for a MACHO contribution to galactic halos",

abstract = "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.",

author = "S.C. Novati and S. Paulin-Henriksson and J. An and P. Baillon and V. Belokurov and B.J. Carr and M. Creze and N.W. Evans and {Giraud- Heraud}, Y. and A. Gould and P. Hewett and P. Jetzer and J. Kaplan and E. Kerins and Stephen Smartt and C.S. Stalin and Y. Tsapras and M.J. Weston",

year = "2005",

month = dec,

doi = "10.1051/0004-6361:20053135",

language = "English",

volume = "443",

pages = "911--928",

journal = "Astronomy and Astrophysics",

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Novati, SC, Paulin-Henriksson, S, An, J, Baillon, P, Belokurov, V, Carr, BJ, Creze, M, Evans, NW, Giraud- Heraud, Y, Gould, A, Hewett, P, Jetzer, P, Kaplan, J, Kerins, E, Smartt, S, Stalin, CS, Tsapras, Y & Weston, MJ 2005, 'POINT-AGAPE pixel lensing survey of M31 - Evidence for a MACHO contribution to galactic halos', Astronomy and Astrophysics, vol. 443, no. 3, pp. 911-928. https://doi.org/10.1051/0004-6361:20053135

POINT-AGAPE pixel lensing survey of M31 - Evidence for a MACHO contribution to galactic halos. / Novati, S.C.; Paulin-Henriksson, S.; An, J.; Baillon, P.; Belokurov, V.; Carr, B.J.; Creze, M.; Evans, N.W.; Giraud- Heraud, Y.; Gould, A.; Hewett, P.; Jetzer, P.; Kaplan, J.; Kerins, E.; Smartt, Stephen; Stalin, C.S.; Tsapras, Y.; Weston, M.J.

In: Astronomy and Astrophysics, Vol. 443, No. 3, 12.2005, p. 911-928.

Research output: Contribution to journal › Article › peer-review

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 -