The macho project: Microlensing detection efficiency

C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. C. Becker, D. P. Bennett, K. H. Cook, A. J. Drake, K. C. Freeman, M. Geha, K. Griest, M. J. Lehner, S. L. Marshall, D. Minniti, C. A. Nelson, B. A. Peterson, P. Popowski, M. R. Pratt, P. J. Quinn, C. W. StubbsW. Sutherland, A. B. Tomaney, T. Vandehei, D. Welch

Resultado de la investigación: Article

32 Citas (Scopus)

Resumen

The MACHO project is a search for dark matter in the form of massive compact halo objects (MACHOs). The project has photometrically monitored over forty million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge in search of rare gravitational microlensing events caused by these otherwise invisible objects. In 5.7 yr of observations toward the LMC some 13-17 microlensing events have been observed by the MACHO survey, allowing a direct estimate of the optical depth of τ = 1.2+0.4 -0.3 × 10-7 to be measured. A critical component of this measurement is an accurate determination of the survey's detection efficiency. The detection efficiency is a complicated function of temporal sampling, stellar crowding (the luminosity function), image quality, photometry, time-series analysis, and criteria used to select the microlensing candidates. Here we describe the details of a Monte Carlo used to calculate the efficiency presented in the MACHO 5.7 yr LMC results. A similar calculation was performed for MACHO's 1 yr and 2 yr results. Several shortcomings of these past determinations are corrected, including the addition of fainter source stars, an up-to-date luminosity function for the LMC, and many other improvements. We find the MACHO detection efficiency peaks at 40%-50% for durations between 100 < t̂ < 300 days, depending upon the selection criteria employed.

Idioma originalEnglish
Páginas (desde-hasta)439-462
Número de páginas24
PublicaciónAstrophysical Journal, Supplement Series
Volumen136
N.º2
DOI
EstadoPublished - oct 2001

Huella dactilar

massive compact halo objects
Magellanic clouds
time series analysis
optical depth
luminosity
stars
galactic bulge
crowding
sampling
optical thickness
photometry
detection
project
dark matter
estimates

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Citar esto

Alcock, C., Allsman, R. A., Alves, D. R., Axelrod, T. S., Becker, A. C., Bennett, D. P., ... Welch, D. (2001). The macho project: Microlensing detection efficiency. Astrophysical Journal, Supplement Series, 136(2), 439-462. https://doi.org/10.1086/322529
Alcock, C. ; Allsman, R. A. ; Alves, D. R. ; Axelrod, T. S. ; Becker, A. C. ; Bennett, D. P. ; Cook, K. H. ; Drake, A. J. ; Freeman, K. C. ; Geha, M. ; Griest, K. ; Lehner, M. J. ; Marshall, S. L. ; Minniti, D. ; Nelson, C. A. ; Peterson, B. A. ; Popowski, P. ; Pratt, M. R. ; Quinn, P. J. ; Stubbs, C. W. ; Sutherland, W. ; Tomaney, A. B. ; Vandehei, T. ; Welch, D. / The macho project : Microlensing detection efficiency. En: Astrophysical Journal, Supplement Series. 2001 ; Vol. 136, N.º 2. pp. 439-462.
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abstract = "The MACHO project is a search for dark matter in the form of massive compact halo objects (MACHOs). The project has photometrically monitored over forty million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge in search of rare gravitational microlensing events caused by these otherwise invisible objects. In 5.7 yr of observations toward the LMC some 13-17 microlensing events have been observed by the MACHO survey, allowing a direct estimate of the optical depth of τ = 1.2+0.4 -0.3 × 10-7 to be measured. A critical component of this measurement is an accurate determination of the survey's detection efficiency. The detection efficiency is a complicated function of temporal sampling, stellar crowding (the luminosity function), image quality, photometry, time-series analysis, and criteria used to select the microlensing candidates. Here we describe the details of a Monte Carlo used to calculate the efficiency presented in the MACHO 5.7 yr LMC results. A similar calculation was performed for MACHO's 1 yr and 2 yr results. Several shortcomings of these past determinations are corrected, including the addition of fainter source stars, an up-to-date luminosity function for the LMC, and many other improvements. We find the MACHO detection efficiency peaks at 40{\%}-50{\%} for durations between 100 < t̂ < 300 days, depending upon the selection criteria employed.",
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author = "C. Alcock and Allsman, {R. A.} and Alves, {D. R.} and Axelrod, {T. S.} and Becker, {A. C.} and Bennett, {D. P.} and Cook, {K. H.} and Drake, {A. J.} and Freeman, {K. C.} and M. Geha and K. Griest and Lehner, {M. J.} and Marshall, {S. L.} and D. Minniti and Nelson, {C. A.} and Peterson, {B. A.} and P. Popowski and Pratt, {M. R.} and Quinn, {P. J.} and Stubbs, {C. W.} and W. Sutherland and Tomaney, {A. B.} and T. Vandehei and D. Welch",
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Alcock, C, Allsman, RA, Alves, DR, Axelrod, TS, Becker, AC, Bennett, DP, Cook, KH, Drake, AJ, Freeman, KC, Geha, M, Griest, K, Lehner, MJ, Marshall, SL, Minniti, D, Nelson, CA, Peterson, BA, Popowski, P, Pratt, MR, Quinn, PJ, Stubbs, CW, Sutherland, W, Tomaney, AB, Vandehei, T & Welch, D 2001, 'The macho project: Microlensing detection efficiency', Astrophysical Journal, Supplement Series, vol. 136, n.º 2, pp. 439-462. https://doi.org/10.1086/322529

The macho project : Microlensing detection efficiency. / Alcock, C.; Allsman, R. A.; Alves, D. R.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Cook, K. H.; Drake, A. J.; Freeman, K. C.; Geha, M.; Griest, K.; Lehner, M. J.; Marshall, S. L.; Minniti, D.; Nelson, C. A.; Peterson, B. A.; Popowski, P.; Pratt, M. R.; Quinn, P. J.; Stubbs, C. W.; Sutherland, W.; Tomaney, A. B.; Vandehei, T.; Welch, D.

En: Astrophysical Journal, Supplement Series, Vol. 136, N.º 2, 10.2001, p. 439-462.

Resultado de la investigación: Article

TY - JOUR

T1 - The macho project

T2 - Microlensing detection efficiency

AU - Alcock, C.

AU - Allsman, R. A.

AU - Alves, D. R.

AU - Axelrod, T. S.

AU - Becker, A. C.

AU - Bennett, D. P.

AU - Cook, K. H.

AU - Drake, A. J.

AU - Freeman, K. C.

AU - Geha, M.

AU - Griest, K.

AU - Lehner, M. J.

AU - Marshall, S. L.

AU - Minniti, D.

AU - Nelson, C. A.

AU - Peterson, B. A.

AU - Popowski, P.

AU - Pratt, M. R.

AU - Quinn, P. J.

AU - Stubbs, C. W.

AU - Sutherland, W.

AU - Tomaney, A. B.

AU - Vandehei, T.

AU - Welch, D.

PY - 2001/10

Y1 - 2001/10

N2 - The MACHO project is a search for dark matter in the form of massive compact halo objects (MACHOs). The project has photometrically monitored over forty million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge in search of rare gravitational microlensing events caused by these otherwise invisible objects. In 5.7 yr of observations toward the LMC some 13-17 microlensing events have been observed by the MACHO survey, allowing a direct estimate of the optical depth of τ = 1.2+0.4 -0.3 × 10-7 to be measured. A critical component of this measurement is an accurate determination of the survey's detection efficiency. The detection efficiency is a complicated function of temporal sampling, stellar crowding (the luminosity function), image quality, photometry, time-series analysis, and criteria used to select the microlensing candidates. Here we describe the details of a Monte Carlo used to calculate the efficiency presented in the MACHO 5.7 yr LMC results. A similar calculation was performed for MACHO's 1 yr and 2 yr results. Several shortcomings of these past determinations are corrected, including the addition of fainter source stars, an up-to-date luminosity function for the LMC, and many other improvements. We find the MACHO detection efficiency peaks at 40%-50% for durations between 100 < t̂ < 300 days, depending upon the selection criteria employed.

AB - The MACHO project is a search for dark matter in the form of massive compact halo objects (MACHOs). The project has photometrically monitored over forty million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge in search of rare gravitational microlensing events caused by these otherwise invisible objects. In 5.7 yr of observations toward the LMC some 13-17 microlensing events have been observed by the MACHO survey, allowing a direct estimate of the optical depth of τ = 1.2+0.4 -0.3 × 10-7 to be measured. A critical component of this measurement is an accurate determination of the survey's detection efficiency. The detection efficiency is a complicated function of temporal sampling, stellar crowding (the luminosity function), image quality, photometry, time-series analysis, and criteria used to select the microlensing candidates. Here we describe the details of a Monte Carlo used to calculate the efficiency presented in the MACHO 5.7 yr LMC results. A similar calculation was performed for MACHO's 1 yr and 2 yr results. Several shortcomings of these past determinations are corrected, including the addition of fainter source stars, an up-to-date luminosity function for the LMC, and many other improvements. We find the MACHO detection efficiency peaks at 40%-50% for durations between 100 < t̂ < 300 days, depending upon the selection criteria employed.

KW - Dark matter

KW - Gravitational lensing

KW - Methods: data analysis

KW - Stars: low-mass, brown dwarfs

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U2 - 10.1086/322529

DO - 10.1086/322529

M3 - Article

AN - SCOPUS:18044365673

VL - 136

SP - 439

EP - 462

JO - Astrophysical Journal, Supplement Series

JF - Astrophysical Journal, Supplement Series

SN - 0067-0049

IS - 2

ER -

Alcock C, Allsman RA, Alves DR, Axelrod TS, Becker AC, Bennett DP y otros. The macho project: Microlensing detection efficiency. Astrophysical Journal, Supplement Series. 2001 oct;136(2):439-462. https://doi.org/10.1086/322529