Calibration of the MACHO photometry database

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, B. A. Peterson, P. Popowski, M. R. Pratt, C. A. Nelson, P. J. Quinn, C. W. StubbsW. Sutherland, A. B. Tomaney, T. Vandehei, D. L. Welch

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

114 Citas (Scopus)


The MACHO Project is a microlensing survey that monitors the brightnesses of ∼60 million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and Galactic bulge. Our database presently contains about 80 billion photometric measurements, a significant fraction of all astronomical photometry. We describe the calibration of MACHO two-color photometry and transformation to the standard Kron-Cousins V and R system. Calibrated MACHO photometry may be properly compared with all other observations on the Kron-Cousins standard system, enhancing the astrophysical value of these data. For ∼9 million stars in the LMC bar, independent photometric measurements of ∼20,000 stars with V ≲ 18 mag in field-overlap regions demonstrate an internal precision σV = 0.021, σR = 0.019, σV-R = 0.028 mag. The accuracy of the zero point in this calibration is estimated to be ±0.035 mag for stars with colors in the range -0.1 mag < V - R < 1.2 mag. A comparison of calibrated MACHO photometry with published photometric sequences and new Hubble Space Telescope observations shows agreement. The current calibration zero-point uncertainty for the remainder of the MACHO photometry database is estimated to be ±0.10 mag in V or R and ±0.04 mag in V - R. We describe the first application of calibrated MACHO data: the construction of a color-magnitude diagram used to calculate our experimental sensitivity for detecting microlensing in the LMC.

Idioma originalInglés
Páginas (desde-hasta)1539-1558
Número de páginas20
PublicaciónPublications of the Astronomical Society of the Pacific
EstadoPublicada - dic 1999

Áreas temáticas de ASJC Scopus

  • Astronomía y astrofísica
  • Ciencias planetarias y espacial


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