Sign on

SAO/NASA ADS Astronomy Abstract Service


· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:astro-ph/9907369)
· References in the article
· Citations to the Article (106) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (21)
· NED Objects (2)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Binary Microlensing Events from the MACHO Project
Authors:
Alcock, C.; Allsman, R. A.; Alves, D.; Axelrod, T. S.; Baines, D.; Becker, A. C.; Bennett, D. P.; Bourke, A.; Brakel, A.; Cook, K. H.; Crook, B.; Crouch, A.; Dan, J.; Drake, A. J.; Fragile, P. C.; Freeman, K. C.; Gal-Yam, A.; Geha, M.; Gray, J.; Griest, K.; Gurtierrez, A.; Heller, A.; Howard, J.; Johnson, B. R.; Kaspi, S.; Keane, M.; Kovo, O.; Leach, C.; Leach, T.; Leibowitz, E. M.; Lehner, M. J.; Lipkin, Y.; Maoz, D.; Marshall, S. L.; McDowell, D.; McKeown, S.; Mendelson, H.; Messenger, B.; Minniti, D.; Nelson, C.; Peterson, B. A.; Popowski, P.; Pozza, E.; Purcell, P.; Pratt, M. R.; Quinn, J.; Quinn, P. J.; Rhie, S. H.; Rodgers, A. W.; Salmon, A.; Shemmer, O.; Stetson, P.; Stubbs, C. W.; Sutherland, W.; Thomson, S.; Tomaney, A.; Vandehei, T.; Walker, A.; Ward, K.; Wyper, G.
Affiliation:
AA(Lawrence Livermore National Laboratory, Livermore, CA 94550.; Center for Particle Astrophysics, University of California, Berkeley, Berkeley, CA 94720), AB(Supercomputing Facility, Australian National University, Canberra, ACT 0200, Australia), AC(Lawrence Livermore National Laboratory, Livermore, CA 94550.; Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218), AD(Mt. Stromlo and Siding Spring Observatories, Australian National University, Weston, ACT 2611, Australia), AE(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), AF(Center for Particle Astrophysics, University of California, Berkeley, Berkeley, CA 94720.; Departments of Astronomy and Physics, University of Washington, Seattle, WA 98195), AG(Lawrence Livermore National Laboratory, Livermore, CA 94550.; Center for Particle Astrophysics, University of California, Berkeley, Berkeley, CA 94720.; Department of Physics, University of Notre Dame, Notre Dame, IN 46556), AH(Department of Mathematics and Statistics, Monash University, Clayton, Victoria, 3168, Australia), AI(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), AJ(Lawrence Livermore National Laboratory, Livermore, CA 94550), AK(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), AL(Department of Mathematics and Statistics, Monash University, Clayton, Victoria, 3168, Australia), AM(School of Physics & Astronomy and Wise Observatory, Tel-Aviv University, Tel-Aviv 69978, Israel), AN(Mt. Stromlo and Siding Spring Observatories, Australian National University, Weston, ACT 2611, Australia), AO(Department of Physics, University of Notre Dame, Notre Dame, IN 46556), AP(Mt. Stromlo and Siding Spring Observatories, Australian National University, Weston, ACT 2611, Australia), AQ(School of Physics & Astronomy and Wise Observatory, Tel-Aviv University, Tel-Aviv 69978, Israel), AR(Lawrence Livermore National Laboratory, Livermore, CA 94550.; Department of Physics, University of California, Davis, Davis, CA 92093), AS(Department of Mathematics and Statistics, Monash University, Clayton, Victoria, 3168, Australia), AT(Center for Particle Astrophysics, University of California, Berkeley, Berkeley, CA 94720.; Department of Physics, University of California, San Diego, San Diego, CA 92093), AU(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), AV(School of Physics & Astronomy and Wise Observatory, Tel-Aviv University, Tel-Aviv 69978, Israel), AW(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), AX(Tate Laboratory of Physics, University of Minnesota, Minneapolis, MN 55455), AY(School of Physics & Astronomy and Wise Observatory, Tel-Aviv University, Tel-Aviv 69978, Israel), AZ(Cerro Tololo Interamerican Observatory, National Optical Astronomy Observatories), BA(School of Physics & Astronomy and Wise Observatory, Tel-Aviv University, Tel-Aviv 69978, Israel), BB(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), BC(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), BD(School of Physics & Astronomy and Wise Observatory, Tel-Aviv University, Tel-Aviv 69978, Israel), BE(Department of Physics, University of Sheffield, Sheffield s3 7RH, UK), BF(School of Physics & Astronomy and Wise Observatory, Tel-Aviv University, Tel-Aviv 69978, Israel), BG(School of Physics & Astronomy and Wise Observatory, Tel-Aviv University, Tel-Aviv 69978, Israel), BH(Lawrence Livermore National Laboratory, Livermore, CA 94550), BI(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), BJ(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), BK(School of Physics & Astronomy and Wise Observatory, Tel-Aviv University, Tel-Aviv 69978, Israel), BL(Department of Mathematics and Statistics, Monash University, Clayton, Victoria, 3168, Australia), BM(Lawrence Livermore National Laboratory, Livermore, CA 94550.; Departmento de Astronomia, P. Universidad Católica, Casilla 104, Santiago 22, Chile), BN(Lawrence Livermore National Laboratory, Livermore, CA 94550.; Department of Physics, University of California, Berkeley, Berkeley, CA 92093), BO(Mt. Stromlo and Siding Spring Observatories, Australian National University, Weston, ACT 2611, Australia), BP(Lawrence Livermore National Laboratory, Livermore, CA 94550), BQ(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), BR(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), BS(Center for Particle Astrophysics, University of California, Berkeley, Berkeley, CA 94720.; Center for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139), BT(Department of Physics, University of Notre Dame, Notre Dame, IN 46556), BU(European Southern Observatory, Karl-Schwarzschild Strasse 2, D-85748, Garching, Germany), BV(Department of Physics, University of Notre Dame, Notre Dame, IN 46556), BW(Mt. Stromlo and Siding Spring Observatories, Australian National University, Weston, ACT 2611, Australia), BX(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), BY(School of Physics & Astronomy and Wise Observatory, Tel-Aviv University, Tel-Aviv 69978, Israel), BZ(National Research Council, 5071 West Saanich Road, RR 5, Victoria, BC V8X 4M6, Canada), CA(Center for Particle Astrophysics, University of California, Berkeley, Berkeley, CA 94720.; Departments of Astronomy and Physics, University of Washington, Seattle, WA 98195), CB(Department of Physics, University of Oxford, Oxford OX1 3RH, UK), CC(Department of Mathematics and Statistics, Monash University, Clayton, Victoria, 3168, Australia), CD(Departments of Astronomy and Physics, University of Washington, Seattle, WA 98195), CE(Center for Particle Astrophysics, University of California, Berkeley, Berkeley, CA 94720.; Department of Physics, University of California, San Diego, San Diego, CA 92093), CF(Cerro Tololo Interamerican Observatory, National Optical Astronomy Observatories), CG(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia), CH(Reynolds Amateur Photometry Team, Canberra Astronomical Society, Canberra, ACT 0200, Australia)
Publication:
The Astrophysical Journal, Volume 541, Issue 1, pp. 270-297. (ApJ Homepage)
Publication Date:
09/2000
Origin:
UCP
ApJ Keywords:
Stars: Binaries: General, Cosmology: Dark Matter, Cosmology: Gravitational Lensing, Stars: Low-Mass, Brown Dwarfs
DOI:
10.1086/309393
Bibliographic Code:
2000ApJ...541..270A

Abstract

We present the light curves of 21 gravitational microlensing events from the first six years of the MACHO Project gravitational microlensing survey that are likely examples of lensing by binary systems. These events were manually selected from a total sample of ~350 candidate microlensing events that were either detected by the MACHO Alert System or discovered through retrospective analyses of the MACHO database. At least 14 of these 21 events exhibit strong (caustic) features, and four of the events are well fit with lensing by large mass ratio (brown dwarf or planetary) systems, although these fits are not necessarily unique. The total binary event rate is roughly consistent with predictions based upon our knowledge of the properties of binary stars, but a precise comparison cannot be made without a determination of our binary lens event detection efficiency. Toward the Galactic bulge, we find a ratio of caustic crossing to noncaustic crossing binary lensing events of 12:4, excluding one event for which we present two fits. This suggests significant incompleteness in our ability to detect and characterize noncaustic crossing binary lensing. The distribution of mass ratios, N(q), for these binary lenses appears relatively flat. We are also able to reliably measure source-face crossing times in four of the bulge caustic crossing events, and recover from them a distribution of lens proper motions, masses, and distances consistent with a population of Galactic bulge lenses at a distance of 7+/-1 kpc. This analysis yields two systems with companions of ~0.05 Msolar.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints