Binary microlensing events from the MACHO project

  title={Binary microlensing events from the MACHO project},
  author={Charles R. Alcock and Robyn A. Allsman and David Randall Alves and Timothy S. Axelrod and Deborah Baines and Andrew Cameron Becker and David P. Bennett and Adam J. Bourke and A. T. Brakel and K. H. Cook and B. Crook and Ashley D. Crouch and J. Dan and Andrew J. Drake and P. Chris Fragile and Kenneth C. Freeman and Avishay Gal-yam and Marla Geha and Jerry Gray and Kim Griest and A. Gurtierrez and Ana B. Heller and J. Howard and Bradley R. Johnson and Shai Kaspi and Michael J. Keane and Orly Kovo and C. M. Leach and T. Leach and Elia Leibowitz and Matthew J. Lehner and Y. M. Lipkin and Dan Maoz and Simon L. Marshall and D. McDowell and Steven Mckeown and Haim Mendelson and B. B. Messenger and Dante Minniti and Cailin Anne Nelson and Bruce A. Peterson and Piotr Popowski and Enrico Pozza and Patrick N. Purcell and Mark Robin Pratt and J. L. Quinn and Peter Quinn and Sun Hong Rhie and Alex W. Rodgers and Alex Salmon and Ohad Shemmer and Peter B. Stetson and Christopher W. Stubbs and William J. Sutherland and S. Thomson and Austin Bede Tomaney and Thor Vandehei and Alistair R. Walker and K. Ward and G M A Wyper},
  journal={The Astrophysical Journal},
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… Expand
Repeating microlensing events in the OGLE data
Microlensing events are usually selected among single-peaked non-repeating light curves in order to avoid confusion with variable stars. However, a microlensing event may exhibit a secondExpand
On the astrometric behaviour of binary microlensing events
Despite the suspected binarity for a significant fraction of Galactic lenses, the current photometric surveys detected binary microlensing events only for a small fraction of the total events. TheExpand
Gravitational Microlensing Events Due to Stellar-Mass Black Holes*
We present an analysis of the longest timescale microlensing events discovered by the MACHO Collaboration during a 7 year survey of the Galactic bulge. We find six events that exhibit very strongExpand
Gravitational microlensing events are powerful tools for the study of stellar populations. In particular, they can be used to discover and study a variety of binary systems. A large number of binaryExpand
Binary Events and Extragalactic Planets in Pixel Microlensing
Pixel microlensing, i.e., gravitational microlensing of unresolved stars, can be used to explore distant stellar systems and, as a bonus, may be able to detect extragalactic planets. In theseExpand
Galactic Bulge Microlensing Events from the MACHO Collaboration
The authors present a catalog of 450 relatively high signal-to-noise microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout the fieldsExpand
Investigating Binary Properties with Next-Generation Microlensing Surveys
We explore the potential usefulness of future gravitational microlensing surveys in studying binary properties such as the binary fraction and the distributions of binary separation and mass ratio byExpand
Microlensing constraints on the frequency of Jupiter-mass companions: Analysis of 5 years of PLANET photometry
We analyze 5 years of PLANET photometry of microlensing events toward the Galactic bulge to search for the short-duration deviations from single-lens light curves that are indicative of the presenceExpand
We analyze PLANET photometric observations of the caustic-crossing binary lens microlensing event, EROS BLG-2000-5, and find that modeling the observed light curve requires incorporation of theExpand
The MACHO Project: Microlensing Detection Efficiency
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 CloudExpand


A binary lensing event toward the LMC: Observations and dark matter implications
The MACHO collaboration has recently analyzed 2.1 years of photometric data for about 8.5 million stars in the Large Magellanic Cloud (LMC). This analysis has revealed 8 candidate microlensing eventsExpand
Identifying Microlensing by Binaries
The microlensing monitoring programs have studied large numbers of standard light curves that seem to be due to lensing by a dark point mass. Theory predicts that many microlensing events shouldExpand
Discovery and characterization of a caustic crossing microlensing event in the small Magellanic cloud
We present photometric observations and analysis of the second microlensing event detected toward the Small Magellanic Cloud (SMC), MACHO Alert 98-SMC-1. This event was detected early enough to allowExpand
Observations of the Binary Microlens Event MACHO 98-SMC-1 by the Microlensing Planet Search Collaboration
We present observations of the binary lensing event MACHO 98-SMC-1 conducted at the Mount Stromlo 1.9 m telescope by the Microlensing Planet Search (MPS) collaboration. The MPS data constrain theExpand
The MACHO Project Large Magellanic Cloud Microlensing Results from the First Two Years and the Nature of the Galactic Dark Halo
The MACHO Project is a search for dark matter in the form of massive compact halo objects (MACHOs). Photometric monitoring of millions of stars in the Large Magellanic Cloud (LMC), Small MagellanicExpand
Microlensing by multiple planets in high-magnification events
Microlensing is increasingly gaining recognition as a powerful method for the detection and characterization of extrasolar planetary systems. Naively, one might expect that the probability ofExpand
The Detectability of Planetary Companions of Compact Galactic Objects from Their Effects on Microlensed Light Curves of Distant Stars
We discuss a possible method for detection of dark companions of galactic objects of stellar mass. Such binary systems are likely to occur in the galactic disk and possibly also in the halo. The highExpand
The Use of High-Magnification Microlensing Events in Discovering Extrasolar Planets
Hundreds of gravitational microlensing events have now been detected toward the Galactic bulge, with many more to come. The detection of fine structure in these events has been theorized as anExpand
Abstract The statistical distribution of the masses of planets about stars between the Sun and the center of the Galaxy is constrained to within a factor of 3 by an intensive search for planetsExpand
A Caustic View of Halo Microlensing
The only microlensing events toward the Magellanic Clouds for which the location of the lens is strongly constrained are the two binary caustic crossing events. In at least one and possibly bothExpand