Galactic Bulge Microlensing Events from the MACHO Collaboration

Abstract

We present a catalog of 450 high signal-to-noise microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout our fields and, as expected, they show clear concentration toward the Galactic center. No optical depth is given for this sample since no blending efficiency calculation has been performed, and we find evidence for substantial blending. In a companion paper we give optical depths for the sub-sample of events on clump giant source stars, where blending is not a significant effect. Several events with sources that may belong to the Sagittarius dwarf galaxy are identified. For these events even relatively low dispersion spectra could suffice to classify these events as either consistent with Sagittarius membership or as non-Sagittarius sources. Several unusual events, such as microlensing of periodic variable source stars, binary lens events, and an event showing extended source effects are identified. We also identify a number of contaminating background events as cataclysmic variable stars.

34 pages, 9 figures + 3 example lightcurves, all 564 lightcurves will be available at http://wwwmacho.mcmaster.ca, submitted to ApJ, see companion paper by Popowski et al

References in corpus (13)

• Theoretical isochrones in several photometric systems I. Johnson-Cousins-Glass, HST/WFPC2, HST/NICMOS, Washington, and ESO Imaging Survey filter sets
• Microlensing optical depth towards the Galactic bulge from MOA observations during 2000 with Difference Image Analysis
• Stellar Contribution to the Galactic Bulge Microlensing Optical Depth
• Gravitational Microlensing Events Due to Stellar Mass Black Holes
• Microlensing Constraints on the Frequency of Jupiter-Mass Companions: Analysis of Five Years of PLANET Photometry
• Microlensing Optical Depth towards the Galactic Bulge Using Clump Giants from the MACHO Survey
• Bulge Microlensing Optical Depth from EROS 2 observations
• First detection of the RGB-bump in the Sagittarius dSph
• The Large-Scale Extinction Map of the Galactic Bulge from the MACHO Project Photometry
• Preliminary Abundance Analysis of Galactic Bulge Main Sequence, Subgiant, and Giant Branch Stars Observed During Microlensing with Keck/HIRES
• An inner ring and the micro lensing toward the Bulge
• The Sagittarius dwarf galaxy as a microlensing target
• Studying the Galactic Bulge Through Spectroscopy of Microlensed Sources: II. Observations

Cited by in corpus (23)

• Experimental Limits on Primordial Black Hole Dark Matter from the First Two Years of Kepler Data
• Microlensing Optical Depth towards the Galactic Bulge Using Clump Giants from the MACHO Survey
• Microlensing optical depth toward the Galactic Bulge using bright sources from OGLE-II
• QSO Selection Algorithm Using Time Variability and Machine Learning: Selection of 1,620 QSO Candidates from MACHO LMC Database
• Constraints on compact dark matter from gravitational wave microlensing
• Modeling microlensing events with MulensModel
• Proper Motion Dispersions of Red Clump Giants in the Galactic Bulge: Observations and Model Comparisons
• Supervised detection of anomalous light-curves in massive astronomical catalogs
• The EROS2 search for microlensing events towards the spiral arms: the complete seven season results
• An improved quasar detection method in EROS-2 and MACHO LMC datasets
• The first direct detection of a gravitational micro-lens toward the Galactic bulge
• Discovery of a Very Bright, Nearby Gravitational Microlensing Event
• Anisotropic Dark Matter Stars
• Gravitational Lensing and Structural Stability of Dark Matter Caustic Rings
• Microlensing of Circumstellar Disks
• Online classification for time-domain astronomy
• Microlensing modulation by quadrupole variation
• Galactic globular clusters contribution to microlensing events?
• Using microlensed quasars to probe the structure of the Milky Way
• Microlensing optical depth as a function of source apparent magnitude
• Matching microlensing events with X-ray sources
• Probing Cold Dark Matter Cusps by Gravitational Lensing
• Microlensing pulsars