EXPERIMENTAL LIMITS ON THE DARK MATTER HALO OF THE GALAXY FROM GRAVITATIONAL MICROLENSING.

Abstract

We have monitored 8.6 million stars in the Large Magellanic Cloud for 1.1 years and have found 3 events consistent with gravitational microlensing. We place strong constraints on the Galactic halo content in the form of compact lensing objects in the mass range $10^{-4} \msun$ to $10^{-1} \msun$. Three events is fewer than expected for a standard spherical halo of objects in this mass range, but appears to exceed the number expected from known Galactic populations. Fitting a naive spherical halo model to our data yields a MACHO fraction $f=0.20_{-0.14}^{+0.33}$, which implies a total MACHO mass (inside 50 kpc) of $8.0^{+14}_{-6}\ten{10} \msun$, and a microlensing optical depth $9^{+15}_{-7} \ten{-8}$ ($\sim 68$\% CL).

arXiv comment8 pages, uuencoded compressed PostScript, 4 figures included (400kB). Submitted to Phys Rev Lett.

References in corpus (4)

• Possible Gravitational Microlensing of a Star in the Large Magellanic Cloud
• Big-Bang Nucleosynthesis and the Baryon Density of the Universe
• Stars within the Large Magellanic Cloud as Potential Lenses for Observed Microlensing Events
• Gravitational Microlensing by the MACHOs of the LMC

Cited by in corpus (73)

• Supersymmetric Dark Matter
• The MACHO Project LMC Microlensing Results from the First Two Years and the Nature of the Galactic Dark Halo
• Big Bang nucleosynthesis and physics beyond the Standard Model
• Gravitational Microlensing in the Local Group
• Chaotic new inflation and formation of primordial black holes
• First Observation of Parallax in a Gravitational Microlensing Event
• The MACHO Project: 45 Candidate Microlensing Events from the First Year Galactic Bulge Data
• Cosmological constraints on primordial black holes produced in the near-critical gravitational collapse
• Non-Cold Dark Matter from Primordial Black Hole Evaporation
• The Local Halo Density
• Confirmation of high deuterium abundance in QSO absorbers
• Contribution of brown dwarfs and white dwarfs to recent microlensing observations and to the halo mass budget
• Resonance sweeping by a decelerating Galactic bar
• Hubble Deep Field Constraint on Baryonic Dark Matter
• Cold Dark Matter Models
• Primordial Black Holes and Primordial Nucleosynthesis I: Effects of Hadron Injection from Low Mass Holes
• The role of ionization electrons in direct dark matter detection
• Non-Newtonian behavior in weak field general relativity for extended rotating sources
• Direct dark matter search by observing electrons produced in neutralino-nucleus collisions
• Analysis of a Hubble Space Telescope Search for Red Dwarfs: Limits on Baryonic Matter in the Galactic Halo
• Microlensing Events from Measurements of the Deflection Angle
• Microlensing
• Microlensing and Halo Cold Dark Matter
• Theoretical Directional and Modulated Rates for Direct SUSY Dark Matter Detection
• Cold Dark Matter in SUSY Theories. The Role of Nuclear Form Factors and the Folding with the LSP Velocity
• Gravitational Waves from Compact Dark Objects in Neutron Stars
• Gravitational Microlensing and the Galactic Halo
• Searching for Supersymmetric Dark Matter - The Directional Rate and the Modulation Effect Due to Caustic Rings
• The modulation effect for supersymmetric dark matter detection with asymmetric velocity dispersion
• A 421 d Activity Cycle in the BeX Recurrent Transient A0538-66 from MACHO monitoring
• X-Ray Off States and Optical Variability in CAL 83
• Barotropic fluid compatible parametrizations of dark energy
• Gravitational Microlensing - A Report on the MACHO Project
• Density Fluctuations and Primordial Black Hole Formation in Natural Double Inflation in Supergravity
• Search for an annual modulation of dark-matter signals with a germanium spectrometer at the Sierra Grande Laboratory
• Gravitational waves from compact dark matter objects in the solar system
• Theoretical direct WIMP detection rates for transitions to excited states
• Direct Dark Matter Detection - A spin 3/2 WIMP candidate
• Axionic Boson Stars in Magnetized Conducting Media
• Direct dark matter searches - Test of the Big Bounce Cosmology
• Primordial black holes under the double inflationary power spectrum
• Direct Detection Rates of Dark Matter Coupled to Dark Energy
• Gravimeter search for compact dark matter objects moving in the Earth
• Modulation effect in the differential rate for Supersymmetric Dark Matter detection
• Direct Wimp Detection in Directional Experiments
• Direct Dark Matter Detection with Velocity Distribution in the Eddington approach
• XMM Spectroscopy of the Transient Supersoft Source RX J0513.9-6951: probing the dynamic white dwarf photosphere
• Dark sector unifications: dark matter-phantom energy, dark matter -- constant $w$ dark energy, dark matter-dark energy-dark matter
• The Deuteron Confronts Big Bang Nucleosynthesis
• MACHO Photometry of Two LMC Be X-ray Transients, EXO 0531-66 and H 0544-665
• Searching for Dark Matter- Theoretical Rates and Exclusion Plots due to the Spin
• Cosmological Applications of Gravitational Lensing
• X Rays from Old Neutron Stars Heated by Axion Stars
• Self-Microlensing in Compact Binary Systems
• Searching for periodicities in the MACHO light curve of LMC X-2
• Halo Density Profiles Consistent with Asymmetric M-B Velocity Distributions-Implications on Direct Dark Matter Searches
• Transient dark energy, cosmological constant boundary crossing and dark energy $w(z)$ data fits
• Very Cold Gas and Dark Matter
• Predicted modulated differential rates for direct WIMP searches at low energy transfers
• Distortions of Robertson-Walker metric in perturbative cosmology and interpretation as dark matter and cosmological constant
• Solar neutrinos as background in dark matter searches involving electron detection
• New Velocity Distribution in the Context of the Eddington Theory
• Dark matter fluid constraints from galaxy rotation curves
• Probing the equation of state of neutron stars with captured primordial black holes
• Direct dark matter detection: The diurnal variation in directional experiments
• Predicted rates for direct WIMP searches
• Astroparticle physics - A Personal Outlook
• Gravitational Microlensing, The Distance Scale, And The Ages
• Gravitational Microlensing Rates in Milky Way Globular Clusters
• Microlensing path parametrization for Earth-like Exoplanet detection around solar mass stars
• The MACHO Project 2nd Year LMC Microlensing Results and Dark Matter Implications
• The Nature of Dark Matter
• The role of thermal instabilities on the theoretical mass function of MACHOs