Not enough stellar mass Machos in the Galactic halo

Abstract

We present an update of results from the search for microlensing towards the Large Magellanic Cloud (LMC) by EROS (Experience de Recherche d'Objets Sombres). We have now monitored 25 million stars over three years. Because of the small number of observed microlensing candidates (four), our results are best presented as upper limits on the amount of dark compact objects in the halo of our Galaxy. We discuss critically the candidates and the possible location of the lenses, halo or LMC . We compare our results to those of the MACHO group. Finally, we combine these new results with those from our search towards the Small Magellanic Cloud as well as earlier ones from the EROS1 phase of our survey. The combined data is sensitive to compact objects in the broad mass range $10^{-7}-10$ solar masses. The derived upper limit on the abundance of stellar mass MACHOs rules out such objects as the dominant component of the Galactic halo if their mass is smaller than 2 solar masses.

arXiv comment7 pages, 4 figures, presented at the XIX International Conference on Neutrino Physics and Astrophysics, Sudbury, Canada, June 2000

References in corpus (9)

• Possible Gravitational Microlensing of a Star in the Large Magellanic Cloud
• The MACHO Project LMC Microlensing Results from the First Two Years and the Nature of the Galactic Dark Halo
• EROS and MACHO Combined Limits on Planetary Mass Dark Matter in the Galactic Halo
• Stars within the Large Magellanic Cloud as Potential Lenses for Observed Microlensing Events
• Discovery of high proper motion ancient white dwarfs: nearby massive compact halo objects?
• Faint, moving objects in the Hubble Deep Field: components of the dark halo?
• First detection of a gravitational microlensing candidate towards the Small Magellanic Cloud
• The MACHO Project: Limits on Planetary Mass Dark Matter in the Galactic Halo from Gravitational Microlensing
• Gravitational Microlensing by the MACHOs of the LMC

Cited by in corpus (10)

• Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds
• A White Paper on keV Sterile Neutrino Dark Matter
• Illuminating Hot Jupiters in caustic crossing
• Microlensing towards the Large Magellanic Cloud
• Compact object detection in self-lensing binary systems with a main-sequence star
• Transient Weak-Lensing by Cosmological Dark Matter Microhaloes
• Are there MACHOs in the Milky Way halo?
• Statistical Interpretation of LMC Microlensing Candidates
• The Galactic Halo from Microlensing
• Simulation of a strategy for the pixel lensing of M87 using the Hubble Space Telescope