Microlensing towards LMC: a study of the LMC halo contribution

Abstract

We carry on a new analysis of the sample of MACHO microlensing candidates towards the LMC. Our main purpose is to determine the lens population to which the events may belong. We give particular emphasis to the possibility of characterizing the Milky Way dark matter halo population with respect to the LMC one. Indeed, we show that only a fraction of the events have characteristics that match those expected for lenses belonging to the MACHO population of the Milky Way halo. This suggests that this component cannot explain all the candidates. Accordingly, we challenge the view that the dark matter halo fraction of both the Milky Way and the LMC halos are equal, and indeed we show that, for a MACHO mass in the range 0.1-0.3 M${}_{\odot }$, the LMC halo fraction can be significantly larger than the Milky Way one. In this perspective, our main conclusion is that up to about half of the observed events could be attributed to the LMC MACHO dark matter halo.

Accepted for publication in Astronomy & Astrophysics

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• Microlensing as a probe of the Galactic structure; 20 years of microlensing optical depth studies
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• Microlensing towards the LMC: self lensing for OGLE-II and OGLE-III
• Pixel lensing: Microlensing towards M31
• The Structure of the Large Magellanic Halo Stellar Halo Derived Using OGLE-III RR Lyr stars
• LMC self lensing for OGLE-II microlensing observations
• Candidate microlensing events from M31 observations with the Loiano telescope
• Probing MACHOs by observation of M31 pixel lensing with the 1.5m Loiano telescope
• The contribution of red dwarfs and white dwarfs to the halo dark matter
• M31 Pixel Lensing PLAN Campaign: MACHO Lensing and Self Lensing Signals
• Constraints on Galaxy Structure and Evolution from the Light of Nearby Systems
• Microlensing towards the LMC revisited by adopting a non-Gaussian velocity distribution for the sources
• Microlensing towards the Magellanic Clouds and M31: is the quest for MACHOs still open?
• Gravitational microlensing constraints on primordial black holes by Euclid
• Limits on compact halo objects as dark matter from gravitational microlensing