Related papers: Microlensing implications for halo dark matter
The recent binary microlensing event toward the Small Magellanic Cloud MACHO-98-SMC-1 was alerted by the MACHO collaboration and monitored by many microlensing experiments for its complete coverage of the second caustic crossing. The…
Microlensing events towards the Large Magellanic Cloud entail that a sizable fraction of dark matter is in the form of MACHOs (Massive Astrophysical Compact Halo Objects), presumably located in the halo of the Galaxy. Within the present…
We discuss the implications of the recent upward revision of the LMC microlensing rate by the MACHO Collaboration. We conclude: (i) A good case for the existence of baryonic dark matter in the halo has been made; (ii) The case for the…
The observed microlensing events towards the LMC do not have yet a coherent explanation. If they are due to Galactic Halo objects, the nature of these objects is puzzling --- half the halo in dark 0.5 Msol objects. On the other hand,…
Recently obtained kinematic data has shown that the Large Magellanic Cloud (LMC) possesses an old stellar halo. In order to further characterize the properties of this halo, parametric King models are fit to the surface density of RR Lyrae…
We detail how microlensing internal to M31 could be used to test whether a large fraction of the matter in spiral galaxy haloes is composed of dark objects with masses comparable to those of stars, and in the process show how the…
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…
If the microlensing events now being detected toward the Large Magellanic Cloud (LMC) are due to lenses in the Milky Way halo, then the events should typically have asymmetries of order 1% due to parallax from the reflex motion of the…
We review recent gravitational microlensing results from the EROS, MACHO, and OGLE collaborations, and present some details of the very latest MACHO results toward the Galactic Bulge. The MACHO collaboration has now discovered in excess of…
Dark matter could take the form of dark massive compact halo objects (dMACHOs); i.e., composite objects that are made up of dark-sector elementary particles, that could have a macroscopic mass from the Planck scale to above the solar mass…
If the dark halo of our galaxy is made of compact objects as massive as M = 10^6 solar masses, their detection by means of ordinary microlensing searches would take a very long time as the characteristic time scale of such a lensing event,…
The detection of microlensing has opened the way for the development of new methods in galactic astronomy. This series of papers investigates what microlensing can teach us about the structure and shape of the dark halo. In this paper we…
In a recent series of three papers, Belokurov, Evans, and Le Du, and Evans and Belokurov, reanalysed the MACHO collaboration data and gave alternative sets of microlensing events and an alternative optical depth to microlensing toward the…
The light curves of the two images of the double quasar Q0957+561 as obtained by Kundic et al. (1997) are almost identical, except for an overall time delay and scaling factor. This allows us to put limits on the amount of microlensing that…
The historical microlensing surveys MACHO, EROS, MOA and OGLE (hereafter summarized in the MEMO acronym) have searched for microlensing toward the LMC for a total duration of 27 years. We have studied the potential of joining all databases…
We present Hubble Space Telescope (HST) WFPC2 photometry of 13 microlensed source stars from the 5.7 year Large Magellanic Cloud (LMC) survey conducted by the MACHO Project. The microlensing source stars are identified by deriving accurate…
The discoveries of 17 microlensing event candidates have been reported over the last year by three teams conducting unprecedented mass photometric searches in the direction of the Galactic bulge and the Magellanic Clouds. These include 10…
Increasing evidences suggest that the Galactic halo is lumpy on kpc scales due to the accretion of at least a dozen small galaxies (LMC/SMC, Sgr, Fornax etc.). Faint stars in such lumpy structures can significant microlense a background…
We propose the existence of ultracompact minihalos as a new type of massive compact halo object (MACHO) and suggest an observational test to discover them. These new MACHOs are a powerful probe into the nature of dark matter and physics in…
MACHOs (Massive Astrophysical Compact Halo Objects) - as discovered by microlensing experiments towards the LMC - provide a natural explanation for the galactic halo dark matter. A realistic possibility is that MACHOs are brown dwarfs of…