Related papers: Gravitational Microlensing and the Galactic Halo
The observations of microlensing events in the Large Magellanic Cloud suggest that a sizable fraction (\sim 50%) of the galactic halo is in the form of MACHOs (Massive Astrophysical Compact Halo Objects) with an average mass $\sim 0.27…
Results are presented from the MACHO collaboration gravitational microlensing search. The experiment and the nearly 50 microlensing events that have been detected are described. Limits on the baryonic content of the halo are given, as are…
In a previous study it was proposed that the Galactic dark matter being detected by gravitational microlensing experiments such as MACHO may reside in a population of dim halo globular clusters comprising mostly or entirely low-mass stars…
In the third part of the series presenting the Optical Gravitational Lensing Experiment (OGLE) microlensing studies of the dark matter halo compact objects (MACHOs) we describe results of the OGLE-III monitoring of the Large Magellanic…
Microlensing is the tool of choice for the search and the analysis of compact halo objects ("MACHOs"), a still viable class of dark matter candidates at the galactic scale. Different analyses point towards an agreement in excluding dark…
One of the biggest obstacles to our full understanding of the global dynamics in Milky Way and other spiral galaxies is uncertainty with respect to the form of baryonic dark matter in galactic haloes. Two basic forms discussed recently are…
The nature of the dark matter in the halo of our Galaxy is still largely unknown. The microlensing events found so far towards the Large Magellanic Cloud suggest that at most about 20% of the halo dark matter is in the form of MACHOs…
Massive Compact objects in the halo, known as MACHOs, have been postulated as the origin of a substantial fraction of `dark matter' known to exist in the haloes of galaxies$^{1,2}$. Paczy\'nski$^3$ has suggested that it might possible to…
After a decade of gravitational microlensing experiments, a dozen of microlensing candidates in the direction of the stars of the Large Magellanic Cloud (LMC) have been detected by the EROS and MACHO groups. Recently it was shown that the…
The failure to find evidence for elementary particles that could serve as the constituents of dark matter brings to mind suggestions that dark matter might consist of massive compact objects (MACHOs). In particular, it has recently been…
The measurements of the possible gravitational microlensing events are analysed with a simple yet accurate disc--halo model of the Milky Way Galaxy. This comprises a luminous exponential disc embedded in a flattened dark matter halo with…
(Abridged version): The optical depth is widely used in Galactic microlensing studies as a means to determine the density of MACHOs, since in theory it depends only upon their spatial distribution and is therefore less model-dependent than…
Dark matter is an important ingredient of galaxies, as was recognised early on by Ken Freeman himself! Evidence for dark matter halos is still indirect, based on analysing motions of tracers such as gas and stars. In a sense the visible…
We analyze the first-year MACHO collaboration observations of microlensing towards the Galactic center using a new direct likelihood technique that is sensitive to the distribution of the events on the sky. We consider the full set of 41…
We examine the most recent observational constraints arising from i) small-scale and large-scale Galactic dynamical properties, ii) star counts at faint magnitude and iii) microlensing experiments. From these constraints, we determine the…
Since the first discovery of microlensing events nearly two decades ago, gravitational microlensing has accumulated tens of TBytes of data and developed into a powerful astrophysical technique with diverse applications. The review starts…
Microlensing surveys search for the transient brightening of a background star that is the signature of gravitational lensing by a foreground compact object. This technique is an elegant way to search for astrophysical candidates that might…
The recent observations of microlensing events in the LMC by the MACHO and EROS collaborations suggest that an important fraction of the galactic halo is in the form of Massive Halo Objects (MHO) of about 0.1 M_{\odot}. Here, we argue that…
Five years of EROS data towards the Small Magellanic Cloud have been searched for gravitational microlensing events, using a new, more accurate method to assess the impact of stellar blending on the efficiency. Four long-duration candidates…
It has been proposed that the MACHOs in our galaxy could be clumped in globular cluster--like associations or RAMBOs (robust associations of massive baryonic objects) (Moore \& Silk 1995). Here we investigate the effect such clustering has…