Related papers: A new direction for dark matter research: intermed…
The dark matter in Galactic halos, or some fraction of it, may be in the form of dark clusters which consist of small mass objects. Carr & Lacey (1987) have derived the permissible properties of such systems, and proposed the existence of…
A straightforward interpretation of the MACHO microlensing results in the direction of the Magellanic Clouds suggests that an important fraction of the baryonic dark matter component of our Galaxy is in the form of old white dwarfs. If…
[Abridged] We estimate the contribution of Massive Compact Halo Objects (Machos) and their stellar progenitors to the mass density of the Universe. If the Machos that have been detected reside in the Halo of our Galaxy, then a simple…
The idea that dark matter in the form of small compact bodies (most plausibly planetary mass primordial black holes) betrays its presence by the microlensing of quasars, has been stimulated by statistical studies of quasar light curves and…
Recent results from gravitational microlensing experiments, such as MACHO, indicate that a substantial fraction of the Galactic dark matter (DM) is in compact form, with a typical mass in the range ~0.05 - 1 Mo. This mass range favours the…
We consider the contribution of neutron stars and black holes to the dynamical mass of galactic halos. In particular, we show that if these compact objects were produced by an early generation of stars with initial metallicity less than…
One of the most important problems in astrophysics concerns the nature of the dark matter in galactic halos, whose presence is implied mainly by the observed flat rotation curves in spiral galaxies. Due to the Pauli exclusion principle it…
We derive a complementary cosmological upper bound on the fraction of dark matter residing inside massive compact halo objects (MACHOs) using the cosmic dawn and dark ages global 21-cm signal $(T_{21})$. MACHOs of masses $M\gtrsim…
The MACHO Project is searching for galactic dark matter in the form of massive compact halo objects (Machos). Millions of stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge are photometrically…
The discovery of Massive Astrophysical Compact Halo Objects (MACHOs) in microlensing experiments makes it compelling to understand their physical nature, as well as their formation mechanism. Within the present uncertainties, brown dwarfs…
We consider the possibility that the dark matter in the halos of galaxies may be in the form of clusters of \macho s within which are embedded cold, dense gas clouds. Microlensing experiments have found evidence that the Galactic halo…
Massive Compact objects in the halo, known as MACHOs, have been postulated as the origin of a substantial fraction of `dark matter' known to exist in the haloes of galaxies$^{1,2}$. Paczy\'nski$^3$ has suggested that it might possible to…
In the framework of the search of dark matter in galactic halos in form of massive compact halo object (MACHOs), we discuss the status of microlensing observations towards the Magellanic Clouds and the Andromeda galaxy, M31. The detection…
By means of extensive galactic modeling we study the implications of the more than eighty microlensing events that have now been observed for the composition of the dark halo of the Galaxy, as well as for other properties of the Galaxy. We…
We explore a novel search strategy for dark matter in the form of massive compact halo objects (MACHOs) such as primordial black holes or dense mini-halos in the mass range from $10^{-4}$ to 0.1 solar masses. These objects can…
I review proposals for explaining the current gravitational microlensing results from the EROS and MACHO surveys towards the Magellanic Clouds. Solutions involving massive compact halo objects (MACHOs), both baryonic and non-baryonic, as…
Recently the French EROS collaboration and the American-Australian MACHO collaboration have reported the observation of altogether three possible microlensing events by monitoring over several years the brightness of millions of stars in…
By means of extensive galactic modeling we study the implications of the more than 100 microlensing events that have now been observed for the composition of the dark halo of the Galaxy. Based on the currently published data, including the…
Recent observations of microlensing events in the Large Magellanic Cloud by the MACHO and EROS collaborations suggest that an important fraction of the galactic halo is in the form of Massive Halo Objects (MHO) with mass $\sim 0.1…
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…