Related papers: MACHOs and molecular clouds in galactic halos
The primary goal of this paper is to provide the evidence that can either prove or falsify the hypothesis that dark matter in the Galactic halo can clump into stellar-mass compact objects. If such objects existed, they would act as lenses…
After a decade of gravitational microlensing experiments, 13 to 17 events by MACHO (depending on quality) and two events by EROS have been detected. All of those have been observed in the direction of Large Magellanic Cloud. We use Evans…
It has been revealed using microlensing that a considerable part, possibly more than half, of the dark matter in the halo of our Galaxy consists of objects with a mass spectrum ranging from 0.05 to 0.8 of the solar mass. What is the nature…
(Abridged Abstract) A favored interpretation of recent microlensing measurements towards the Large Magellanic Cloud implies that a large fraction (i.e. 10--50%) of the mass of the galactic halo is composed of white dwarfs. We compare model…
Recent determination of the outer rotation curve of the Galaxy suggests that the total Galactic mass is likely to concentrate into a region of radius $\sim2R_0$. If this finding is correct, the previously estimated optical depth of…
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…
We examine Milky Way-Magellanic Cloud systems selected from the Millennium-II Simulation in order to place the orbits of the Magellanic Clouds in a cosmological context. Our analysis shows that satellites massive enough to be LMC analogs…
EROS (Exp\'erience de Recherche d'Objets Sombres) has been monitoring the luminosity of 4 million stars in the Large Magellanic Cloud in order to search for gravitational microlensing by unseen objects in the galactic halo. We present here…
We use numerical simulations to examine the substructure within galactic and cluster mass halos that form within a hierarchical universe. Clusters are easily reproduced with a steep mass spectrum of thousands of substructure clumps that…
I present a new analysis of the MACHO Project 5.7 year Large Magellanic Cloud (LMC) microlensing data set that incorporates the effects of contamination of the microlensing event sample by variable stars. Photometric monitoring of MACHO LMC…
The aim of this study is to characterize the distribution and basic properties of the natal gas associated with high-mass young stellar objects (YSOs) in isolated environments in the Large Magellanic Cloud (LMC). High-mass stars usually…
We investigated the dependence of the optical depth $\tau$ of the microlensing events on model parameters of the Galactic halo. We only consider Galactic mass models in which the rotation curve inside the Sun is compatible with the…
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…
(Short version) The nature and the location of the lenses discovered in the microlensing surveys done so far towards the LMC remain unclear. This contribution is comprised of two distinct parts. In the first part, motivated by these…
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…
Disk-halo models of the Galaxy and LMC are constructed and used to analyse the microlensing data-set. Deflectors in the LMC bar, disk and halo provide an optical depth to microlensing of $\sim 2 \times 10^{-7}$. Deflectors in the Galactic…
Most of the mass density in the Universe---and in the halo of our own galaxy---exists in the form of dark matter. Overall, the contribution of luminous matter (in stars) to the mass density of the Universe is less than 1\%; primordial…
We investigate the implications of a bulk rotational component of the halo velocity distribution for MACHO mass estimates. We find that for a rotating halo to yield a MACHO mass estimate significantly below that of the standard spherical…
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…
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…