A. Bouquet

Combined Analysis of the Binary Lens Caustic-crossing Event MACHO 98-SMC-1

We fit the data for the binary lens microlensing event MACHO 98-SMC-1 from five different microlensing collaborations and find two distinct solutions characterized by binary separation d and mass ratio q: (d,q) = (0.54,0.50) and (d,q) = (3.65,0.36), where d is in units of the Einstein radius. However, the relative proper motion of the lens is very similar in the two solutions, 1.30 km s-1 kpc-1 and 1.48 km s-1 kpc-1, thus confirming that the lens is in the Small Magellanic Cloud. The close binary can be either rotating or approximately static but the wide binary must be rotating at close to its maximum allowed rate to be consistent with all the data. We measure limb-darkening coefficients for five bands ranging from I to V. As expected, these progressively decrease with rising wavelength. This is the first measurement of limb darkening for a metal-poor A star.

Microlensing search towards M31

We present the first results of the analysis of data collected during the 1998-99 observational campaign at the 1.3 meter McGraw-Hill Telescope, towards the Andromeda galaxy (M 31), aimed to detect gravitational microlensing effects as a probe for the presence of dark matter in our Galaxy and in the M 31 halo. The analysis is performed using the pixel lensing technique, which consists of the study of flux variations of unresolved sources and has been proposed and implemented by the AGAPE collaboration. We carry out a shape analysis by demanding that the detected flux variations be achromatic and compatible with a Paczynski light curve. We apply the Durbin-Watson hypothesis test to the residuals. Furthermore, we consider the background of variables sources. Finally five candidate microlensing events emerge from our selection. Comparing with the predictions of a Monte Carlo simulation, assuming a standard spherical model for the M 31 and Galactic haloes, and typical values for the MACHO mass, we find that our events are only marginally consistent with the distribution of observable parameters predicted by the simulation.

EROS 2 proper motion survey: Constraints on the halo white dwarfs ?

We are conducting a 377 2 proper motion survey in the V and I bands in order to determine the cool white dwarf contribution to the Galactic dark matter. Using the 250 2 for which we possess three epochs, and applying selection criteria designed to isolate halo-type objects, we nd no candidates in a 5500 pc 3 eective volume for old, fast MV = 17 white dwarfs. We check the detection eciency by cross-matching our catalogue with Luytens NLTT catalogue. The halo white dwarf contribution cannot exceed 5% (95% C.L.) for objects with MV =1 7 and 1 V I 1:5. The same conclusion applies to a 14 Gyr halo composed of white dwarfs with hydrogen atmosphere, as modeled by Chabrier.We are conducting a 377-square-degree proper motion survey in the ~V and I bands in order to determine the cool white dwarf contribution to the Galactic dark matter. Using the 250 square degrees for which we possess three epochs, and applying selection criteria designed to isolate halo-type objects, we find no candidates in a 5500 pc^3 effective volume for old, fast M_V=17 white dwarfs. We check the detection efficiency by cross-matching our catalogue with Luytens NLTT catalogue. The halo white dwarf contribution cannot exceed 5% (95% C.L.) for objects with M_V=17 and 1<V-I<1.5. The same conclusion applies to a 14Gyr halo composed of white dwarfs with hydrogen atmosphere, as modeled by Chabrier (99).

Photometric constraints on microlens spectroscopy of EROS-BLG-2000-5

We apply EROS photometric data to interpret previously published Keck and VLT spectra of the binary-microlens caustic-crossing event EROS-BLG-2000-5. We show that the VLT data imply that the outer

Bulge microlensing optical depth from EROS 2 observations

{\sim} 4\%

A short-timescale candidate microlensing event in the point-agape pixel lensing survey of M31

of the limb of the K3-giant source is strongly in emission in H

The POINT-AGAPE survey: 4 high signal-to-noise microlensing candidates detected towards M 31

\alpha

Observation of microlensing toward the galactic spiral arms. EROS II 3 year survey

, in contradiction to available models of the photosphere. This conflict could be resolved if the integrated H

A Candidate M31/M32 Intergalactic Microlensing Event

\alpha

Variable stars towards the bulge of M 31: The AGAPE catalogue

emission from the chromosphere were equal to 8% of the integrated H