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The EROS and MACHO collaborations have each published upper limits on the amount of planetary mass dark matter in the Galactic Halo obtained from gravitational microlensing searches. In this paper the two limits are combined to give a much stronger constraint on the abundance of low mass MACHOs. Specifically, objects with masses 10 −7 M ⊙ < ∼ m < ∼ 10 −3 M ⊙ make up less than 25% of the halo dark matter for most models considered, and less than 10% of a standard spherical halo is made of MACHOs in the 3.5 × 10 −7 M ⊙ < m < 4.5 × 10 −5 M ⊙ mass range.

We report the discovery of 30 type a,b RR Lyrae (RRab) which are likely members of the Sagittarius (Sgr) dwarf galaxy. Accurate positions, periods, amplitudes and magnitudes are presented. Their distances are determined with respect to RRab in the Galactic bulge found also in the MACHO 1993 data. For R ⊙ = 8 kpc, the mean distance to these stars is D = 22 ± 1 kpc, smaller

We present photometric observations and analysis of the second microlensing event detected towards the Small Magellanic Cloud (SMC), MACHO Alert 98-SMC-1. This event was detected early enough to allow intensive observation of the lightcurve. These observations revealed 98-SMC-1 to be the first caustic crossing, binary microlensing event towards the Magellanic Clouds to be discovered in progress.Frequent coverage of the evolving lightcurve allowed an accurate prediction for the date of the source crossing out of the lens caustic structure. The caustic crossing temporal width, along with the angular size of the source star, measures the proper motion of the lens with respect to the source, and thus allows an estimate of the location of the lens. Lenses located in the Galactic halo would have a velocity projected to the SMC of v ∼ 1500 km s −1 , while an SMC lens would typically have v ∼ 60 km s −1 . The event lightcurve allows us to obtain a unique fit to the parameters of the binary lens, and to estimate the proper motion of the lensing system.We have performed a joint fit to the MACHO/GMAN data presented here, including recent EROS data of this event (Afonso et al. 1998). These joint data are sufficient to constrain the time t * for the lens to move an angle equal to the source angular radius; t * = 0.116 ± 0.010 days. We estimate a radius for the lensed source of R * = 1.4 ± 0.1R ⊙ from its unblended color and magnitude. This yields a projected velocity of v = 84 ± 9 km s −1 . Only 0.15 % of halo lenses would be expected to have a v value at least as small as this, while 31% of SMC lenses would be expected to have v as large as this. This implies that the lensing system is more likely to reside in the SMC than in the Galactic halo. Similar observations of future Magellanic Cloud microlensing events will help to determine the contribution of Machos to the Galaxy's dark halo.