All Figures

$\begin{figure} \par\includegraphics[width=7.4cm,clip]{6017fg01.eps} \end{figure}$ Figure 1: Map of the EROS-2 LMC and SMC fields in equatorial coordinates. A total of 88 LMC and 10 SMC fields were monitored. The first number in each field is the field number and the second is the number of bright stars (as defined in Sect. 3) in the field in units of 10⁴. The two shaded regions (the larger one centered on the LMC bar) are the $13.4~\rm deg^2$ used by the MACHO collaboration to measure the optical depth (Alcock et al. 2000b).
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In the text

$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg02.eps} \end{figure}$ Figure 2: The photometric precision as a function of $R_{\rm eros}$ for the dense field lm009 ( top) and the sparse field lm048 ( bottom). Each point represents the rms dispersion of the measurements for a single star after elimination of outliers. The vertical line shows the position of the bright-star magnitude cut (5) for the field, $R_{\rm eros}=18.23$ for lm009 CCDs 0-3 and $R_{\rm eros}=19.7$ for lm048 CCDs 0-3.
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In the text

$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg03.eps} \end{figure}$ Figure 3: The flux precision, $\Delta \phi /\phi$ , for the Bright-Star Sample (2% of the sample are in the histograms). Each entry is the mean flux uncertainty for a star on its light curve. The top ( bottom) histograms are for the $R_{\rm eros}$ ( $B_{\rm eros}$ ) bands.
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In the text

$\begin{figure} \par\includegraphics[width=15.8cm,clip]{6017fg04.eps}\end{figure}$ Figure 4: The effects of blending on artificial stars added to the dense field lm009 ( left) and the sparse field lm048 ( right). The top two panels show the distribution of $\alpha _1$ using artificial stars that do not fall under a brighter pre-existing object. Stars further than 2 arcsec from the nearest pre-existing object are concentrated in the peak at $\alpha _1\sim 1$ while stars nearer to pre-existing objects form the tail at $\alpha _1 <1$ . The middle two panels show, for objects within 2 arcsec of pre-existing objects, the correlation between $\alpha _1$ and the difference in magnitude between the artificial star and the pre-existing object. Artificial objects with $\alpha _1$ significantly below unity are associated with pre-existing objects of similar magnitude. The line shows the expected relation for two superimposed objects: $\alpha _1=1./(1.+10^{0.4\Delta R})$ . The bottom two panels show the distribution of $(\alpha _1,\alpha _2)$ with $\alpha _2$ calculated from (12) and the magnitude of the pre-existing object. The line shows the expected relation for two superimposed objects: $\alpha _1 + \alpha _2 =1$ .
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In the text

$\begin{figure} \par\includegraphics[width=7cm,clip]{6017fg05.eps}\end{figure}$ Figure 5: The distribution of u₁ (solid line) and (u₁+u₂) dashed line for the sparse EROS field lm048 ( top panel) the dense EROS field lm009 ( middle panel) and the very dense HST field in lm009, ccd3 ( bottom panel) as described in the text. The distributions of u₁ are all characterized by a peak near $u_1\sim 1$ and a tail at u₁<1. With increasing star density, the mean of u₁+u₂ increases because of the increasing importance of secondary stars.
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In the text

$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg06.eps} \end{figure}$ Figure 6: The u₀ (mean of those for $R_{\rm eros}$ and $B_{\rm eros}$ ) distribution for LMC and SMC light curves surviving cuts C1-C7, C1-C8, and C1-C9. The positions of the 14 light curves surviving cuts C1-C10 are shown with the 4 supernovae as dashed lines.
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In the text

$\begin{figure} \par\includegraphics[width=15cm,clip]{6017fg07.eps} \end{figure}$ Figure 7: The light curves of EROS-2 microlensing candidate EROS2-SMC-1 (star sm005-4m-5761). Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.
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In the text

$\begin{figure} \par\includegraphics[width=15cm,clip]{6017fg08.eps} \end{figure}$ Figure 8: The light curves of EROS-2 star lm057-0n-29305 ( $\rm RA=79.9488~\rm deg$ , Dec = $-70.7741~\rm deg$ ). Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.
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In the text

$\begin{figure} \par\includegraphics[width=15cm,clip]{6017fg09.eps} \end{figure}$ Figure 9: The EROS-2 light curve of EROS-1 microlensing candidate EROS1-LMC-1. The curve shows a second variation, 6.3 years after the variation observed in EROS-1. Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.
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In the text

$\begin{figure} \par\includegraphics[width=15cm,clip]{6017fg10.eps} \end{figure}$ Figure 10: The EROS-2 light curve of MACHO microlensing candidate MACHO-LMC-23. The curve shows a second variation, 6.8 years after the variation seen by MACHO. Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.
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In the text

$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg11.eps} \end{figure}$ Figure 11: The detection efficiency for unblended ( $\alpha =1$ ) microlensing light curves (10) as a function of $t_{\rm E}$ for LMC (bold line) and SMC (light line) fields. The efficiency applies to a $2500~\rm d$ total observing period. The efficiency used for calculation of the optical depth is the efficiency shown here, multiplied by 0.9 to take into account lensing by binary lenses.
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In the text

$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg12.eps} \end{figure}$ Figure 12: The ratio between the summed efficiency, $\epsilon _1(\alpha _1)+\epsilon _2(\alpha _2)$ and the unblended efficiency $\epsilon (\alpha =1)$ for pairs $(\alpha _1,\alpha _2)$ taken from the artificial star analysis of Sect. 3. The ratio is a function of $t_{\rm E}$ . The four curves correspond to the four studied fields, lm009, 019, 034 and 048.
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In the text

$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg13.eps}\end{figure}$ Figure 13: The detection efficiency for simple microlensing light curves (10) as a function of u₀ ( top) and of $R_{\rm eros}$ ( bottom) for LMC and SMC events in the range $10~\rm d<t_{\rm E}<200~\rm d$ .
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In the text

$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg14.eps}\end{figure}$ Figure 14: The $t_{\rm E}$ distribution ${\rm d}\Gamma /{\rm d}t_{\rm E}$ expected for $1M_\odot$ lenses in a spherically symmetric isothermal halo with core radius $5~{\rm kpc}$ , i.e. the S model used by the MACHO collaboration (Alcock et al. 2000b).
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In the text

$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg15.eps} \end{figure}$ Figure 15: The top panel shows the numbers of expected events as a function of macho mass M for the S model of Alcock et al. (2000b). The expectations for EROS-2-LMC, SMC (this work) are shown along with those of EROS-1 (Renault et al. 1997) with contributions from the photographic plate program (Ansari et al. 1996a) and CCD program (Renault et al. 1998). The number of events for EROS-2-SMC supposes $\tau _{\rm smc}=1.4\tau _{\rm lmc}$ . In the lower panel the solid line shows the EROS 95% CL upper limit on $f=\tau _{\rm lmc}/4.7\times 10^{-7}$ based on no observed events in the EROS-2 LMC data and the EROS-1 data. The dashed line shows the EROS upper limit on $\tau _{\rm lmc}$ based on one observed SMC event in all EROS-2 and EROS-1 data assuming $\tau _{\rm smc-halo}=1.4\tau _{\rm lmc}$ . The MACHO 95% CL. curve is taken from Fig. 12 (A, no lmc halo) of Alcock et al. (2000b).
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In the text

$\begin{figure} \par\includegraphics[width=16cm,clip]{6017ap01.eps} \end{figure}$ Figure A.1: The light curves of EROS-2 star lm055-7m-23303. Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.

In the text

$\begin{figure} \par\includegraphics[width=16cm,clip]{6017ap02.eps} \end{figure}$ Figure A.2: The light curves of EROS-2 star lm042-1l-2622. Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.

In the text

$\begin{figure} \par\includegraphics[width=16cm,clip]{6017ap03.eps} \end{figure}$ Figure A.3: The light curves of EROS-2 star lm045-5n-26323. Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event. Note the visible asymmetry in the B light curve, possibly indicative of a supernova.

In the text

$\begin{figure} \par\includegraphics[width=16cm,clip]{6017ap04.eps} \end{figure}$ Figure A.4: The light curves of EROS-2 star lm061-4m-15782. Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.

In the text

$\begin{figure} \par\includegraphics[width=16cm,clip]{6017ap05.eps} \end{figure}$ Figure A.5: The light curves of EROS-2 star lm085-6l-14234. Also shown is the color-magnitude diagram of the star's CCD-quadrant and the position of the source's baseline.

In the text

$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg03.eps} \end{figure}$	Figure 3: The flux precision, $\Delta \phi /\phi$ , for the Bright-Star Sample (2% of the sample are in the histograms). Each entry is the mean flux uncertainty for a star on its light curve. The top ( bottom) histograms are for the $R_{\rm eros}$ ( $B_{\rm eros}$ ) bands.
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$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg06.eps} \end{figure}$	Figure 6: The u₀ (mean of those for $R_{\rm eros}$ and $B_{\rm eros}$ ) distribution for LMC and SMC light curves surviving cuts C1-C7, C1-C8, and C1-C9. The positions of the 14 light curves surviving cuts C1-C10 are shown with the 4 supernovae as dashed lines.
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$\begin{figure} \par\includegraphics[width=15cm,clip]{6017fg07.eps} \end{figure}$	Figure 7: The light curves of EROS-2 microlensing candidate EROS2-SMC-1 (star sm005-4m-5761). Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.
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$\begin{figure} \par\includegraphics[width=15cm,clip]{6017fg08.eps} \end{figure}$	Figure 8: The light curves of EROS-2 star lm057-0n-29305 ( $\rm RA=79.9488~\rm deg$ , Dec = $-70.7741~\rm deg$ ). Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.
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$\begin{figure} \par\includegraphics[width=15cm,clip]{6017fg09.eps} \end{figure}$	Figure 9: The EROS-2 light curve of EROS-1 microlensing candidate EROS1-LMC-1. The curve shows a second variation, 6.3 years after the variation observed in EROS-1. Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.
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$\begin{figure} \par\includegraphics[width=15cm,clip]{6017fg10.eps} \end{figure}$	Figure 10: The EROS-2 light curve of MACHO microlensing candidate MACHO-LMC-23. The curve shows a second variation, 6.8 years after the variation seen by MACHO. Also shown is the color-magnitude diagram of the star's CCD-quadrant and the excursion of the event.
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$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg11.eps} \end{figure}$	Figure 11: The detection efficiency for unblended ( $\alpha =1$ ) microlensing light curves (10) as a function of $t_{\rm E}$ for LMC (bold line) and SMC (light line) fields. The efficiency applies to a $2500~\rm d$ total observing period. The efficiency used for calculation of the optical depth is the efficiency shown here, multiplied by 0.9 to take into account lensing by binary lenses.
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$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg12.eps} \end{figure}$	Figure 12: The ratio between the summed efficiency, $\epsilon _1(\alpha _1)+\epsilon _2(\alpha _2)$ and the unblended efficiency $\epsilon (\alpha =1)$ for pairs $(\alpha _1,\alpha _2)$ taken from the artificial star analysis of Sect. 3. The ratio is a function of $t_{\rm E}$ . The four curves correspond to the four studied fields, lm009, 019, 034 and 048.
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$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg13.eps}\end{figure}$	Figure 13: The detection efficiency for simple microlensing light curves (10) as a function of u₀ ( top) and of $R_{\rm eros}$ ( bottom) for LMC and SMC events in the range $10~\rm d<t_{\rm E}<200~\rm d$ .
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$\begin{figure} \par\includegraphics[width=7.3cm,clip]{6017fg14.eps}\end{figure}$	Figure 14: The $t_{\rm E}$ distribution ${\rm d}\Gamma /{\rm d}t_{\rm E}$ expected for $1M_\odot$ lenses in a spherically symmetric isothermal halo with core radius $5~{\rm kpc}$ , i.e. the S model used by the MACHO collaboration (Alcock et al. 2000b).
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