All Figures

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{gk031_f1.eps}\end{figure}$ Figure 1: Top: ACS image of Abell 1689 plus thumbnails of the five brightest UCD candidates, numbered by decreasing luminosity according to Table 1. The thumbnail width is 7 $^{\prime \prime }$ . Bottom: CMD of UCD candidates in Abell 1689. Circles: Photometric redshift $z_{\rm phot}<0.5$ . Crosses: $z_{\rm phot}>0.5$ . The dashed vertical lines indicate the colour range of Fornax UCDs, the vertical tick their apparent luminosities if shifted to A1689's distance (Mieske et al. 2004a,b). The approximate location in the CMD of M 32 at A1689's distance is indicated by the cross (Mateo 1998).
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{gk031_f2a.ps}\par\includegraphics[width=8.5cm,clip]{gk031_f2b.ps}\end{figure}$ Figure 2: Top panel: morphological comparison between (from left to right): CG $_{\rm A1689,1}$ (i=22.2 mag); M 32 modelled according to the fit by Graham (2002), projected to A1689's distance and seeing convolved (i = 22.4 mag); CG $_{\rm A1689,2}$ (i=22.8 mag). Bottom panel: an unresolved point source (i=22.4 mag). The image excerpts have the same intensity cuts and are taken from deep ACS i-band exposures of Abell 1689. There is a higher noise level for the lower image because the point source originally is about 1.5 mag fainter and was scaled up to fall in the luminosity range of the M 32-like objects.
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In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{gk031_f3.eps}\end{figure}$ Figure 3: Wavelength calibrated spectra of the five UCD candidates, ordered from top to bottom by decreasing i luminosity. The spectra are not flux-calibrated. Candidates 1 and 3 have spectroscopic redshifts consistent with A1689. The H&K break is at about 4700 Å for candidate 1 and 4800 Å for candidate 3.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{gk031_f4.eps}\end{figure}$ Figure 4: Comparison of surface brightness (SB) profiles, with scale 0.05 $\hbox {$^{\prime \prime }$ }$ /pixel, or 155 pc/pixel at Abell 1689's distance. Upper panel: CG $_{\rm A1689,1}$ (filled circles), CG $_{\rm A1689,2}$ (filled triangles), M 32's profile from the fit by Graham (2002), projected to A1689's distance and PSF convolved (open hexagons). Lower panel: the three SB profiles from the upper panel normalised to the same peak intensity plus the normalised PSF profile (Moffat profile with 0.095 $\hbox {$^{\prime \prime }$ }$ FWHM). The solid line is a PSF convolved Sersic profile with $r_{\rm eff}=$ 300 pc and n=1.85.
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In the text

$\begin{figure} \par\includegraphics[width=7.7cm,clip]{gk031_f5.eps}\end{figure}$ Figure 5: Size-luminosity distribution of normal dwarf galaxies and UCD candidates in Abell 1689. SExtractor FWHM is plotted vs. i-band luminosity for sources with $z_{\rm phot}<$ 0.5 in the indicated magnitude range. The PSF-FWHM is about 0.10 $\hbox {$^{\prime \prime }$ }$ . The dots are the unresolved UCD candidates, defined by a star-classifier larger than 0.6 (see Mieske et al. 2004b). The asterisks indicate the resolved dwarf galaxy candidates, defined as having SExtractor star-classifier smaller than 0.6. The larger filled circles indicate the two confirmed M 32 twins. The open circles indicate galaxies with a measured spectroscopic redshift (Czoske 2004), double circles are those with 0.16<z<0.22 (redshift range of Abell 1689).
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In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{gk031_f3.eps}\end{figure}$	Figure 3: Wavelength calibrated spectra of the five UCD candidates, ordered from top to bottom by decreasing i luminosity. The spectra are not flux-calibrated. Candidates 1 and 3 have spectroscopic redshifts consistent with A1689. The H&K break is at about 4700 Å for candidate 1 and 4800 Å for candidate 3.
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