All Figures

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{9568fig1.ps}\end{figure}$ Figure 1: Spitzer IRAC 8 $\mu$ m archive image of the GC. Arrows point to the locations of our program stars, the Arches, the Quintuplet, and the Central clusters. North is to the top and east to the left.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{9568fig2.ps}\end{figure}$ Figure 2: K-band spectrum of WR 102ka (blue solid line) together with the best-fitting PoWR model spectrum (red dashed line).
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In the text

$\begin{figure} \par\includegraphics[width=18cm]{9568fig3.ps}\end{figure}$ Figure 3: Contours of constant line emission of helium in the $\log{T_\ast}-\log{R_{\rm t}}$ plane. All other parameters are kept constant ( $\log L_\ast/\rm{\mbox{$L_\odot$ }} = 6.3$ , $\varv _\infty = 400$ km s^-1). Dots indicate the calculated grid models. The interpolated contour lines are labeled with the equivalent width in Å. The solid red lines correspond to the measured value of $W_{\lambda }$ . Panel A): He I $\lambda~2.06$ $\mu$ m; B): He I $\lambda~2.115$ $\mu$ m; C): He II (?) $\lambda~2.19$ $\mu$ m. The contours corresponding to the measured $W_{\lambda }$ are shown together in panel D). The large triangle indicates the adopted final model for WR 102ka (see text).
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm]{9568fig4.ps}\end{figure}$ Figure 4: Spectral energy distribution for WR 102ka. The thick red line gives the reddened model flux (see Table 2 for the parameters). Boxes give observed 2MASS magnitudes (labels). Triangles correspond to the flux in the four IRAC channels, which we extracted from the archival images (see Sect. 3.2 and Table 5).
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm]{9568fig5.ps}\end{figure}$ Figure 5: Features in the WR 102ka spectrum that indicate the possible presence of a companion. Observations (blue ragged line) are compared to the synthetic spectrum for our final model of WR 102ka (red dashed line). The black dotted line represents the spectrum of a hot WNE model, scaled down by a factor of ten. By superimposing both models, the N V (?), He I, and He II lines can be reproduced simultaneously.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm]{9568fig6.ps}\end{figure}$ Figure 6: Spectral energy distribution for WR 102c. The solid line represents the reddened model flux (see Table 2 for the parameters). Boxes give the observed 2MASS magnitudes (labels). Triangles correspond to the flux in the four IRAC channels, which we extracted from the archival images (see Sect. 3.2 and Table 5).
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm]{9568fig7.ps}\end{figure}$ Figure 7: Spitzer IRS SH spectrum of WR 102ka with line identifications. Since the emission region is more extended than the spectrograph slit, the flux is given in terms of surface brightness.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm]{9568fig8.ps}\end{figure}$ Figure 8: Spitzer IRS SH spectrum of WR 102c with line identifications. Since the emission region is more extended than the spectrograph slit, the flux is given in terms of surface brightness.
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In the text

$\begin{figure} \par\includegraphics[width=13.2cm,clip]{9568fig9.ps}\end{figure}$ Figure 9: Spitzer IRAC archive image at 3.6 $\mu \rm {m}$ ( left) and 8 $\mu \rm {m}$ ( right) of the field around WR 102ka. The image size is ${\approx } 2\hbox {$.\mkern -4mu^\prime $ }3\times 1\hbox {$.\mkern -4mu^\prime $ }2$ . North is to the top and east to the left. The white circles have a radius of 10 $^{\prime \prime }$ and are centered on the coordinates of WR 102ka.
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In the text

$\begin{figure} \par\includegraphics[width=13.2cm,clip]{9568fig10.ps}\end{figure}$ Figure 10: Spitzer IRAC archive image at 3.6 $\mu \rm {m}$ ( left) and 8 $\mu \rm {m}$ ( right) of the field around WR 102c. The image size is ${\approx } 2\hbox {$.\mkern -4mu^\prime $ }3\times 1\hbox {$.\mkern -4mu^\prime $ }2$ . North is to the top and east to the left. The white circles have a radius of 10 $^{\prime \prime }$ and are centered on the coordinates of WR 102c.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm]{9568fig11.ps}\end{figure}$ Figure 11: MSX band E image (histogram equalization scale). Positions of nebulae around WR 102ka and WR 102c are indicated by the arrows.
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In the text

$\begin{figure} \par\includegraphics[width=12.6cm,clip]{9568fig12.ps}\end{figure}$ Figure 12: Archival MSX images of the sky field around WR 102ka, from left to right in the A-band (8.28 $\mu$ m), C-band (12.13 $\mu$ m), D-band (14.65 $\mu$ m), and E-band (21.34 $\mu$ m). Each image has a size of ${\approx }4$ $^\prime$ $\times 4$ $^\prime$ . North is to the top and east to the left. The circles have a radius of 20 $^{\prime \prime }$ and are centered on the coordinates of WR 102ka.
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In the text

$\begin{figure} \par\includegraphics[width=12.6cm,clip]{9568fig13.ps}\end{figure}$ Figure 13: Archival MSX images of the sky field around WR 102c, from left to right in the A-band (8.28 $\mu$ m), C-band (12.13 $\mu$ m), D-band (14.65 $\mu$ m), and E-band (21.34 $\mu$ m). Each image has a size of ${\approx }4$ $^\prime$ $\times 4$ $^\prime$ . North is to the top and east to the left. The circles have a radius of 20 $^{\prime \prime }$ and are centered on the coordinates of WR 102c. The Quintuplet cluster can be seen in the lower left part of the images.
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In the text

$\begin{figure} \par\includegraphics[width=15cm]{9568fig14.ps}\end{figure}$ Figure 14: Spectrum of WR 102ka. Boxes, triangles and diamonds correspond to photometric measurements with 2MASS, Spitzer IRAC, and MSX, respectively (cf. Tables 5 and 6). The thin blue line is the spectrum observed with Spitzer IRS. It contains only the flux from those parts of the extended object which have been covered by the spectrograph slit. The thick red line gives the flux of our stellar model. The model of the circumstellar shell adds dust emission. The dash-dotted line represents emission from the inner part of the circumstellar nebula that would be covered by the Spitzer IRS slit, while the long-dashed line contains the simulated emission from the whole object.
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In the text

$\begin{figure} \par\includegraphics[width=15cm]{9568fig15.ps}\end{figure}$ Figure 15: Synthetic stellar spectrum (WNE subtype) of WR 102c (thick red line). Boxes, triangles and diamonds correspond to photometric measurements with 2MASS, Spitzer IRAC, and MSX, respectively (cf. Tables 5 and 6). The thin blue line is the spectrum observed with Spitzer IRS. It contains only the flux from those parts of the extended object which have been covered by the spectrograph slit. The model of the circumstellar shell adds dust emission. The dash-dotted line represents emission from the inner part of the circumstellar nebula that would be covered by the Spitzer IRS slit, while the long-dashed line contains the simulated emission from the whole object.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm]{9568fig16.ps}\end{figure}$ Figure 16: Hertzsprung-Russel diagram with the location of some known LBVs, LBV candidates and our program stars. The thick line indicates the Humphreys-Davidson limit (according Eq. (2) in Lamers & Fitzpatrick 1988). The diamonds marks LBVs with time averaged observations, squares shows the location of the LBV at the maximum, circles at the minimum. The small triangles represent LBV candidates, while the big triangles indicate the locations of WR 102ka and WR 102c. Except of WR 102ka and WR 102c, stellar parameters are from Figer et al. (1998), van Genderen (2001), Najarro (2006), Groh et al. (2006).
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{9568fig17.ps}\end{figure}$ Figure 17: Spitzer MIPS 24 $\mu$ m image of WR 102ka and its peony-shaped nebula. The spatial resolution is $2\hbox{$.\!\!^{\prime\prime}$ }5$ . The nebula has a radius of about 50 $^{\prime \prime }$ . The colors are chosen such that the background appears black. The image is shown on linear scale, as well as the contours. Two central parts of the image are saturated, and are shown in white for cosmetic reasons. North is up, east to the left.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{9568fig1.ps}\end{figure}$	Figure 1: Spitzer IRAC 8 $\mu$ m archive image of the GC. Arrows point to the locations of our program stars, the Arches, the Quintuplet, and the Central clusters. North is to the top and east to the left.
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{9568fig2.ps}\end{figure}$	Figure 2: K-band spectrum of WR 102ka (blue solid line) together with the best-fitting PoWR model spectrum (red dashed line).
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$\begin{figure} \par\includegraphics[width=8.5cm]{9568fig4.ps}\end{figure}$	Figure 4: Spectral energy distribution for WR 102ka. The thick red line gives the reddened model flux (see Table 2 for the parameters). Boxes give observed 2MASS magnitudes (labels). Triangles correspond to the flux in the four IRAC channels, which we extracted from the archival images (see Sect. 3.2 and Table 5).
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$\begin{figure} \par\includegraphics[width=8.5cm]{9568fig6.ps}\end{figure}$	Figure 6: Spectral energy distribution for WR 102c. The solid line represents the reddened model flux (see Table 2 for the parameters). Boxes give the observed 2MASS magnitudes (labels). Triangles correspond to the flux in the four IRAC channels, which we extracted from the archival images (see Sect. 3.2 and Table 5).
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$\begin{figure} \par\includegraphics[width=8.5cm]{9568fig7.ps}\end{figure}$	Figure 7: Spitzer IRS SH spectrum of WR 102ka with line identifications. Since the emission region is more extended than the spectrograph slit, the flux is given in terms of surface brightness.
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$\begin{figure} \par\includegraphics[width=8.5cm]{9568fig8.ps}\end{figure}$	Figure 8: Spitzer IRS SH spectrum of WR 102c with line identifications. Since the emission region is more extended than the spectrograph slit, the flux is given in terms of surface brightness.
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$\begin{figure} \par\includegraphics[width=13.2cm,clip]{9568fig9.ps}\end{figure}$	Figure 9: Spitzer IRAC archive image at 3.6 $\mu \rm {m}$ ( left) and 8 $\mu \rm {m}$ ( right) of the field around WR 102ka. The image size is ${\approx } 2\hbox {$.\mkern -4mu^\prime $ }3\times 1\hbox {$.\mkern -4mu^\prime $ }2$ . North is to the top and east to the left. The white circles have a radius of 10 $^{\prime \prime }$ and are centered on the coordinates of WR 102ka.
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$\begin{figure} \par\includegraphics[width=13.2cm,clip]{9568fig10.ps}\end{figure}$	Figure 10: Spitzer IRAC archive image at 3.6 $\mu \rm {m}$ ( left) and 8 $\mu \rm {m}$ ( right) of the field around WR 102c. The image size is ${\approx } 2\hbox {$.\mkern -4mu^\prime $ }3\times 1\hbox {$.\mkern -4mu^\prime $ }2$ . North is to the top and east to the left. The white circles have a radius of 10 $^{\prime \prime }$ and are centered on the coordinates of WR 102c.
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$\begin{figure} \par\includegraphics[width=8.5cm]{9568fig11.ps}\end{figure}$	Figure 11: MSX band E image (histogram equalization scale). Positions of nebulae around WR 102ka and WR 102c are indicated by the arrows.
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