All Figures

$\begin{figure} \par\includegraphics[height=5cm,width=5cm,clip]{10159ph1.eps}\inc... ...159ph2.eps}\includegraphics[height=5cm,width=5cm,clip]{10159q2.eps} \end{figure}$ Figure 1: PAH1 ( left, 0 $.\!\!^{\prime\prime}$ 127 plate scale per pixel), PAH2 ( centre, 0 $.\!\!^{\prime\prime}$ 127 plate scale per pixel), and Q2 ( right, 0 $.\!\!^{\prime\prime}$ 075 plate scale per pixel) VISIR images of the environment of SGR 1806-20 (white X point) obtained in June 2006. A is LBV 1806-20, B is a WC9 star, C is an O/B supergiant, and 5 is a red giant (Eikenberry et al. 2004; Figer et al. 2005). An ellipse pattern surrounds G, the hottest part of the gas and dust cloud in which all stars are embedded. We detected it in PAH2 and in Q2.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[height=4cm,width=7cm,clip]{10159tcl.ps} \end{figure}$ Figure 2: Three-colour image of the environment of SGR 1806-20 (white X point) done with images of June 2006; PAH1 is in blue, PAH2 in green, and Q2 in red. Q2 image was rescaled to a 0 $.\!\!^{\prime\prime}$ 127 plate scale. The cloud detected with VISIR appears to be splitted into several components, which shows that its temperature is not homogeneous, the cloud being hotter in the centre of the massive star cluster.
Open with DEXTER

In the text

$\begin{figure} \par\begin{tabular}{cc} \includegraphics[width=6cm,height=4.5cm]... ...ludegraphics[width=6cm,height=4.5cm]{10159ch4.eps}\\ \end{tabular} \end{figure}$ Figure 3: IRAC 3.6 $\mu$ m ( top left), 4.5 $\mu$ m ( top right), 5.8 $\mu$ m ( bottom left), and 8.0 $\mu$ m ( bottom right) images of the environment of SGR 1806-20 (white X point). The field of view is about 79 $\hbox {$^{\prime \prime }$ }$ $\times$ 71 $\hbox {$^{\prime \prime }$ }$ and the plate scale is 1 $.\!\!^{\prime\prime}$ 2 per pixel. We point out that the position of SGR 1806-20 is 2 $.\!\!^{\prime\prime}$ 95 away from the point source located south east of the white X point, which - considering the 0 $.\!\!^{\prime\prime}$ 5 astrometric accuracy of the Spitzer telescope - excludes an association with SGR 1806-20.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{10159mps.eps} \end{figure}$ Figure 4: MIPS 24 $\mu$ m image of the environment of SGR 1806-20 (black X point). We also superimposed the MIPS contour plot to stress the differences in luminosity. We clearly see the gas and dust cloud in which all the stars are embedded, and it is likely the birth site of the massive star cluster. It appears that LBV 1806-20 (A) is located in a less dense and colder zone of the cloud than the WC9 star (B) and the O/B supergiant star (C), which explains that its intrinsic absorption is lower. Moreover, the central part of the cloud - which appears saturated in this image as it is too hot with respect to the MIPS level of saturation - corresponds to the region detected with VISIR. The field of view is 94 $\hbox {$^{\prime \prime }$ }$ $\times$ 67 $\hbox {$^{\prime \prime }$ }$ and the plate scale is 2 $.\!\!^{\prime\prime}$ 5 per pixel.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[angle=270,width=8.3cm,clip]{10159lbv.ps}\par... ...wc9.ps}\par\includegraphics[angle=270,width=8.3cm,clip]{10159ob.ps} \end{figure}$ Figure 5: NIR to MIR-fitted SEDs of LBV 1806-20, the WC9 star, and the O/B supergiant. For LBV 1806-20 and the WC9 star, we also add parts of their emission due to the stellar and the dust components. We used the MIR data from the VISIR observations we performed, the GLIMPSE survey, as well as the NIR data from EML04. The silicate absorption feature at 9.7 $\mu$ m comes from the use of the Lutz's interstellar extinction law, in which it is included.
Open with DEXTER

In the text