All Figures

$\begin{figure} \par\includegraphics[scale=0.42,clip]{H4459F1.eps} \end{figure}$ Figure 1: H $\alpha$ image of the Eagle nebula taken on the 1st January 2001 with the Nordic Optical Telescope (NOT) using the ALFOSC instrument, La Palma. The footprint of the ISOCAM-CVF field is outlined by the white square. The three pillars can clearly be seen in this image running north-west to south-east and will be referred to as $\Pi _1$ , $\Pi _2$ and $\Pi _3$ respectively.
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In the text

$\begin{figure} \par {\hspace*{7mm}\includegraphics[scale=0.4,clip]{H4459F2.eps}\hspace*{7mm}} \par\includegraphics[scale=0.5,clip]{H4459F3.eps} \end{figure}$ Figure 2: Left: Broadband infrared image of the Eagle nebula taken by ISOCAM over the 5.1-17 $\mu$ m wavelength range. The brightest regions are the head of $\Pi _1$ (labelled D) and the ridge between the base of $\Pi _1$ and $\Pi _2$ (labelled B), with the trunk like structure of $\Pi _1$ weakly visible and $\Pi _2$ and $\Pi _3$ visible only as a diffuse region of emission. Another feature to note is a region of bright emission to the NE of $\Pi _1$ (labelled A, and referred to in this paper as "Pilbratt's blob'') comparable in strength to the emission from the head of $\Pi _1$ and the ridge. This region of bright was detected by Pi98 in their LW3 image, but not detected in the shorter wavelength LW2 image. In the CVF mode a complete spectrum is recorded for each pixel over the $\sim$ 5-17 $\mu$ m range. Right: CVF spectra of four regions of particular interest. Clockwise, Pilbratt's blob (A), the ridge connecting $\Pi _1$ and $\Pi _2$ (B), ionised region between tip of $\Pi _1$ and ionising source and tip of $\Pi _1$ (C), and finally the bright emission detected at the tip of $\Pi _1$ (D).
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In the text

$\begin{figure} \par\includegraphics[scale=0.65,clip]{H4459F4.eps} \end{figure}$ Figure 3: The image above is a closeup of the blended UIB 12.7 $\mu$ m and the [NeII] 12.8 $\mu$ m lines taken from the location labelled D in Fig. 2. This image clearly shows the blended feature centred at 12.8 $\mu$ m, as well as a slight shoulder located on the blue side of the blended feature, due to weak UIB 12.7 $\mu$ m emission.
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In the text

$\begin{figure} \par\includegraphics[width=15.5cm,clip]{H4459F5.eps} \end{figure}$ Figure 4: Spectra taken from $6^{\prime \prime } \times 6^{\prime \prime }$ pixel field-of-view centred at the locations denoted by the labels A ( top panel), B ( centre panel), and D ( bottom panel) in Fig. 2.
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In the text

$\begin{figure} \par\includegraphics[width=17cm,clip]{H4459F6.eps} \end{figure}$ Figure 5: Maps of the spatial brightness distribution of the decomposed ISOCAM-CVF spectra. The difference between the UIB and fine-structure lines can clearly be seen, with all of the UIB emission being confined to the pillar regions and the fine-structure lines being much more diffuse and located round the tips of $\Pi _1$ and $\Pi _2$ and the region between the two pillars.
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In the text

$\begin{figure} \par\includegraphics[width=6.1cm,clip]{H4459F7.eps}\hspace*{1mm} \includegraphics[width=5.68cm,clip]{H4459F8.eps} \end{figure}$ Figure 6: Left: Image of the 7.7 $\mu$ m UIB produced from the decomposition of the ISOCAM-CVF spectra. Right: The LW2 ISOCAM image of a 4 $^{\prime }\times 4^{\prime }$ FOV the pillar structures in M 16 taken from observations by Pilbratt et al. (1998; see paper for observation details).
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In the text

$\begin{figure} \par\includegraphics[width=6.5cm,clip]{H4459F9.eps}\hspace*{1mm} \includegraphics[width=6.1cm,clip]{H4459F10.eps} \end{figure}$ Figure 7: Left: Image of the 13.5-15 $\mu$ m continuum emission. Right: The LW3 ISOCAM image of a $4\hbox{$.\mkern-4mu^\prime$ }8~\times~4\hbox{$.\mkern-4mu^\prime$ }8$ field the pillar structures in M 16 taken from observations by Pilbratt et al. (1998; see paper for observation details). These two independent images confirm the reality of "Pilbratt's blob''.
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In the text

$\begin{figure} \par\includegraphics[width=7.15cm,clip]{H4459F11.ps}\includegraph... ...m}\includegraphics[width=7.15cm,clip]{H4459F13.ps}\hspace*{3.6cm}}\end{figure}$ Figure 8: Upper left: SCUBA 450 $\mu$ m images of the pillar structures in M 16 overlaid with the contoured emission of the 7.7 $\mu$ m PAH feature. Upper right: VLA image of M 16 again overlaid with UIB 7.7 $\mu$ m emission. Expanded region of the VLA emission on the right. Lower bottom: ¹²CO ( $\emph {J}=1{-}0$ ) map (Pound, private communication) shows the distribution of molecular gas. (Contours levels are set at 10% of the peak emission beginning at 0.4 Jy.)
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In the text

$\begin{figure} \par\includegraphics[scale=0.4,clip]{H4459F14.eps} \end{figure}$ Figure 9: Ratio maps of [NeIII] 15.6 $\mu$ m/[NeII] 12.8 $\mu$ m. The pillars can be seen silhouetted against the bright HII region. The colour bar to the right of the map displays the ratio value across the field, ranging from 0.4 (black) to 1.6 (white).
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In the text

$\begin{figure} \par\includegraphics[scale=0.65,clip]{H4459F15.eps} \end{figure}$ Figure 10: Results obtained from CLOUDY for the [NeIII]/[NeII] ratio for different values of ionising photons on the surface of the pillars and the hydrogen density, n (H₂ cm³). The ratio obtained from the decomposition of the CVF data is represented by a triangle.
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In the text

$\begin{figure} \par\includegraphics[scale=0.42,clip]{H4459F1.eps} \end{figure}$	Figure 1: H $\alpha$ image of the Eagle nebula taken on the 1st January 2001 with the Nordic Optical Telescope (NOT) using the ALFOSC instrument, La Palma. The footprint of the ISOCAM-CVF field is outlined by the white square. The three pillars can clearly be seen in this image running north-west to south-east and will be referred to as $\Pi _1$ , $\Pi _2$ and $\Pi _3$ respectively.
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$\begin{figure} \par\includegraphics[scale=0.65,clip]{H4459F4.eps} \end{figure}$	Figure 3: The image above is a closeup of the blended UIB 12.7 $\mu$ m and the [NeII] 12.8 $\mu$ m lines taken from the location labelled D in Fig. 2. This image clearly shows the blended feature centred at 12.8 $\mu$ m, as well as a slight shoulder located on the blue side of the blended feature, due to weak UIB 12.7 $\mu$ m emission.
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$\begin{figure} \par\includegraphics[width=15.5cm,clip]{H4459F5.eps} \end{figure}$	Figure 4: Spectra taken from $6^{\prime \prime } \times 6^{\prime \prime }$ pixel field-of-view centred at the locations denoted by the labels A ( top panel), B ( centre panel), and D ( bottom panel) in Fig. 2.
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$\begin{figure} \par\includegraphics[width=17cm,clip]{H4459F6.eps} \end{figure}$	Figure 5: Maps of the spatial brightness distribution of the decomposed ISOCAM-CVF spectra. The difference between the UIB and fine-structure lines can clearly be seen, with all of the UIB emission being confined to the pillar regions and the fine-structure lines being much more diffuse and located round the tips of $\Pi _1$ and $\Pi _2$ and the region between the two pillars.
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$\begin{figure} \par\includegraphics[width=6.1cm,clip]{H4459F7.eps}\hspace*{1mm} \includegraphics[width=5.68cm,clip]{H4459F8.eps} \end{figure}$	Figure 6: Left: Image of the 7.7 $\mu$ m UIB produced from the decomposition of the ISOCAM-CVF spectra. Right: The LW2 ISOCAM image of a 4 $^{\prime }\times 4^{\prime }$ FOV the pillar structures in M 16 taken from observations by Pilbratt et al. (1998; see paper for observation details).
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$\begin{figure} \par\includegraphics[width=6.5cm,clip]{H4459F9.eps}\hspace*{1mm} \includegraphics[width=6.1cm,clip]{H4459F10.eps} \end{figure}$	Figure 7: Left: Image of the 13.5-15 $\mu$ m continuum emission. Right: The LW3 ISOCAM image of a $4\hbox{$.\mkern-4mu^\prime$ }8~\times~4\hbox{$.\mkern-4mu^\prime$ }8$ field the pillar structures in M 16 taken from observations by Pilbratt et al. (1998; see paper for observation details). These two independent images confirm the reality of "Pilbratt's blob''.
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$\begin{figure} \par\includegraphics[scale=0.4,clip]{H4459F14.eps} \end{figure}$	Figure 9: Ratio maps of [NeIII] 15.6 $\mu$ m/[NeII] 12.8 $\mu$ m. The pillars can be seen silhouetted against the bright HII region. The colour bar to the right of the map displays the ratio value across the field, ranging from 0.4 (black) to 1.6 (white).
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$\begin{figure} \par\includegraphics[scale=0.65,clip]{H4459F15.eps} \end{figure}$	Figure 10: Results obtained from CLOUDY for the [NeIII]/[NeII] ratio for different values of ionising photons on the surface of the pillars and the hydrogen density, n (H₂ cm³). The ratio obtained from the decomposition of the CVF data is represented by a triangle.
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