Astronomy & Astrophysics

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$\begin{figure} \par\includegraphics[width=8.1cm,clip]{0020.f1.eps}\end{figure}$ Figure 1: Azimuthally averaged radial profile of NGC 1399 at $4.5~\mu {\rm m}$ (points). The solid line gives the best fit to the data while the dot-dashed line gives the de Vaucouleurs profile for the galaxy and the dashed line gives the constant value of the background determined from the fit.
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In the text

$\begin{figure} \par\includegraphics[width=7.55cm,clip]{0020.f2.eps}\end{figure}$ Figure 2: Optical HST image (background image) with the 6'' 15 $\mu {\rm m}$ emission map (contours) overlaid for the central region of NGC 1316. The contour levels are 0.3, 0.35, 0.4, 0.6, 0.7, 1.0, 1.2, 4.0, 6.0, 12.0 mJy/pixel. Regions A, B and C show extinction features in the optical image that are traced nicely by the 15 $\mu {\rm m}$ contours.
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In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{0020.f3.eps}\end{figure}$ Figure 3: Optical DSS image (background image) of NGC 5266 with the 6'' 15 $\mu {\rm m}$ emission map (contours) overlaid.
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In the text

$\begin{figure} \par\includegraphics[width=16.1cm,clip]{0020.f4_1.eps}\end{figure}$ Figure 4: SEDs of the early-type galaxies in the sample. The points give the observations within a specific aperture while the lines give the modelled stellar radiation field (the left profile), the FIR dust emission (the right profile) and the total SED (overlaid as the sum of the components). For each galaxy the relative difference between observation and model is given in the bottom panel which is a means to quantify the MIR dust and/or PAH excess between 6 and 18 $\mu {\rm m}$ .
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In the text

$\begin{figure} \addtocounter{figure}{-1} \par\includegraphics[width=16.2cm,clip]{0020.f4_2.eps}\end{figure}$ Figure 4: continued.
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In the text

$\begin{figure} \addtocounter{figure}{-1} \par\includegraphics[width=16.2cm,clip]{0020.f4_3.eps}\end{figure}$ Figure 4: continued.
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In the text

$\begin{figure} \par\includegraphics[height=18cm,width=17.2cm,clip]{0020.f5.eps}\end{figure}$ Figure 5: Azimuthally averaged profiles of the galaxies in the sample. The circles trace the 4.5 $\mu {\rm m}$ flux, the rectangles the 6.7 $\mu {\rm m}$ flux and the stars the 15 $\mu {\rm m}$ flux. The radial distance is measured along the major axis and it is given in kpc to the power of 1/4. In this configuration, a de Vaucouleurs profile would appear as a straight line. The fluxes are given in units of mJy. For clarity reasons the 6.7 $\mu {\rm m}$ profiles of NGC 1052, NGC 5173, NGC 5266, NGC 5363, NGC 5866 are shifted by -0.1, -0.4, -0.3, -0.2, -0.4 dex respectively while the 15 $\mu {\rm m}$ profiles of NGC 185, NGC 1052, NGC 3928, NGC 5018, NGC 5173, NGC 5266, NGC 5363, NGC 5866 are shifted by -0.4, -0.8, +0.5, -0.3, -0.9, -0.7, -0.4, -0.7 dex respectively.
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In the text

$\begin{figure} \par\includegraphics[height=18cm,width=17.2cm,clip]{0020.f6.eps}\end{figure}$ Figure 6: Azimuthally averaged MIR flux ratio profiles. The $6.7~\mu {\rm m} / 4.5~\mu {\rm m}$ ratio is plotted with boxes while the $15~\mu {\rm m} / 4.5~\mu {\rm m}$ ratio is plotted with stars. The arrows on the right side of the plot indicate the value of the flux ratios of $6.7~\mu {\rm m} / 4.5~\mu {\rm m}$ and $15~\mu {\rm m} / 4.5~\mu {\rm m}$ for a black-body of a temperature of 3000 K for which the ratio $6.7~\mu {\rm m} / 4.5~\mu {\rm m}$ is 0.55 (indicated by the solid arrow) while the ratio $15~\mu {\rm m} / 4.5~\mu {\rm m}$ is 0.14 (indicated by the open arrow). The radial distance is given in kpc to the power of 1/4.
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In the text

$\begin{figure} \par\includegraphics[width=8.1cm,clip]{0020.f7.eps}\end{figure}$ Figure 7: The $F_\nu(6.7~\mu {\rm m})/F_\nu(15~\mu {\rm m})$ ratio versus the $F_\nu(12~\mu {\rm m})$ / $F_\nu(25~\mu {\rm m})$ ratio for the Dale et al. (2000) sample of normal star-forming galaxies (solid circles), the Roussel et al. (2001) sample of spiral galaxies (open squares) and the early-type sample of galaxies from this paper (red triangles). The cross on the top left part of the diagram indicates a typical error bar associated with the early-type galaxies analyzed in this work.
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In the text

$\begin{figure} \par\includegraphics[width=8.1cm,clip]{0020.f8.eps}\end{figure}$ Figure 8: The $F_\nu(6.7~\mu {\rm m})/F_\nu(15~\mu {\rm m})$ ratio versus the $F_\nu(60~\mu {\rm m})$ / $F_\nu(100~\mu {\rm m})$ ratio. The symbol coding is the same as in Fig. 7. The cross on the top right part of the diagram indicates a typical error bar associated with the early-type galaxies analyzed in this work.
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In the text

$\begin{figure} \par\includegraphics[width=8.4cm,clip]{0020.f9.eps}\end{figure}$ Figure 9: The SED of the radio galaxy NGC 4486 (M87). The points are fitted with three components: a stellar radiation field modelled by PÉGASE, a modified black-body law representing dust peaking in the FIR and a power-law describing the synchrotron emission. On top of these three different component the composite spectrum is shown. The bottom panel in each plot shows the relative difference of the observations from the modelled spectrum.
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In the text

$\begin{figure} \par\includegraphics[width=7.6cm,clip]{0020.f10.eps}\end{figure}$ Figure 10: Major-axis profiles of the MIR emission (6.7 $\mu {\rm m}$ and 15 $\mu {\rm m}$ shown as dashed and solid line respectively) for the edge-on lenticular galaxy NGC 5866. The emission peaks at the nucleus and secondary maxima at $\simeq$ 4 kpc either side of the center are present.
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In the text

$\begin{figure} \par\includegraphics[width=13cm,clip]{0020.f11.eps}\end{figure}$ Figure A.1: Mid-IR maps for NGC 185 (left) and NGC 205 (right). The top panels show the $4.5~\mu {\rm m}$ contours overlaid on the optical images of the galaxies. The middle panels show the $6.7~\mu {\rm m}$ maps and the bottom panels show the $15~\mu {\rm m}$ maps with the basic contours of these maps overlaid in order to emphasize the shape of the MIR images. For NGC 185 the contour levels are 0.3, 0.4, 0.6, 0.8, 1.0, 1.2, 1.3, 1.4, 1.5 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.2, 1.3, 1.4, 1.5, 1.7 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.2 mJy/pixel for the $15~\mu {\rm m}$ map (bottom). For NGC 205 the contour levels are 0.4, 0.5, 0.6, 0.8, 1.0, 1.3, 1.8 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1.0, 1.3, 1.7 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom).

In the text

$\begin{figure} \par\includegraphics[width=13cm,clip]{0020.f12.eps}\end{figure}$ Figure A.2: Same as in Fig. A.1. but for the galaxies NGC 1052 (left) and NGC 1316 (right). For NGC 1052 the contour levels are 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.8, 2.4, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 12.0, 14.0, 16.0, 18.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.1, 0.3, 0.6, 1.0, 2.0, 4.0, 10.0, 20.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.6, 1.0, 2.0, 4.0, 10., 20., 30., 40., 50.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom). For NGC 1316 the contour levels are 0.5, 1.0, 2.0, 3.0, 5.0, 8.0, 12.0, 20.0, 30.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.3, 0.6, 1.0, 1.5, 2.0, 3.0, 5.0, 10.0, 15.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.2, 0.5, 1.0, 1.5, 2.0, 3.0, 5.0, 10.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom).

In the text

$\begin{figure} \par\includegraphics[width=13cm,clip]{0020.f13.eps}\end{figure}$ Figure A.3: Same as in Fig. A.1. but for the galaxies NGC 1399 (left) and NGC 2300 (right). For NGC 1399 the contour levels are 0.3, 0.5, 1.0, 2.0, 4.0, 10.0, 16.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.2, 0.3, 0.5, 1.0, 2.0, 4.0, 10.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.4, 0.6, 1.0, 2.0, 4.0, 10.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom). For NGC 2300 the contour levels are 0.3, 0.5, 1.0, 2.0, 4.0, 10.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.2, 0.3, 0.5, 1.0, 2.0, 4.0, 6.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.3, 0.5, 0.7, 1.0, 1.5, 2.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom).

In the text

$\begin{figure} \par\includegraphics[width=13cm,clip]{0020.f14.eps}\end{figure}$ Figure A.4: Same as in Fig. A.1. but for the galaxies NGC 3928 (left) and NGC 4278 (right). For NGC 3928 the contour levels are 0.5, 0.7, 1.0, 1.5, 2.0, 3.0, 4.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.3, 0.5, 1.0, 2.0, 3.0, 5.0, 10.0, 15.0, 20.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.5, 1.0, 2.0, 3.0, 5.0, 10.0, 15.0, 20.0, 23.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom). For NGC 4278 the contour levels are 0.3, 0.5, 1.0, 2.0, 5.0, 10.0, 15.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.3, 0.5, 1.0, 2.0, 5.0, 10.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.2, 0.3, 0.5, 1.0, 2.0, 4.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom).

In the text

$\begin{figure} \par\includegraphics[width=13cm,clip]{0020.f15.eps}\end{figure}$ Figure A.5: Same as in Fig. A.1. but for the galaxies NGC 4374 (left) and NGC 4473 (right). For NGC 4374 the contour levels are 0.6, 1.0, 2.0, 5.0, 10.0, 15.0, 20.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.6, 1.0, 2.0, 5.0, 10.0, 15.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.5, 0.7, 1.0, 1.5, 2.0, 3.0, 5.0, 6.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom). For NGC 4473 the contour levels are 0.7, 1.0, 1.5, 3.0, 5.0, 10.0, 15.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.3, 0.5, 0.7, 1.0, 1.5, 3.0, 5.0, 7.0, 9.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.7, 1.0, 1.5, 3.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom).

In the text

$\begin{figure} \par\includegraphics[width=13.4cm,clip]{0020.f16.eps}\end{figure}$ Figure A.6: Same as in Fig. A.1. but for the galaxies NGC 4486 (left) and NGC 4649 (right). For NGC 4486 the contour levels are 7.0, 8.0, 9.0, 10.0, 12.0, 15.0, 17.0, 19.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 12.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom). For NGC 4649 the contour levels are 1.0, 1.5, 2.0, 3.0, 5.0, 8.0, 10.0, 15.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.7, 1.0, 1.5, 2.0, 3.0, 5.0, 8.0, 10.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 1.0, 1.5, 2.0, 3.0, 4.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom).

In the text

$\begin{figure} \par\includegraphics[width=13cm,clip]{0020.f17.eps}\end{figure}$ Figure A.7: Same as in Fig. A.1. but for the galaxies NGC 5018 (left) and NGC 5102 (right). For NGC 5018 the contour levels are 0.7, 1.0, 2.0, 4.0, 8.0, 15.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.5, 1.0, 2.0, 4.0, 8.0, 12.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.5, 1.0, 2.0, 4.0, 6.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom). For NGC 5102 the contour levels are 0.5, 0.7, 1.0, 2.0, 4.0, 7.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.2, 0.4, 0.7, 1.0, 2.0, 4.0, 7.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.4, 0.7, 1.0, 2.0, 4.0, 7.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom).

In the text

$\begin{figure} \par\includegraphics[width=13cm,clip]{0020.f18.eps}\end{figure}$ Figure A.8: Same as in Fig. A.1. but for the galaxies NGC 5173 (left) and NGC 5266 (right). For NGC 5173 the contour levels are 0.3, 0.5, 1.0, 2.0, 3.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.5, 1.0, 2.0, 3.0, 3.7 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.6, 1.0, 2.0, 3.0, 3.7 mJy/pixel for the $15~\mu {\rm m}$ map (bottom). For NGC 5266 the contour levels are 0.3, 0.5, 0.7, 1.0, 2.0, 3.0, 6.0, 10.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.5, 0.7, 1.0, 2.0, 3.0, 6.0, 10.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.7, 1.0, 2.0, 3.0, 4.0, 6.0, 8.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom).

In the text

$\begin{figure} \par\includegraphics[width=13cm,clip]{0020.f19.eps}\end{figure}$ Figure A.9: Same as in Fig. A.1. but for the galaxies NGC 5363 (left) and NGC 5866 (right). For NGC 5363 the contour levels are 1.0, 1.5, 2.0, 3.0, 5.0, 10.0, 13.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.7, 1.0, 1.5, 2.0, 3.0, 5.0, 10.0, 15.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.8, 2.0, 5.0, 10.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom). For NGC 5866 the contour levels are 0.5, 1.0, 2.0, 4.0, 8.0, 10.0 mJy/pixel for the 4.5 $\mu {\rm m}$ map (top), 0.3, 0.5, 1.0, 2.0, 4.0, 8.0, 12.0 mJy/pixel for the $6.7~\mu {\rm m}$ map (middle) and 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, 12.0 mJy/pixel for the $15~\mu {\rm m}$ map (bottom).

In the text

$\begin{figure} \par\includegraphics[width=8.1cm,clip]{0020.f1.eps}\end{figure}$	Figure 1: Azimuthally averaged radial profile of NGC 1399 at $4.5~\mu {\rm m}$ (points). The solid line gives the best fit to the data while the dot-dashed line gives the de Vaucouleurs profile for the galaxy and the dashed line gives the constant value of the background determined from the fit.
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$\begin{figure} \par\includegraphics[width=7.55cm,clip]{0020.f2.eps}\end{figure}$	Figure 2: Optical HST image (background image) with the 6'' 15 $\mu {\rm m}$ emission map (contours) overlaid for the central region of NGC 1316. The contour levels are 0.3, 0.35, 0.4, 0.6, 0.7, 1.0, 1.2, 4.0, 6.0, 12.0 mJy/pixel. Regions A, B and C show extinction features in the optical image that are traced nicely by the 15 $\mu {\rm m}$ contours.
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$\begin{figure} \par\includegraphics[width=8.2cm,clip]{0020.f3.eps}\end{figure}$	Figure 3: Optical DSS image (background image) of NGC 5266 with the 6'' 15 $\mu {\rm m}$ emission map (contours) overlaid.
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$\begin{figure} \addtocounter{figure}{-1} \par\includegraphics[width=16.2cm,clip]{0020.f4_2.eps}\end{figure}$	Figure 4: continued.
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$\begin{figure} \par\includegraphics[width=8.1cm,clip]{0020.f8.eps}\end{figure}$	Figure 8: The $F_\nu(6.7~\mu {\rm m})/F_\nu(15~\mu {\rm m})$ ratio versus the $F_\nu(60~\mu {\rm m})$ / $F_\nu(100~\mu {\rm m})$ ratio. The symbol coding is the same as in Fig. 7. The cross on the top right part of the diagram indicates a typical error bar associated with the early-type galaxies analyzed in this work.
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$\begin{figure} \par\includegraphics[width=7.6cm,clip]{0020.f10.eps}\end{figure}$	Figure 10: Major-axis profiles of the MIR emission (6.7 $\mu {\rm m}$ and 15 $\mu {\rm m}$ shown as dashed and solid line respectively) for the edge-on lenticular galaxy NGC 5866. The emission peaks at the nucleus and secondary maxima at $\simeq$ 4 kpc either side of the center are present.
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