All Figures

$\begin{figure} \par\includegraphics[width=11cm,clip]{4786fi01.ps} \end{figure}$ Figure 1: The field of HB 21 in the H $\alpha +[$ N II] filter. The shadings run linearly from 7 to 45 $\times$ 10^-17 erg s^-1 cm^-2 arcsec^-2. The long rectangles mark the locations where long-slit spectra were obtained. The image has been smoothed to suppress the residuals from the imperfect continuum subtraction.
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In the text

$\begin{figure} \par\includegraphics[width=11cm,clip]{4786fi02.ps} \end{figure}$ Figure 2: Areas of strong sulfur emission [S II] are good candidates for an association with the remnant because the sulfur filter suppresses the background emission, as well as the emission from HII regions. The image has been smoothed to suppress the residuals from the imperfect continuum subtraction, while the shadings run linearly from 1 to 9 $\times$ 10^-17 erg s^-1 cm^-2 arcsec^-2.
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In the text

$\begin{figure} \par\includegraphics[width=11cm,clip]{4786fi03.ps} \end{figure}$ Figure 3: The field of HB 21 in the [S II] filter (background image) with the 4850 MHz contours overlaid. The contours scale linearly, every 0.022 Jy/beam, from 0.01 to 0.14 Jy/beam (Condon et al. 1994). The letters A to D refer to areas of emission that may be associated to the remnant, while the ellipse drawn encompasses the majority of the radio and optical emission.
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In the text

$\begin{figure} \par\includegraphics[width=7cm,clip]{4786fi04.ps} \end{figure}$ Figure 4: Typical long-slit spectra from locations I, II, and VII in the area of the remnant HB 21. More details can be found in Sect. 3.2 and Table 3.
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In the text

$\begin{figure} \par\includegraphics[width=12cm,clip]{4786fi05.ps} \end{figure}$ Figure 5: The field of HB 21 in the [S II] filter (background image) with the 60 $\mu$ m IRAS/HiRes contours overlaid. The contours show the emission from 2 to 10 MJy/sr on 10 levels. The slit projections on the sky are shown for comparison purposes.
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In the text

$\begin{figure} \par\includegraphics[width=12cm,clip]{4786fi06.ps} \end{figure}$ Figure 6: This figure shows an RG composite based on the H $\alpha +[$ N II] (greenish) and [S II] (reddish) low ionization images. The majority of the diffuse emission appears to emit mainly in the H $\alpha$ and [N II] emission lines. The slit projections on the sky are also shown for comparison purposes.
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In the text

$\begin{figure} \par\includegraphics[width=11cm,clip]{4786fi01.ps} \end{figure}$	Figure 1: The field of HB 21 in the H $\alpha +[$ N II] filter. The shadings run linearly from 7 to 45 $\times$ 10^-17 erg s^-1 cm^-2 arcsec^-2. The long rectangles mark the locations where long-slit spectra were obtained. The image has been smoothed to suppress the residuals from the imperfect continuum subtraction.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=11cm,clip]{4786fi02.ps} \end{figure}$	Figure 2: Areas of strong sulfur emission [S II] are good candidates for an association with the remnant because the sulfur filter suppresses the background emission, as well as the emission from HII regions. The image has been smoothed to suppress the residuals from the imperfect continuum subtraction, while the shadings run linearly from 1 to 9 $\times$ 10^-17 erg s^-1 cm^-2 arcsec^-2.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=11cm,clip]{4786fi03.ps} \end{figure}$	Figure 3: The field of HB 21 in the [S II] filter (background image) with the 4850 MHz contours overlaid. The contours scale linearly, every 0.022 Jy/beam, from 0.01 to 0.14 Jy/beam (Condon et al. 1994). The letters A to D refer to areas of emission that may be associated to the remnant, while the ellipse drawn encompasses the majority of the radio and optical emission.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=7cm,clip]{4786fi04.ps} \end{figure}$	Figure 4: Typical long-slit spectra from locations I, II, and VII in the area of the remnant HB 21. More details can be found in Sect. 3.2 and Table 3.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=12cm,clip]{4786fi05.ps} \end{figure}$	Figure 5: The field of HB 21 in the [S II] filter (background image) with the 60 $\mu$ m IRAS/HiRes contours overlaid. The contours show the emission from 2 to 10 MJy/sr on 10 levels. The slit projections on the sky are shown for comparison purposes.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=12cm,clip]{4786fi06.ps} \end{figure}$	Figure 6: This figure shows an RG composite based on the H $\alpha +[$ N II] (greenish) and [S II] (reddish) low ionization images. The majority of the diffuse emission appears to emit mainly in the H $\alpha$ and [N II] emission lines. The slit projections on the sky are also shown for comparison purposes.
Open with DEXTER