All Figures

$\begin{figure} \par\epsfig{figure=h4147f1.ps,width=14.0cm,clip=} \end{figure}$ Figure 1: Adaptively-smoothed greyscale Chandra ACIS image of M 83, in the 0.3-8.0 keV band (square-root scale, arbitrary zeropoint). The D₂₅ ellipse and the S3 chip boundaries are overplotted. The region inside the central square is shown in greater detail in Fig. 2.
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=fig2eps.eps,width=7cm,clip=} \end{figure}$ Figure 2: Close-up view of the starburst nucleus. The source numbers refer to Table A.1. North is up, and East is left. (This figure is available in color in electronic form.)
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f3.ps,width=7.2cm,clip=} \end{figure}$ Figure 3: A "true-colour'' Chandra ACIS image of M 83 shows about 130 discrete sources (down to a luminosity of $\approx 3 \times 10^{36}$ erg s^-1 for the assumed distance of 3.7 Mpc) and diffuse emission in the starburst nucleus and along the spiral arms. The colors are: red for 0.3-1.0 keV; green for 1.0-2.0 keV; blue for 2.0-8.0 keV. The size of the image is $12\hbox {$^\prime $ }\times 10\hbox {$^\prime $ }$ . North is up, East is left. (This figure is available in color in electronic form.)
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f4.ps,width=5cm,angle=270,clip=} \end{figure}$ Figure 4: Background subtracted X-ray spectral distribution (crosses), together with the best fitting absorbed power law model (histogram, upper panel), for source No. 63, coincident with the optical nucleus of M 83. The ratio of data versus model is plotted in the lower panel. Error bars along the Y axis show statistical uncertainties, those along the X axis represent the width of the energy bins. The X-ray spectrum is well fitted by an absorbed powerlaw with $\Gamma \approx 1.45$ (fit parameters in Table B.1).
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f5.ps,width=5cm,angle=270,clip=}\\ \vspace*{0.35cm} \epsfig{figure=h4147f6.ps,width=5cm,angle=270,clip=} \end{figure}$ Figure 5: The spectra of the two brightest supersoft sources (top: No. 68; bottom: No. 96); see Table B.2 for the fit parameters.
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f7.ps,width=5cm,angle=270,clip=}\\ \vspace*{0.35cm} \epsfig{figure=h4147f8.ps,width=5cm,angle=270,clip=} \end{figure}$ Figure 6: Spectra of sources No. 3 (top) and 27 (bottom) together with a best-fitting absorbed power law model with emission lines (see Table B.3).
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f9.ps,width=5cm,angle=270,clip=}\\ \vspace*{0.35cm} \epsfig{figure=h4147f10.ps,width=5cm,angle=270,clip=} \end{figure}$ Figure 7: Spectra of sources No. 8 (top) and 56 (bottom) together with a best-fitting single-temperature thermal plasma model (see Table B.3).
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f11.ps,width=5cm,angle=270,clip=}\\ \vspace*{0.35cm} \epsfig{figure=h4147f12.ps,width=5cm,angle=270,clip=} \end{figure}$ Figure 8: Spectra of sources No. 73 (top) and 86 (bottom) together with a best-fitting absorbed power law model (see Table B.4).
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f13.ps,width=6cm,angle=270,clip=} \end{figure}$ Figure 9: Lightcurves of source No. 33 in the total, soft and hard bands, normalized to the mean count rates, folded on a period of 174.9 s.
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f14.ps,width=6.0cm,angle=270,clip=} \end{figure}$ Figure 10: Lightcurve of source No. 113, normalized to the mean count rate, folded on a period of 201.5 s.
Open with DEXTER

In the text

$\begin{figure} \par\psfig{figure=h4147f15.ps,width=6.0cm,angle=270,clip=} \end{figure}$ Figure 11: Red histogram: cumulative luminosity distribution of the discrete sources in the inner region ( $d < 60\hbox {$^{\prime \prime }$ }$ from the galactic center), together with a powerlaw approximation (index -0.7). Green histogram: cumulative luminosity distribution of the sources in the outer disk, together with a broken powerlaw approximation (break at an emitted luminosity of $8 \times 10^{37}$ erg s^-1 for the assumed spectral model; indices of -1.6 and -0.6 above and below the break). (This figure is available in color in electronic form.)
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f16.ps,width=6.0cm,angle=270,clip=}\\ \vspace{0.1cm} \epsfig{figure=h4147f17.ps,width=6.0cm,angle=270,clip=} \end{figure}$ Figure 12: Top panel: Color-color diagram of the 22 sources in M 83 (the source associated with the background radio galaxy is not included) for which individual spectral fitting is available. Sources with a featureless, hard powerlaw spectrum are plotted as blue diamonds. Sources with emission lines on top of a hard powerlaw spectrum are plotted as cyan triangles. Magenta squares are sources with a featureless soft spectrum. Green triangles are sources characterised by soft, optically-thin thermal plasma emission. Red circles are supersoft sources (blackbody-like emission at temperatures <80 eV). The black star is the galactic nucleus. The numbers refer to the source catalogue in Table A.1. Bottom panel: the colors of those same 22 sources (plotted here with their error bars) are compared with those expected from some simple spectral models: blackbody, disk-blackbody, powerlaw, and optically-thin thermal plasma. The column density increases along each model curve from bottom left to top right, from $n_{\rm H} = 4 \times 10^{20}$ cm^-2 (line-of-sight foreground absorption for M 83) to $n_{\rm H} = 7.5 \times 10^{21}$ cm^-2 for the blackbody and optically-thin thermal plasma models, and to $n_{\rm H} = 2 \times 10^{22}$ cm^-2 for the powerlaw and disk-blackbody models. (This figure is available in color in electronic form.)
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f18.eps,width=8.0cm}\\ \vspace{0.1cm} \epsfig{figure=h4147f19.eps, width=8.0cm} \end{figure}$ Figure 13: Color-color diagrams for the alternative color indices. The symbols and colors of the 22 sources, and the superimposed spectral models are the same as in Fig. 12. For each spectral model, the absorbing column density increases from the bottom to the top of the representative curves.
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f20.eps, width=8.0cm}\\ \vspace{0.1cm} \epsfig{figure=h4147f21.eps, width=8.0cm} \end{figure}$ Figure 14: Top panel: color-color diagram for sources brighter than $\approx$ 10³⁷ erg s^-1, with respective error bars. Bottom panel: color-color diagram for the all sources in the S3 chip, without error bars. In addition to the models shown in Fig. 12, we have also overplotted a two-temperature thermal plasma model ( $kT_{\rm rs,1} = 0.3$ keV, $kT_{\rm rs,2} = 5.0$ keV), normalised so that the high-temperature component accounts for 25% of the emitted flux.
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f22.ps,width=6.0cm,angle=270,clip=}\\ \vspace{0.1cm} \epsfig{figure=h4147f23.ps, width=6.0cm,angle=270} \end{figure}$ Figure 15: Same as Fig. 14 for the alternative color indices. The three groups (A, B, C) are separated by the horizontal dotted lines. (This figure is available in color in electronic form.)
Open with DEXTER

In the text

$\begin{figure} \par\psfig{figure=h4147f24.ps,width=6.0cm,angle=270,clip=} \end{figure}$ Figure 16: Cumulative luminosity distributions of the three groups of sources (normalized to their total numbers) identified in Sect. 5.3. The distributions for groups A, B and C are plotted in red, green and blue respectively. (This figure is available in color in electronic form.)
Open with DEXTER

In the text

$\begin{figure} \par\psfig{figure=h4147f25.eps,width=7.2cm,clip=} \end{figure}$ Figure 17: Location of the discrete X-ray sources classified according to their color group (red for group A sources; green for group B; blue for group C), overplotted onto a continuum-subtracted H $\alpha$ image of M 83. North is up, East is left. The H $\alpha$ image was taken by Stuart Ryder from the Anglo-Australian Telescope.
Open with DEXTER

In the text

$\begin{figure} \par\psfig{figure=h4147f26.eps,width=8.0cm} \end{figure}$ Figure 18: X-ray source count rate versus the H $\alpha$ surface brightness in the region around the source (average value in a circle of radius $5\hbox {$^{\prime \prime }$ }$ ). Here red $\rm circles = group~A$ , green $\rm squares = group~B$ , blue $\rm triangles = group~C$ sources. The lack of detected sources near the bottom right corner of the diagram is due to the completeness limit of our X-ray sample in regions of high H $\alpha$ emission: those regions are also characterized by strong, diffuse X-ray emission, so that faint X-ray sources cannot be detected.
Open with DEXTER

In the text

$\begin{figure} \par\psfig{figure=h4147f27.eps,width=8.8cm} \end{figure}$ Figure 19: Cumulative distributions of the H $\alpha$ surface brightness associated to each group of X-ray sources.
Open with DEXTER

In the text

$\begin{figure} \par\psfig{figure=h4147f28.ps,width=8cm,clip=} \end{figure}$ Figure 20: Group A, B and C sources (green, red and blue circles respectively) overplotted on a map of the radio continuum emission at 6.3 cm. The radio map is a combination of data from the VLA and Effelsberg radio telescopes, at a resolution of 12 $^{\prime \prime }$ , and was produced by S. Sukumar, R. Allen, R. Beck & N. Neininger. (This figure is available in color in electronic form.)
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f29.ps, width=7.2cm,angle=270,clip=}\\ \... ...e{0.35cm} \epsfig{figure=h4147f30.ps, width=7.2cm,angle=270,clip=} \end{figure}$ Figure 21: Color-color plots for X-ray sources in M 83 and M 81, for conventional and alternative color indices (as defined in Sect. 5.2). Here the soft band is defined as 0.2-1.0 keV. Filled red circles represent M 83 sources, and open green circles represent M 81 sources. Error bars have been omitted. (This figure is available in color in electronic form.)
Open with DEXTER

In the text

$\begin{figure} \par\epsfig{figure=h4147f31.ps, width=6.3cm,angle=270,clip=}\\ \... ...e{0.35cm} \epsfig{figure=h4147f32.ps, width=6.3cm,angle=270,clip=} \end{figure}$ Figure 22: The cumulative color distribution of the sources in M 83 (solid line) and M 81 (dashed line). S is defined here as the 0.2-1.0 keV band.
Open with DEXTER

In the text

$\begin{figure} \begin{tabular}{lr} \psfig{figure=h4147f33.ps,width=5.6cm, angle=... ...0} & \psfig{figure=h4147f40.ps,width=5.6cm, angle=270}\end{tabular} \end{figure}$ Figure B.1: Spectra of bright sources of group C: from top left: No. 5 and 31; No. 33 (a candidate X-ray pulsar, lightcurve shown in Fig. 9) and 39 (a background radio galaxy); No. 44 and 60; No. 64 and 72. Their fitting parameters are listed in Table B.4.

In the text

$\begin{figure} \begin{tabular}{lr} \psfig{figure=h4147f41.ps,width=5.6cm, angle=... ... \psfig{figure=h4147f46.ps,width=5.6cm, angle=270}\\ \end{tabular} \end{figure}$ Figure B.2: Spectra of bright sources of group C (continued): from top left: No. 78 and 85; No. 88 and 104. No. 113 (a candidate X-ray pulsar, lightcurve shown in Fig. 10) and No. 121. Their fitting parameters are listed in Table B.4.

In the text

$\begin{figure} \par\epsfig{figure=h4147f1.ps,width=14.0cm,clip=} \end{figure}$	Figure 1: Adaptively-smoothed greyscale Chandra ACIS image of M 83, in the 0.3-8.0 keV band (square-root scale, arbitrary zeropoint). The D₂₅ ellipse and the S3 chip boundaries are overplotted. The region inside the central square is shown in greater detail in Fig. 2.
Open with DEXTER

$\begin{figure} \par\epsfig{figure=fig2eps.eps,width=7cm,clip=} \end{figure}$	Figure 2: Close-up view of the starburst nucleus. The source numbers refer to Table A.1. North is up, and East is left. (This figure is available in color in electronic form.)
Open with DEXTER

$\begin{figure} \par\epsfig{figure=h4147f5.ps,width=5cm,angle=270,clip=}\\ \vspace*{0.35cm} \epsfig{figure=h4147f6.ps,width=5cm,angle=270,clip=} \end{figure}$	Figure 5: The spectra of the two brightest supersoft sources (top: No. 68; bottom: No. 96); see Table B.2 for the fit parameters.
Open with DEXTER

$\begin{figure} \par\epsfig{figure=h4147f7.ps,width=5cm,angle=270,clip=}\\ \vspace*{0.35cm} \epsfig{figure=h4147f8.ps,width=5cm,angle=270,clip=} \end{figure}$	Figure 6: Spectra of sources No. 3 (top) and 27 (bottom) together with a best-fitting absorbed power law model with emission lines (see Table B.3).
Open with DEXTER

$\begin{figure} \par\epsfig{figure=h4147f9.ps,width=5cm,angle=270,clip=}\\ \vspace*{0.35cm} \epsfig{figure=h4147f10.ps,width=5cm,angle=270,clip=} \end{figure}$	Figure 7: Spectra of sources No. 8 (top) and 56 (bottom) together with a best-fitting single-temperature thermal plasma model (see Table B.3).
Open with DEXTER

$\begin{figure} \par\epsfig{figure=h4147f11.ps,width=5cm,angle=270,clip=}\\ \vspace*{0.35cm} \epsfig{figure=h4147f12.ps,width=5cm,angle=270,clip=} \end{figure}$	Figure 8: Spectra of sources No. 73 (top) and 86 (bottom) together with a best-fitting absorbed power law model (see Table B.4).
Open with DEXTER

$\begin{figure} \par\epsfig{figure=h4147f13.ps,width=6cm,angle=270,clip=} \end{figure}$	Figure 9: Lightcurves of source No. 33 in the total, soft and hard bands, normalized to the mean count rates, folded on a period of 174.9 s.
Open with DEXTER

$\begin{figure} \par\epsfig{figure=h4147f14.ps,width=6.0cm,angle=270,clip=} \end{figure}$	Figure 10: Lightcurve of source No. 113, normalized to the mean count rate, folded on a period of 201.5 s.
Open with DEXTER

$\begin{figure} \par\epsfig{figure=h4147f18.eps,width=8.0cm}\\ \vspace{0.1cm} \epsfig{figure=h4147f19.eps, width=8.0cm} \end{figure}$	Figure 13: Color-color diagrams for the alternative color indices. The symbols and colors of the 22 sources, and the superimposed spectral models are the same as in Fig. 12. For each spectral model, the absorbing column density increases from the bottom to the top of the representative curves.
Open with DEXTER

$\begin{figure} \par\epsfig{figure=h4147f22.ps,width=6.0cm,angle=270,clip=}\\ \vspace{0.1cm} \epsfig{figure=h4147f23.ps, width=6.0cm,angle=270} \end{figure}$	Figure 15: Same as Fig. 14 for the alternative color indices. The three groups (A, B, C) are separated by the horizontal dotted lines. (This figure is available in color in electronic form.)
Open with DEXTER

$\begin{figure} \par\psfig{figure=h4147f24.ps,width=6.0cm,angle=270,clip=} \end{figure}$	Figure 16: Cumulative luminosity distributions of the three groups of sources (normalized to their total numbers) identified in Sect. 5.3. The distributions for groups A, B and C are plotted in red, green and blue respectively. (This figure is available in color in electronic form.)
Open with DEXTER

$\begin{figure} \par\psfig{figure=h4147f25.eps,width=7.2cm,clip=} \end{figure}$	Figure 17: Location of the discrete X-ray sources classified according to their color group (red for group A sources; green for group B; blue for group C), overplotted onto a continuum-subtracted H $\alpha$ image of M 83. North is up, East is left. The H $\alpha$ image was taken by Stuart Ryder from the Anglo-Australian Telescope.
Open with DEXTER

$\begin{figure} \par\psfig{figure=h4147f27.eps,width=8.8cm} \end{figure}$	Figure 19: Cumulative distributions of the H $\alpha$ surface brightness associated to each group of X-ray sources.
Open with DEXTER

$\begin{figure} \par\psfig{figure=h4147f28.ps,width=8cm,clip=} \end{figure}$	Figure 20: Group A, B and C sources (green, red and blue circles respectively) overplotted on a map of the radio continuum emission at 6.3 cm. The radio map is a combination of data from the VLA and Effelsberg radio telescopes, at a resolution of 12 $^{\prime \prime }$ , and was produced by S. Sukumar, R. Allen, R. Beck & N. Neininger. (This figure is available in color in electronic form.)
Open with DEXTER

$\begin{figure} \par\epsfig{figure=h4147f29.ps, width=7.2cm,angle=270,clip=}\\ \... ...e{0.35cm} \epsfig{figure=h4147f30.ps, width=7.2cm,angle=270,clip=} \end{figure}$	Figure 21: Color-color plots for X-ray sources in M 83 and M 81, for conventional and alternative color indices (as defined in Sect. 5.2). Here the soft band is defined as 0.2-1.0 keV. Filled red circles represent M 83 sources, and open green circles represent M 81 sources. Error bars have been omitted. (This figure is available in color in electronic form.)
Open with DEXTER

$\begin{figure} \par\epsfig{figure=h4147f31.ps, width=6.3cm,angle=270,clip=}\\ \... ...e{0.35cm} \epsfig{figure=h4147f32.ps, width=6.3cm,angle=270,clip=} \end{figure}$	Figure 22: The cumulative color distribution of the sources in M 83 (solid line) and M 81 (dashed line). S is defined here as the 0.2-1.0 keV band.
Open with DEXTER