Astronomy & Astrophysics

All Figures

$\begin{figure} \par\includegraphics[width=13.5cm]{4720fig1.eps} \end{figure}$ Figure 1: The XMM-Newton view of the field of 1E 1207.4-5209. Data from the MOS1 and MOS2 camera have been merged to produce the image. The exposure time is of $\sim$ 200 ks per camera. The target is the bright source close to the center of the field. Many ( $\sim$ 200) serendipitous sources and the bright emission from parts of the shell of the host supernova remnant G296.5+10.0 are clearly visible. The colors are energy-coded, red represents photons in the 0.3-0.6 keV band, green and blue correspond to the 0.6-1.5 keV and 1.5-8 keV bands respectively.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.2cm,clip]{4720fig2.ps} \end{figure}$ Figure 2: Period history of 1E 1207.4-5209. Circles are the Chandra measurements, crosses XMM-Newton.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{4720fig3.ps} \end{figure}$ Figure 3: Folded light curve of 1E 1207.4-5209 in four energy ranges.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{4720fig4.ps} \end{figure}$ Figure 4: Ratio of the data to the continuum best fit models for 1E 1207.4-5209 (black points) and for the bright quasar 3C 273 (grey points). The EPIC/pn observation of 3C 273 (performed on 2001/06/13; pn operated in Small Window mode with the Medium filter) yielded $\sim$ 62 ks of good exposure time. PATTERN 0-4 events were extracted from a 43'' radius region centered on the source position. Ad-hoc response files were generated. The best fit ( $\chi ^2_\nu =1.29$ , 1099 d.o.f.) spectral model in the range 0.3-6 keV is a slightly absorbed ( $N_{\rm H} \sim 1.2 \times 10^{20}$ cm^-2) double power law (photon indices $\alpha_{\rm ph~1}\sim2.79$ and $\alpha_{\rm ph~2}\sim1.43$ ; 0.3-6 keV fluxes $F_1\sim 4.47 \times 10^{-11}$ erg cm^-2 s^-1 and $F_2\sim 8.67 \times 10^{-11}$ erg cm^-2 s^-1). Deviations at the $\sim$ 6-7% level are seen in the case of the featureless 3C 273 spectrum owing to residual miscalibrations at the Si (1.839 keV) and Au (2.209 keV) edges. These artefacts can be reproduced ( $\chi ^2_\nu =1.05$ , 1093 d.o.f.) by two Gaussian lines in absorption centered at the edge energies, with equivalent width of $\sim$ 5.5 eV and $\sim$ 7.7 eV for the Si and the Au edge case, respectively. The $\sim$ 2.1 keV feature seen in the spectrum of 1E 1207.4-5209 (see text and Table 2) is markedly stronger, with a >13 times higher equivalent width, and is totally unrelated to the calibration leftovers which are never seen in dim sources.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{4720fig5.ps} \end{figure}$ Figure 5: Fit of the phase-integrated data. The model (double blackbody plus line components) is described in the text. From top to bottom, the panels show data from the pn, the MOS1 and the MOS2 cameras. In each panel the data are compared to the model folded through the instrumental response (upper plot); the lower plot shows the residuals in units of sigma.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{4720fig6.ps} \end{figure}$ Figure 6: Residuals in units of sigma obtained by comparing the data with the best fit thermal continuum model. The presence of four absorption features at $\sim$ 0.7 keV, $\sim$ 1.4 keV, $\sim$ 2.1 keV and $\sim$ 2.8 keV in the pn spectrum is evident. The three main features are also independently detected by the MOS1 and MOS2 cameras.
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In the text

$\begin{figure} \par\includegraphics[height=13cm,width=14.5cm,angle=-90,clip]{4720fig7.ps} \end{figure}$ Figure 7: Folded light curves of 1E 1207.4-5209. The energy ranges have been selected in order to put in evidence the impact of the phase variation of the features on the source pulsation. The three panels to the left show that in the spectral regions less affected by the main features the pulsed fraction is of order $\sim$ 4-6%. The three panels to the right show that the pulsation is much higher ( $\sim$ 10%) in the energy ranges where the three main features are seen.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{4720fig8.ps} \end{figure}$ Figure 8: Residuals in units of sigma obtained by comparing the data with the best fit continuum model (line components removed) for the phase-resolved spectra. The variations in width, depth and shape of the absorption features as a function of the pulse phase are evident. Structured residuals are observed in the range 0.4-0.7 keV for the "rise'' spectrum and (more significantly) in the range 0.9-1.2 keV in the "decline'', where broad emission features could be present. We did not attempt to model these structures, which are likely artefacts due to an inadequate description of the main absorption features' profile.
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In the text

$\begin{figure} \par\includegraphics[width=13.5cm,clip]{4720fig9.ps} \end{figure}$ Figure 9: Combined V-band FORS1 image of the central region of the 1E 1207-5209 field. The circles indicate the expected source positions computed from the Chandra/ACIS (0.6'' radius), MOS1 and MOS2 (2'' radius) data. The good agreement among the three independent positions gives us confidence on the overall correctness of our analysis. No sources down to $R \sim 27.1$ and $V\sim 27.3$ are seen inside the error circles. The object labelled with the two small ticks, visible also in the NTT observation of Bignami et al. (1992), falls just outside of the MOS1 error circle. Its time-integrated magnitude in the combined images is $V \sim 25.8$ and $R \sim 24.5$ , with uncertainties of $\sim$ 0.1 mag. Its profile is consistent with a stellar-like object. Its flux varied of $\sim$ 0.4 mag in the V-band images (from $V \sim 26.2$ to $V \sim 25.7$ ), collected during 3 nights, and of $\sim$ 1.5 mag in the R-band images, collected during 4 nights. It is most probably a background AGN.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.2cm,clip]{4720fig2.ps} \end{figure}$	Figure 2: Period history of 1E 1207.4-5209. Circles are the Chandra measurements, crosses XMM-Newton.
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$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{4720fig3.ps} \end{figure}$	Figure 3: Folded light curve of 1E 1207.4-5209 in four energy ranges.
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{4720fig5.ps} \end{figure}$	Figure 5: Fit of the phase-integrated data. The model (double blackbody plus line components) is described in the text. From top to bottom, the panels show data from the pn, the MOS1 and the MOS2 cameras. In each panel the data are compared to the model folded through the instrumental response (upper plot); the lower plot shows the residuals in units of sigma.
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$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{4720fig6.ps} \end{figure}$	Figure 6: Residuals in units of sigma obtained by comparing the data with the best fit thermal continuum model. The presence of four absorption features at $\sim$ 0.7 keV, $\sim$ 1.4 keV, $\sim$ 2.1 keV and $\sim$ 2.8 keV in the pn spectrum is evident. The three main features are also independently detected by the MOS1 and MOS2 cameras.
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