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$\begin{figure} \par\includegraphics[width=6.1cm,clip]{6982f1a.eps}\hspace*{6mm} \includegraphics[width=6.1cm,clip]{6982f1b.eps}\end{figure}$ Figure 1: Raw data spectra around the energies of two ⁶⁰Fe lines in one-INTEGRAL-orbit observations (3 days), representing the instrumental lines and continuum background. For the 1173 keV case ( left), three strong instrumental lines are obvious: ⁴⁴Sc (1157 keV), ⁶⁰Co (1172.9 keV), ¹⁸²Ta (189.4 keV), and the ⁶⁰Co line blends with the ⁶⁰Fe line (Weidenspointner et al. 2003). For the 1333 keV case ( right), the ⁶⁰Co background line (1332.5 keV) and the other strong instrumental line of ⁶⁹Ge (1336.8 keV) blend with the ⁶⁰Fe line, an instrumental line at 1347 keV also comes from ⁶⁹Ge electron captures.
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In the text

$\begin{figure} \par\includegraphics[width=5.65cm,clip]{6982f2a.eps}\hspace*{6mm} \includegraphics[width=5.65cm,clip]{6982f2b.eps}\end{figure}$ Figure 2: Background coefficients for the ⁶⁰Co radioactivity build-up model around the 1173 keV ( left) and 1333 keV ( right) lines, respectively.
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In the text

$\begin{figure} \par\includegraphics[width=7.6cm,clip]{6982f3a.ps}\hspace*{3mm} \includegraphics[width=7.8cm,clip]{6982f3b.ps}\end{figure}$ Figure 3: Two plausible sky distribution models adopted for diffuse ⁶⁰Fe emission from the Galaxy. Both have been derived from COMPTEL ²⁶Al measurements (Plüschke et al. 2001; Knödlseder et al. 1999). The image obtained with the Maximum-entropy method ( left) shows more structure, while the image derived with the Multi-resolution Expectation Maximization Method (MREM) appears smooth from its noise-filtering, accepting only image structure which is enforced by the measurements.
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In the text

$\begin{figure} \par {\hspace*{2cm}\includegraphics[width=10.1cm,clip]{6982f4a.ep... ....eps}\hspace*{1.1cm} \includegraphics[width=6.6cm,clip]{6982f4c.eps}\end{figure}$ Figure 4: Residuals of counts after fitting, in different projections. The upper figure shows the residuals versus time (days of the Julian Date, starts at 1 Jan. 2000), where counts per pointing have been re-binned into 3-day intervals for clarity (here for single events SE in the 1163-1182 keV energy band). The lower two figures present the residuals projected with the energy (SE cases for the bands around the 1173 and 1333 keV lines separately). Two different time periods are shown (dashed: first half of database; solid: second half of database). For the 1333 keV line case, because of the strong instrumental ⁶⁹Ge line at 1337 keV, there still exist the large residuals around 1337 keV. Residuals around zero generally confirm that our background models are adequate except for the instrumental line around 1337 keV, with $\chi ^2/{\rm d.o.f.}$ in model fittings (Sect. 3.3): 1.182 (SE) and 0.670 (ME) for the 1173 keV line; 1.191 (SE) and 0.667 (ME) for the 1333 keV line.
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In the text

$\begin{figure} \par\includegraphics[width=14.7cm,clip]{6982f5.eps}\end{figure}$ Figure 5: The spectra of two gamma-ray lines of ⁶⁰Fe from the inner Galaxy: 1173 keV and 1333 keV. We have shown the results both from SE and ME databases. The data points are fitted with Gaussian profiles of fixed instrumental width (2.76 keV), and fixed continuum slope (flat), with $\chi ^2/{\rm d.o.f.}$ of fits: 1.06 (SE) and 1.09 (ME) for the 1173 keV line and 1.16 (SE) and 1.11 (ME) for the 1333 keV line. For the SE database, we find a line flux of (4.2 $\pm$ 1.6) $\times$ $10^{-5}~{\rm ph~cm^{-2}~s^{-1}~rad^{-1}}$ for the 1173 keV line and (3.5 $\pm$ 1.5) $\times$ $10^{-5}~{\rm ph~cm^{-2}~s^{-1}~rad^{-1}}$ for the 1333 keV line. For the ME database, the line flux is (5.8 $\pm$ 1.9) $\times$ $10^{-5}~{\rm ph~cm^{-2}~s^{-1}~rad^{-1}}$ for the 1173 keV line and (5.2 $\pm$ 2.1) $\times$ $10^{-5}~{\rm ph~cm^{-2}~s^{-1}~rad^{-1}}$ for the 1333 keV line (also see Table 1).
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In the text

$\begin{figure} \includegraphics[width=12cm,clip]{6982f6.eps}\end{figure}$ Figure 6: The combined spectrum of the ⁶⁰Fe signal in the inner Galaxy, superimposing the four spectra of Fig. 2. In the laboratory, the line energies are 1173.23 and 1332.49 keV; here superimposed bins are zero at 1173 and 1333 keV. We find a detection significance of 4.9 $\sigma$ . The solid line represents a fitted Gaussian profile of fixed instrumental width (2.76 keV), and a flat continuum. The average line flux is estimated as (4.4 $\pm$ 0.9) $\times$ $10^{-5}~{\rm ph~cm^{-2}~s^{-1}~rad^{-1}}$ .
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In the text

$\begin{figure} \par\includegraphics[width=12cm,clip]{6982f7.eps}\end{figure}$ Figure 7: Flux ratio of the gamma-ray lines from the two long-lived radioactive isotopes ⁶⁰Fe/²⁶Al from several observations, including our SPI result (also see Table 2), with upper limits shown at 2 $\sigma$ for all reported values, and comparison with the recent theoretical estimates (the upper hatched region from Prantzos 2004; the horizontal line taken from Timmes et al. 1995; the lower hatched region, see Limongi & Chieffi 2006). Our present work finds the line flux ratio to be (14.8 $\pm$ 6.0) $\%$ . Note that the primary instrument results on ⁶⁰Fe is compromised in the figure by different and uncertain ²⁶Al fluxes used for the ⁶⁰Fe/²⁶Al ratio (see Table 2 for details).
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In the text

$\begin{figure} \par\includegraphics[width=5.65cm,clip]{6982f2a.eps}\hspace*{6mm} \includegraphics[width=5.65cm,clip]{6982f2b.eps}\end{figure}$	Figure 2: Background coefficients for the ⁶⁰Co radioactivity build-up model around the 1173 keV ( left) and 1333 keV ( right) lines, respectively.
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