All Figures

$\begin{figure} \par\includegraphics[width=15cm,height=11cm,clip]{9691fig1.eps}\end{figure}$ Figure 1: The Cosmic Infrared Background (CIRB) spectrum as measured by independent groups in the all-sky COBE maps (e.g. Hauser et al. 1998), and the estimates of the optical extragalactic background based on ultradeep integrations by the HST in the HDF (Madau & Pozzetti 2000). The three lower datapoints in the far-IR are from a re-analysis of the DIRBE data by Lagache et al. (1999), the shaded areas from Fixsen et al. (1998) and Lagache et al. The two lower limits at 70 and 160 $\mu$ m (green filled circles) come from a stacking analysis of Spitzer data by Dole et al. (2006). The two mid-IR datapoints at 15 and 24 $\mu$ m are the resolved fraction of the CIRB by the deep ISO surveys IGTES (Elbaz et al. 2002) and Papovich et al. (2004). The four triangle datapoints are from the integration of the IRAC galaxy counts by Fazio et al. (2004), except the one at 8 $\mu$ m which comes from our own analysis (see text). The dotted histograms are limits set by TeV cosmic opacity measurements (Stanev & Franceschini 1998). The thick line is the predicted CIRB spectrum from the multi-wavelength reference model for galaxy evolution discussed in the present paper. The lower dashed line is the expected intensity based on the assumption that the local IR emissivity of galaxies observed by IRAS does not evolve with cosmic time: the distance of the two curves, much larger in the far-IR than it is in the optical/near-IR, illustrates the different evolutionary effects in the two waveband intervals and due to the completely different photon-generating processes. The dashed line corresponds to the inclusion of an excess background intensity from unresolved sources (e.g. Population III stars), that we have considered, and still marginally consistent with our analysis of TeV BLAZAR spectra, see Sect. 5.2. The maximal total intensity of this additional background is $I_{\rm bol}\simeq 6$ nW/m²/sr.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,,height=6.3cm,clip]{9691fig2.eps}\end{figure}$ Figure 2: Comparison of the observed galaxy number counts in the B, V, R bands (shown as datapoints) with those predicted by the model in Sect. 3.2 (long dash lines). Datapoints are from Berta et al. (2006).
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In the text

$\begin{figure} \par\includegraphics[width=9cm,height=6.48cm,clip]{9691fig3.eps}\end{figure}$ Figure 3: Evolution of the comoving bolometric luminosity density from 6 to 1000 $\mu$ m for the IR-selected galaxy population, based on the model discussed in Sect. 3.3. The luminosity density is expressed here in solar luminosities per cubic Mpc. Lower continuous red line: quiescent spiral population. Blue continuous line: type-I AGNs. Green short-dashed line: evolving moderate-luminosity starbursts. Red long-dashed line: high-luminosity starbursts. The upper continuous line is the total emissivity.
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In the text

$\begin{figure} \par\includegraphics[width=16.5cm,height=10.8cm,clip]{9691fig4.eps}\end{figure}$ Figure 4: The redshift-dependent photon number density multiplied by the photon energy $\epsilon$ . The number density here is in proper (physical, not comoving) units [cm³] and $\epsilon$ in eV. Various curves are for different redshifts: red correspond to z=0, 0.2, 0.4; green to z=0.6, 0.8, 1.0; blue to z=1.2, 1.4, 1.6; cyan to z=1.8, 2. Photons are generated by our model of the evolution of cosmic sources discribed in Sect. 3.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,height=7.7cm,clip]{9691fig5.eps}\end{figure}$ Figure 5: A comparison of the redshift dependence of the proper photon number density obtained by our galaxy evolutionary models (continuous lines) with that corresponding to the case of a non-evolving population (dashed lines). The lines with black, red, blue and green colors correspond to z=0, 0.6, 1.2, 1.8. Our accounting of the evolution effects makes the predicted background photon density much lower at high-z (z>0.6) than the no-evolution prediction, particularly in the optical.
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In the text

$\begin{figure} \par\includegraphics[width=9cm,height=5.45cm,clip]{9691fig6.eps}\end{figure}$ Figure 6: The energies corresponding to optical depth values of $\tau =0.1$ , 1 and 10 for photon-photon collisions, as a function of the redshiftdistance of the source.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,height=6.4cm,clip]{9691fig7.eps}\end{figure}$ Figure 7: The optical depth by photon-photon collision as a function of the photon energy for sources located at z=0.003, 0.01, 0.03, 0.1, 0.3, 0.5, 1, 1.5, 2, 2.5, 3, 4 from bottom to top.
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In the text

$\begin{figure} \par\mbox{\resizebox{9.cm}{!}{ \includegraphics{9691fig8a.eps}}\resizebox{9.cm}{!}{ \includegraphics{9691fig8b.eps}} } \end{figure}$ Figure 8: Top left: absorption correction estimated for the spectrum of the source PKS 2005-489 (z=0.071) (Aharonian et al. 2005). Bottom left: the observed (open black) and absorption-corrected (filled red) spectrum. Top right: absorption correction for the source 1ES 1101-232 at z=0.186 (Aharonian et al. 2006). Bottom right: the observed (open black) and absorption-corrected (filled red) spectrum. Note the slight energy shift of the corrected spectrum that we applied for clarity.
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In the text

$\begin{figure} \par\mbox{\resizebox{9.cm}{!}{ \includegraphics{9691fig9a.eps}}\resizebox{9.cm}{!}{ \includegraphics{9691fig9b.eps}} } \end{figure}$ Figure 9: Top left: absorption correction for the source MKN 501 at z=0.034 (Aharonian et al. 1999). Bottom left: the observed (open black) and absorption-corrected (filled red) spectrum. Top right: absorption correction for the source MKN 421 at z=0.03 (Aharonian et al. 2002). Bottom right: the observed (open black) and absorption-corrected (filled red) spectrum.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{9691fig10.eps}\end{figure}$ Figure 10: The effect on the spectrum of the source 1ES 1101-232 of the inclusion of a truly diffuse background in addition to that from resolved sources. The excess background is assumed to have the same spectrum as estimated by Matsumoto et al. (2005), but is down-scaled by a factor of 5. The corresponding total spectral intensity at z=0 is resported as a thick dashed line in Fig. 1. Top: spectral correction for $\gamma -\gamma$ opacity. Bottom: the observed (open black) and absorption-corrected (filled red) spectrum, the two best-fit values of $\Gamma _{\rm intrinsic}=1.15$ and 1 refer to the lower and higher energy portions of the spectrum.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,,height=6.3cm,clip]{9691fig2.eps}\end{figure}$	Figure 2: Comparison of the observed galaxy number counts in the B, V, R bands (shown as datapoints) with those predicted by the model in Sect. 3.2 (long dash lines). Datapoints are from Berta et al. (2006).
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$\begin{figure} \par\includegraphics[width=9cm,height=5.45cm,clip]{9691fig6.eps}\end{figure}$	Figure 6: The energies corresponding to optical depth values of $\tau =0.1$ , 1 and 10 for photon-photon collisions, as a function of the redshiftdistance of the source.
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$\begin{figure} \par\includegraphics[width=8.8cm,height=6.4cm,clip]{9691fig7.eps}\end{figure}$	Figure 7: The optical depth by photon-photon collision as a function of the photon energy for sources located at z=0.003, 0.01, 0.03, 0.1, 0.3, 0.5, 1, 1.5, 2, 2.5, 3, 4 from bottom to top.
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$\begin{figure} \par\mbox{\resizebox{9.cm}{!}{ \includegraphics{9691fig9a.eps}}\resizebox{9.cm}{!}{ \includegraphics{9691fig9b.eps}} } \end{figure}$	Figure 9: Top left: absorption correction for the source MKN 501 at z=0.034 (Aharonian et al. 1999). Bottom left: the observed (open black) and absorption-corrected (filled red) spectrum. Top right: absorption correction for the source MKN 421 at z=0.03 (Aharonian et al. 2002). Bottom right: the observed (open black) and absorption-corrected (filled red) spectrum.
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