3 2009 Fermi Symposium, Washington, D.C., Nov. 2-5 We further assume that these substructures are well represented by a spherically symmetric NFW density profile Navarro et al. [1997]. Under this assumption the gamma-ray luminosity from a given substructure can be written as a scaling law Springel et al. [2008]: during the hadronization of the primary annihilation products; (ii) monoenergetic gamma-ray lines for neu- tralino annihilation in two-body final states contain- ing photons; (iii) internal bremsstrahlung (IB), which leads to the emission of an additional photon in the final state; the IB contribution to the spectrum is typ- ically dominant at high energies resulting in a charac- teristic bump. Processes (ii) and (iii) are subdominant to process (i), but they display distinctive spectral fea- tures intrinsic to the phenomenon of annihilation. In Fig. 1, we have shown only 4 of all the benchmark points we have considered; the rest have very similar features and lie in between these 4 cases. Fig. 1 also indicates that the normalization of the spectrum of f$_{SUSY}$ typically varies by three orders of magnitude among the different regions of the allowed parameter space. where V$_{max}$ is the maximum rotational velocity of the subhalo and r$_{max}$ is the radius where this maximum is reached. The most recent high-resolution N-body sim- ulations support a slightly revised density profile that becomes gradually shallower towards the center, the so called Einasto profile. For this case, the coefficient 1 . 23 in Eq. (4) changes to 1.87, increasing our results effectively by 50%. This is an insignificant difference compared to other uncertainties in the analysis of the dark matter annihilation radiation. For the purposes of our work, the NFW profile is a good approxima- tion and using it simplifies comparisons to a number of results in the literature. Our map-making method then becomes a task to accurately accumulate the properly redshifted emis- sion from these structures in discretized representa- tions of the sky and to include a resolution correc- tion for poorly resolved objects. All our maps use N$_{pix}$ = 12 × 512 2 ∼ π × 10 6 pixels, corresponding to an angular resolution of ∼ 0 . 115 $^{◦}$. For the rest of our analysis, we will use one par- ticular benchmark point, which is the one we high- light with a thick blue line in Fig. 1. It is a model with m$_{χ}$ = 185 GeV that gives an upper limit on f$_{SUSY}$ for the benchmark points in the bulk region and is also close to the maximum value of f$_{SUSY}$ for all the benchmark points analyzed. The latter is the main reason to choose this particular model because it is desirable that the predicted gamma-ray flux has a large value among the different theoretical possi- bilities. There are other reasons as well. The mass of the neutralino in this model is “safely” larger than the lower mass bounds coming from experimental con- straints ( m$_{χ}$ > 50 GeV according to Heister et al. [2004]), but low enough to be detectable in the ex- periments available in the near future. Also, a high value of the parameter tan β seems to be favored by other theoretical expectations N´ u˜ nez et al. [2008]. A given pixel in the simulated maps covers a solid angle ΔΩ$_{pix}$. Our map-making code computes the average value of the specific intensity within the area subtended by this solid angle by conservatively dis- tributing the emission of each substructure over the appropriate pixels. Combining Eqs. (2 − 4) we can write the relevant sum over all substructures in the light-cone as: The specific intensity (Eq. 1) describes the total emission from dark matter annihilations integrated over the full backwards light cone along a certain di- rection. We use the data of the MS-II to fill the whole volume contained in the past-light cone of an observer located at a fiducial position at z = 0. Since there are only 68 simulation outputs in total, we can approx- imate the temporal evolution of structure growth by using at each redshift along the past light-cone the output time closest to this epoch. To cover all space, we use periodic replication of the simulation box. Our strategy is not to account for the emission at the level of individual dark matter particles, but in- stead to use entire halos and subhalos, allowing us to accurately correct for resolution effects. The list of dark matter particles at each output time is hence replaced by a catalog of dark matter substructures. where the function w ( d$_{h}$, r$_{h}$ ) is a weight function that distributes the luminosity of a given halo onto the pix- els overlapping with the projected “size”of the halo; the latter depends on the distance of the observer to the halo d$_{h}$ and the transverse distance r$_{h}$ between the halo center and the center of the pixels it touches. Except for structures that are very nearby, the high central concentration of the emission of a subhalo and the limited angular resolution of our maps give most subhalos the character of unresolved point sources. For the purpose of extending the predictions of our maps down to the damping scale limit of neutrali- nos ( ∼ 10 − $^{6}$M ⊙ ), we divide the maps into separate components: (i) the contribution of resolved halos and subhalos with a minimum mass of 6 . 89 × 10 8 h − $^{1}$M ⊙ (called “ReHS” in the following); (ii) the contribu- tion of unresolved main halos with masses in the range I$_{γ,}$$_{0}$ (ΔΩ$_{pix}$) = 1 8 π ∑ hϵ ΔΩ$_{pix}$ L$_{h}$w ( d$_{h}$, r$_{h}$ ) E$_{γ,}$$_{0}$f$_{SUSY}$ ( z$_{h}$ ) |$_{E}$$_{γ,}$$_{0}$ , (5) L$_{h}$ = ∫ ρ 2 $_{NFW}$( r ) d V = 1 . 23 V 4 max G $^{2}$r$_{max}$ , (4) 3. The dark matter annihilation contribution to the EGB eConf C091122