2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/183545We estimate the gamma ray fluxes from the residual annihilations of Dark Matter particles having a mass mdm \in [MeV, O(GeV)] and compare them to observations. We find that particles lighter than O(100 MeV) are excluded unless their cross section is S-wave suppressed.4 pages. No figure. Values corrected (last column Table.1). Text clarified. Conclusions unchangedAstrophysicstext