Revisiting Clusters of PBHs as Dark Matter Candidates

In this paper we revisit Primordial Black Hole (PBH) clusters as Dark Matter (DM) candidates. Here, we present a continuation of our previous work, extending the analysis. The analysis is devoted to re-consideration of the constraint on PBH abundance from stellar cluster observation in dwarf galaxy Eridanus II. We take into account the non-trivial density profile of PBH clusters in order to re-estimate the energy exchange between PBHs and stars. Here we keep momentum approximation to strengthen the constraint, making it robust. The impact of the density profile concludes in the form of the Coulomb logarithm, making analysis trivial, but showing important results. It is shown that density profile matters and energy exchange can be suppressed by up to three times due to it, making clusters of PBHs more viable DM candidates compared to single PBHs, if their radius is sufficiently large.