Search

Abstract Clusters of galaxies are the largest known gravitationally bound structures in the Universe, with masses around 1 0 15 M ⊙ , most of it in the form of dark matter. The ground-based Imaging Atmospheric Cherenkov Telescope MAGIC made a deep survey of the Perseus cluster of galaxies using almost 400 h of data recorded between 2009 and 2017. This is the deepest observational campaign so far on a cluster of galaxies in the very high energy range. We search for gamma-ray signals from dark matter particles in the mass range between 200 GeV and 200 TeV decaying into standard model pairs. We apply an analysis optimized for the spectral and morphological features expected from dark matter decays and find no evidence of decaying dark matter. From this, we conclude that dark matter particles have a decay lifetime longer than ∼ 1 0 26 s in all considered channels. Our results improve previous lower limits found by MAGIC and represent the strongest limits on decaying dark matter particles from ground-based gamma-ray instruments. [ABSTRACT FROM AUTHOR]

We present the first results from very-high-energy observations of the dwarf spheroidal satellite candidate Triangulum II with the MAGIC telescopes from 62.4 h of good-quality data taken between August 2016 and August 2017. We find no gamma-ray excess in the direction of Triangulum II, and upper limits on both the differential and integral gamma-ray flux are presented. Currently, the kinematics of Triangulum II are affected by large uncertainties leading to a bias in the determination of the properties of its dark matter halo. Using a scaling relation between the annihilation J -factor and heliocentric distance of well-known dwarf spheroidal galaxies, we estimate an annihilation J -factor for Triangulum II for WIMP dark matter of log J ann (0. 5 °) ∕ GeV 2 cm − 5 = 19. 35 ± 0. 37. We also derive a dark matter density profile for the object relying on results from resolved simulations of Milky Way sized dark matter halos. We obtain 95% confidence-level limits on the thermally averaged annihilation cross section for WIMP annihilation into various Standard Model channels. The most stringent limits are obtained in the τ − τ + final state, where a cross section for annihilation down to 〈 σ ann v 〉 = 3. 05 × 1 0 − 24 cm3 s−1 is excluded. [ABSTRACT FROM AUTHOR]