Dark matter annihilation and decay in dwarf spheroidal galaxies: the classical and ultrafaint dSphs

By V. Bonnivard, C. Combet, M. Daniel, S. Funk, A. Geringer-Sameth, J. Hinton, D. Maurin, Justin I. Read, Subir Sarkar, S. Sarkar and 2 more. 2015

180 citations recorded by the source corpus.

Dwarf spheroidal (dSph) galaxies are prime targets for present and future gamma-ray telescopes hunting for indirect signals of particle dark matter. The interpretation of the data requires careful assessment of their dark matter content in order to derive robust constraints on candidate relic particles. Here, we use an optimised spherical Jeans analysis to reconstruct the `astrophysical factor' for both annihilating and decaying dark matter in 21 known dSphs. Improvements with respect to previous works are: (i) the use of more flexible luminosity and anisotropy profiles to minimise biases, (ii) the use of weak priors tailored on extensive sets of contamination-free mock data to improve the confidence intervals, (iii) systematic cross-checks of binned and unbinned analyses on mock and real data, and (iv) the use of mock data including stellar contamination to test the impact on reconstructed signals. Our analysis provides updated values for the dark matter content of 8 `classical' and 13 `ultrafaint' dSphs, with the quoted uncertainties directly linked to the sample size; the more flexible parametrisation we use results in changes compared to previous calculations. This translates into our ranking of potentially-brightest and most robust targets---viz., Ursa Minor, Draco, Sculptor---, and of the more promising, but uncertain targets---viz., Ursa Major 2, Coma---for annihilating dark matter. Our analysis of Segue 1 is extremely sensitive to whether we include or exclude a few marginal member stars, making this target one of the most uncertain. Our analysis illustrates challenges that will need to be addressed when inferring the dark matter content of new `ultrafaint' satellites that are beginning to be discovered in southern sky surveys.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/dab9f84f41b3784ea34b4664f5ff089b3ee7e491

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Citations in the corpus

DarkSUSY 6: an advanced tool to compute dark matter properties numerically (2018, background): “Observationally, however, the distribution of DM on scales relevant for DM searches is often only poorly constrained (with the exception of classical dwarf spheroidal galaxies – though even here uncertainties in halo properties relevant for DM searches may be somewhat larger [68] than what is typica”
The hidden giant: discovery of an enormous Galactic dwarf satellite in Gaia DR2 (2018, background): “This is about 3 orders of magnitude below the J values of the ‘top tier’ Milky Way dwarfs where we expect the strongest annihilation signals (e.g. Bonnivard et al. 2015).”
Limits to dark matter annihilation cross-section from a combined analysis of MAGIC and Fermi-LAT observations of dwarf satellite galaxies (2016, methodology): “[44], using a more flexible parameterization for the stellar velocity distributions and more stringent criteria for stellar membership, produces substantially larger J-factor uncertainties for the ultra-”
SEARCHING FOR DARK MATTER ANNIHILATION IN RECENTLY DISCOVERED MILKY WAY SATELLITES WITH FERMI-LAT (2016, methodology): “In Figure 5, we show that a simple scaling relationship between J-factor and distance can be clearly seen in the J-factors derived by several groups (i.e., Geringer-Sameth et al. 2015a; Martinez 2015; Bonnivard et al. 2015a).”
Dark matter cores all the way down (2015, background): “E-mail: justin.inglis.read@gmail.com for dark matter annihilation or decay (e.g. Lake 1990; Charbonnier et al. 2011; Malyshev et al. 2014; Bonnivard et al. 2015; Drlica-Wagner et al. 2015; Geringer-Sameth et al. 2015).”