Cosmological dark matter annihilations into γ rays: A closer look

By P. Ullio, L. Bergstrom, J. Edsjo, C. Lacey. 2002

240 citations recorded by the source corpus.

We investigate the prospects of detecting weakly interacting massive particle (WIMP) dark matter by measuring the contribution to the extragalactic gamma-ray radiation induced, in any dark matter halo and at all redshifts, by WIMP pair annihilations into high-energy photons. We perform a detailed analysis of the very distinctive spectral features of this signal, recently proposed in a short letter by three of the authors: The gamma-ray flux which arises from the decay of ${\ensuremath{\pi}}^{0}$ mesons produced in the fragmentation of annihilation final states shows a severe cutoff close to the value of the WIMP mass. An even more spectacular signature appears for the monochromatic gamma-ray components, generated by WIMP annihilations into two-body final states containing a photon: the combined effect of cosmological redshift and absorption along the line of sight produces sharp bumps, peaked at the rest frame energy of the lines and asymmetrically smeared to lower energies. The level of the flux depends both on the particle physics scenario for WIMP dark matter (we consider, as our template case, the lightest supersymmetric particle in a few supersymmetry breaking schemes), and on the question of how dark matter clusters. Uncertainties introduced by the latter are thoroughly discussed implementing a realistic model inspired by results of the state-of-the-art N-body simulations and semianalytic modeling in the cold dark matter structure formation theory. We also address the question of the potential gamma-ray background originating from active galaxies, presenting a novel calculation and critically discussing the assumptions involved and the induced uncertainties. Furthermore, we apply a realistic model for the absorption of gamma-rays on the optical and near-IR intergalactic radiation field to derive predictions for both the signal and background. Comparing the two, we find that there are viable configurations, in the combined parameter space defined by the particle physics setup and the structure formation scenario, for which the WIMP induced extragalactic gamma-ray signal will be detectable in the new generation of gamma-ray telescopes such as GLAST.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/d45c8d1010e9e81bf589ae13ec9c0c16ca711435

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Nuclear and High Energy Physics

Citations in the corpus

Mass Deficits, Stalling Radii, and the Merger Histories of Elliptical Galaxies (2006, background): “One of the proposed search strategies is to identify a component of the diffuse gamma-ray background that is generated by dark matter annihilations in halos at all redshifts (Ullio et al. 2002; Taylor & Silk 2003).”
The first WIMPy halos (2005, background): “[8, 10]) and the extra-galactic gamma-ray signal depends on the clumpiness of the WIMP distribution [11].”
THE ORIGIN OF THE EXTRAGALACTIC GAMMA-RAY BACKGROUND AND IMPLICATIONS FOR DARK MATTER ANNIHILATION (2015, methodology): “…of processes generating a truly diffuse background, like intergalactic shocks (e.g. Loeb & Waxman 2000; Miniati 2002), γ-ray emission induced by ultra-high energy cosmic rays in intergalactic space (see e.g. Bhattacharjee & Sigl 2000), and dark matter (DM) annihilation (e.g. Ullio et al. 2002).”
Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects (2012, background): “g. 4 the result of a large scan (for details, see Ref. [299]) over the parameter space of the cMSSM and a phenomenological MSSM-7, keeping only neutralino DM models where IB,γγand γZ photons for Eγ ∈ [120,140] GeV dominate the secondary contribution by a factor of at least 5; for reference, we also ”
THE FERMI-LAT HIGH-LATITUDE SURVEY: SOURCE COUNT DISTRIBUTIONS AND THE ORIGIN OF THE EXTRAGALACTIC DIFFUSE BACKGROUND (2010, background): “Indeed, super-symmetric theories with R-parity predict that the lightest DM particles (i.e., the neutralinos) are stable and can annihilate into GeV γ -rays (e.g. Jungman et al. 1996; Bergstr¨om 2000; Ullio et al. 2002; Ahn et al. 2007).”
Sensitivity projections for dark matter searches with the Fermi large area telescope (2016, methodology): “Following Ackermann et al. (2014b), predictions of the cosmological annihilation signal were obtained using both the halo model (Ullio et al. 2002; Fornasa et al. 2013) and the power spectrum approach (Serpico et al. 2012; Sefusatti et al. 2014).”
Dark matter annihilation in the halo of the Milky Way (2003, methodology): “8 were computed following Bergström et al. (1998), Baltz et al. (2000), Ullio et al. (2002) and TO.”
GeV OBSERVATIONS OF STAR-FORMING GALAXIES WITH THE FERMI LARGE AREA TELESCOPE (2012, background): “Finally, a portion of the IGRB may originate from ‘new physics’ processes involving, for instance, the annihilation or decay of dark matter particles (Bergström et al. 2001; Ullio et al. 2002; Taylor & Silk 2003).”
Numerical simulations of the dark universe: State of the art and the next decade (2012, background): “gamma-ray radiation produced by DM annihilations throughout cosmic history [86].”
Characterization of subhalo structural properties and implications for dark matter annihilation signals (2016, background): “…these problems, although the relevant gravitational physics can only be treated in an approximate way (Taylor & Babul 2001; Benson et al. 2002; Ullio et al. 2002; Taffoni et al. 2003; Zentner & Bullock 2003; Peñarrubia & Benson 2005; Oguri & Lee 2004; Taylor & Babul 2005b,a,b; van den Bosch…”
CONTRIBUTION OF GAMMA-RAY-LOUD RADIO GALAXIES’ CORE EMISSIONS TO THE COSMIC MeV AND GeV GAMMA-RAY BACKGROUND RADIATION (2011, background): “…AGNs (Inoue et al. 2008; Inoue & Totani 2009), and GeV mass-scale DM annihilation or decay (see, e.g., Jungman et al. 1996; Bergström 2000; Ullio et al. 2002; Oda et al. 2005; Ando & Komatsu 2006; Horiuchi & Ando 2006; Ando et al. 2007; Ahn et al. 2007; Ando 2009; Kawasaki et al. 2009).”
Constraining light dark matter with diffuse X-ray and gamma-ray observations (2013, background): “On the other hand, extragalactic annihilations resulting from DM substructure at low redshift may contribute a significant amount to the photon flux since it scales as the square of the DM density [71].”