Wimp searches with gamma rays in the Fermi era: Challenges, methods and results

Conrad, J.; Cohen-Tanugi, J.; Strigari, Louis E.

doi:10.1134/s1063776115130099

Cited by 55 publications

(61 citation statements)

References 253 publications

(334 reference statements)

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“…One of the most active lines of research in DM physics is that of indirect searches of the DM annihilation products (gammarays, neutrinos and antimatter) in different astrophysical regions (Conrad et al 2015). The flux of this potential DM signal is proportional to the square of the DM density and thus, regions where the DM density is higher are, in principle, the most promising targets.…”

Section: Contextmentioning

confidence: 99%

Characterization of subhalo structural properties and implications for dark matter annihilation signals

Moliné

Sánchez‐Conde

Palomares‐Ruiz

et al. 2017

Mon. Not. R. Astron. Soc.

164

295

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A prediction of the standard ΛCDM cosmological model, also confirmed by N-body simulations, is that dark matter (DM) halos are teeming with numerous self-bound substructure, or subhalos. The precise properties of these subhalos represent important probes of the underlying cosmological model. In this work, we use data from the N-body Via Lactea II and ELVIS Milky Way-size simulations to learn about the structure of subhalos with masses 10 6 − 10 11 h −1 M . Thanks to a superb subhalo statistics, by taking a profileindependent approach, we study subhalo properties as a function of the distance to the host halo center and subhalo mass, and provide a set of fits that, including both dependences, accurately describe the subhalo structure. With this at hand, we also investigate the role of subhalos on the search for DM via its annihilation products. Indeed, previous work has shown that subhalos are expected to boost the DM signal of their host halos significantly. Yet, these works have traditionally assumed that subhalos exhibit similar structural properties than those of field halos of the same mass, while it is well known from simulations that subhalos are more concentrated. Building upon the results from our N-body data analysis, we refine the substructure boost model of Sánchez-Conde & Prada (2014). We find boost values that are a factor 2 − 3 higher than previous ones. We further refine our boost model to include unavoidable tidal stripping effects on the subhalo population. For field halos, this only introduces a moderate (∼ 20% − 30%) suppression of the boost. Yet, for subhalos like those hosting the dwarf satellite galaxies of the Milky Way, tidal stripping does play a critical role, the total boost for these objects being only at the level of a few tens of percent in the most optimistic cases. Finally, we provide a parametrization of the boost factor for field halos that can be safely applied over a wide halo mass range.

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Section: Contextmentioning

confidence: 99%

Characterization of subhalo structural properties and implications for dark matter annihilation signals

Moliné

Sánchez‐Conde

Palomares‐Ruiz

et al. 2017

Mon. Not. R. Astron. Soc.

164

295

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“…A major strategy for the indirect detection of dark matter is the search for photons arising from dark matter annihilation in dwarf spheroidal galaxies (dSphs) [1]. The dark matter halo masses of dSphs are well constrained from stellar kinematics [2][3][4][5], and the systematic uncertainties associated with the expected backgrounds [6] are relatively small compared with other astrophysical targets and channels used in indirect detection.…”

Section: Introductionmentioning

confidence: 99%

Sommerfeld-enhanced J -factors for dwarf spheroidal galaxies

2017

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For models in which dark matter annihilation is Sommerfeld-enhanced, the annihilation cross section increases at low relative velocities. Dwarf spheroidal galaxies (dSphs) have low characteristic dark matter particle velocities and are thus ideal candidates to study such models. In this paper we model the dark matter phase space of dSphs as isotropic and spherically-symmetric, and determine the J-factors for several of the most important targets for indirect dark matter searches. For Navarro-Frenk-White density profiles, we quantify the scatter in the J-factor arising from the astrophysical uncertainty in the dark matter potential. We show that, in Sommerfeld-enhanced models, the ordering of the most promising dSphs may be different relative to the standard case of velocity-independent cross sections. This result can have important implications for derived upper limits on the annihilation cross section, or on possible signals, from dSphs.

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“…The dSph constraint derived from bb rules out the entire m χ − σv plane in the parameter space, while the constraint from τ + τ − allows a small fraction of it. In a similar manner, the φφ → 4τ final state allows for a wider range of DM mass (15)(16)(17)(18)(19)(20)(21)(22)(23), as opposed to a very narrow window (8.4-10.4 GeV) for the τ + τ − final state. There is a slightly larger range of σv values preferred by the 4τ channel (0.56 − 1.19 × 10 −26 cm 3 /s) relative to the 2τ channel (0.31 − 0.43 × 10 −26 cm 3 /s).…”

Section: Resultsmentioning

confidence: 99%

“…Dwarf spheroidal galaxies (dSphs) of the Milky Way are quintessential target for indirect DM searches [21,22], and provide an independent cross check on a possible DM signal hinted at near the Galactic center. Indeed the lack of excess gamma-ray signal from dSphs imposes constraints on DM annihilation cross-section [23], and also strongly constrains DM interpretations of the GCE for a variety of different annihilation channels with 2 body final states.…”

Section: Introductionmentioning

confidence: 99%

Confronting Galactic center and dwarf spheroidal gamma-ray observations with cascade annihilation models

et al. 2015

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Many particle dark matter models predict that the dark matter undergoes cascade annihilations, i.e. the annihilation products are 4-body final states. In the context of model-independent cascade annihilation models, we study the compatibility of the dark matter interpretation of the Fermi-LAT Galactic center gamma-ray emission with null detections from dwarf spheroidal galaxies. For canonical values of the Milky Way density profile and the local dark matter density, we find that the dark matter interpretation to the Galactic center emission is strongly constrained. However, uncertainties in the dark matter distribution weaken the constraints and leave open dark matter interpretations over a wide range of mass scales.

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Wimp searches with gamma rays in the Fermi era: Challenges, methods and results

Cited by 55 publications

References 253 publications

Characterization of subhalo structural properties and implications for dark matter annihilation signals

Characterization of subhalo structural properties and implications for dark matter annihilation signals

Sommerfeld-enhanced J -factors for dwarf spheroidal galaxies

Confronting Galactic center and dwarf spheroidal gamma-ray observations with cascade annihilation models

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