Conservative upper limits on WIMP annihilation cross section from Fermi-LAT<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>γ</mml:mi></mml:math>rays

Calore, Francesca; Romeri, Valentina De; Donato, Fiorenza

doi:10.1103/physrevd.85.023004

Cited by 29 publications

(52 citation statements)

References 80 publications

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“…Unresolved blazars and millisecond pulsars also need to be withdrawn from the gamma ray measurements to yield the EGB. This is also the case for star-forming galaxies and secondary electromagnetic showers induced by ultra-high energy cosmic rays, both components being highly model dependent as mentioned by Calore et al (2012). The IceCube collaboration has set limits on the DM annihilation cross section by searching for high energy neutrinos in nearby galaxies and galaxy clusters (Aartsen et al 2013).…”

Section: Introductionmentioning

confidence: 99%

A new look at the cosmic ray positron fraction

Boudaud

Aupetit

Caroff

et al. 2015

A&A

130

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Context. The positron fraction in cosmic rays has recently been measured with improved accuracy up to 500 GeV, and it was found to be a steadily increasing function of energy above ∼10 GeV. This behaviour contrasts with standard astrophysical mechanisms, in which positrons are secondary particles, produced in the interactions of primary cosmic rays during their propagation in the interstellar medium. The observed anomaly in the positron fraction triggered a lot of excitement, as it could be interpreted as an indirect signature of the presence of dark matter species in the Galaxy, the so-called weakly interacting massive particles (WIMPs). Alternatively, it could be produced by nearby sources, such as pulsars. Aims. These hypotheses are probed in light of the latest AMS-02 positron fraction measurements. As regards dark matter candidates, regions in the annihilation cross section to mass plane, which best fit the most recent data, are delineated and compared to previous measurements. The explanation of the anomaly in terms of a single nearby pulsar is also explored. Methods. The cosmic ray positron transport in the Galaxy is described using a semi-analytic two-zone model. Propagation is described with Green functions as well as with Bessel expansions. For consistency, the secondary and primary components of the positron flux are calculated together with the same propagation model. The above mentioned explanations of the positron anomaly are tested using χ 2 fits. The numerical package MicrOMEGAs is used to model the positron flux generated by dark matter species. The description of the positron fraction from conventional astrophysical sources is based on the pulsar observations included in the Australia Telescope National Facility (ATNF) catalogue. Results. The masses of the favoured dark matter candidates are always larger than 500 GeV, even though the results are very sensitive to the lepton flux. The Fermi measurements point systematically to much heavier candidates than the recently released AMS-02 observations. Since the latter are more precise, they are much more constraining. A scan through the various individual annihilation channels disfavours leptons as the final state. On the contrary, the agreement is excellent for quark, gauge boson, or Higgs boson pairs, with best-fit masses in the 10 to 40 TeV range. The combination of annihilation channels that best matches the positron fraction is then determined at fixed WIMP mass. A mixture of electron and tau lepton pairs is only acceptable around 500 GeV. Adding b-quark pairs significantly improves the fit up to a mass of 40 TeV. Alternatively, a combination of the four-lepton channels provides a good fit between 0.5 and 1 TeV, with no muons in the final state. Concerning the pulsar hypothesis, the region of the distance-to-age plane that best fits the positron fraction for a single source is determined. Conclusions. The only dark matter species that fulfils the stringent gamma ray and cosmic microwave background bounds is a particle annihilating into...

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Section: Introductionmentioning

confidence: 99%

A new look at the cosmic ray positron fraction

Boudaud

Aupetit

Caroff

et al. 2015

A&A

130

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“…Though its very nature is still unexplained, it is reasonable to believe it to be the superposition of (mainly) extragalactic unresolved point sources and, to a lesser extent, of astrophysical diffuse processes (see Ref. [17] and Sec. II for a detailed discussion).…”

Section: Introductionmentioning

confidence: 99%

“…1 Previous upper limits on the DM annihilation cross section from the high latitudes γ-ray emission were derived e.g. in [17], by subtracting from the IGRB [15] the minimum estimated fluxes for the most significant unresolved source populations. The faint but numerous population of Active Galactic Nuclei (AGN) whose jet axes have a large viewing angle with respect to the line of sight (l.o.s.)…”

Section: Introductionmentioning

confidence: 99%

Constraining dark matter annihilation with the isotropicγ-ray background: Updated limits and future potential

et al. 2014

Self Cite

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The nature of the isotropic γ-ray background (IGRB) measured by the Large Area Telescope (LAT) on the Fermi γ-ray space telescope (Fermi) remains partially unexplained. Non-negligible contributions may originate from extragalactic populations of unresolved sources such as blazars, star-forming galaxies or galactic millisecond pulsars. A recent prediction of the diffuse γ-ray emission from active galactic nuclei (AGN) with a large viewing angle with respect to the line of sight has demonstrated that this faint but numerous population is also expected to contribute significantly to the total IGRB intensity. A more exotic contribution to the IGRB invokes the pair annihilation of dark matter (DM) weakly interacting massive particles (WIMPs) into γ rays. In this work, we evaluate the room left for galactic DM at high latitudes (> 10 ∘ ) by including photons from both prompt emission and inverse Compton scattering, emphasizing the impact of the newly discovered contribution from misaligned AGN (MAGN) for such an analysis. Summing up all significant galactic and extragalactic components of the IGRB, we find that an improved understanding of the associated astrophysical uncertainties is still mandatory to put stringent bounds on thermally produced DM. On the other hand, we also demonstrate that the IGRB has the potential to be one of the most competitive future ways to test the DM WIMP hypothesis, once the present uncertainties are even slightly reduced. In fact, if MAGN contribute even at 90% of the maximal level consistent with our current understanding, thermally produced WIMPs would be severely constrained as DM candidates for masses up to several TeV.

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“…The γ -rays produced by DM annihilation or decay can also contribute to EGB (Ullio et al 2002;Zavala et al 2010Zavala et al , 2011Cirelli et al 2011;Fornasa et al 2013). However, the fact that the EGB energy spectrum is compatible with a power law, without any evident spectral feature, suggests that DM cannot play a leading role in the whole energy range (Abdo et al 2010a;Calore et al 2012). In the angular anisotropies of the EGB emission, the DM also plays a subdominant role: indeed, a detection of a significant autocorrelation angular PS has been recently reported (Ackermann et al 2012a; for multipoles > 100, which is the range of interest for our analysis, since there the contamination of the Galactic foreground can be neglected), but the features of such a signal (in particular its independence on multipole and energy) seem to indicate an interpretation in terms of blazars (Cuoco et al 2012;Harding & Abazajian 2012).…”

Section: Introductionmentioning

confidence: 99%

A Novel Approach in the Weakly Interacting Massive Particle Quest: Cross-Correlation of Gamma-Ray Anisotropies and Cosmic Shear

Camera

Fornasa

Fornengo

et al. 2013

ApJ

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Both cosmic shear and cosmological gamma-ray emission stem from the presence of dark matter (DM) in the universe: DM structures are responsible for the bending of light in the weak-lensing regime and those same objects can emit gamma rays, either because they host astrophysical sources (active galactic nuclei or star-forming galaxies) or directly by DM annihilations (or decays, depending on the properties of the DM particle). Such gamma rays should therefore exhibit strong correlation with the cosmic shear signal. In this Letter, we compute the crosscorrelation angular power spectrum of cosmic shear and gamma rays produced by the annihilation/decay of weakly interacting massive particle DM, as well as by astrophysical sources. We show that this observable provides novel information on the composition of the extragalactic gamma-ray background (EGB), since the amplitude and shape of the cross-correlation signal strongly depend on which class of sources is responsible for the gamma-ray emission. If the DM contribution to the EGB is significant (at least in a definite energy range), although compatible with current observational bounds, its strong correlation with the cosmic shear makes such signal potentially detectable by combining Fermi Large Area Telescope data with forthcoming galaxy surveys, like the Dark Energy Survey and Euclid. At the same time, the same signal would demonstrate that the weak-lensing observables are indeed due to particle DM matter and not to possible modifications of general relativity.

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Conservative upper limits on WIMP annihilation cross section from Fermi-LATγrays

Cited by 29 publications

References 80 publications

A new look at the cosmic ray positron fraction

A new look at the cosmic ray positron fraction

Constraining dark matter annihilation with the isotropicγ-ray background: Updated limits and future potential

A Novel Approach in the Weakly Interacting Massive Particle Quest: Cross-Correlation of Gamma-Ray Anisotropies and Cosmic Shear

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