Cosmic-ray antiprotons, positrons, and gamma rays from halo dark matter annihilation

1988 ◽  
Vol 325 ◽  
pp. 16 ◽  
Author(s):  
S. Rudaz ◽  
F. W. Stecker
Keyword(s):  
Dark Matter ◽  
Gamma Rays ◽  
Cosmic Ray ◽  
Dark Matter Annihilation

An excess radio signal in the Abell 4038 cluster

2020 ◽  
Vol 500 (4) ◽  
pp. 5583-5588
Author(s):  
Man Ho Chan ◽  
Chak Man Lee
Keyword(s):  
Dark Matter ◽  
Spectral Data ◽  
Cross Section ◽  
Radio Signal ◽  
Dark Matter Particle ◽  
Cosmic Ray ◽  
Annihilation Cross Section ◽  
Radio Continuum ◽  
Test Statistic ◽  
Dark Matter Annihilation

ABSTRACT In the past decade, various instruments, such as the Large Area Telescope (LAT) on the Fermi Gamma Ray Space Telescope, the Alpha Magnetic Spectrometer (AMS) and the Dark Matter Particle Explorer(DAMPE), have been used to detect the signals of annihilating dark matter in our Galaxy. Although some excesses of gamma rays, antiprotons and electrons/positrons have been reported and are claimed to be dark matter signals, the uncertainties of the contributions of Galactic pulsars are still too large to confirm the claims. In this paper, we report on a possible radio signal of annihilating dark matter manifested in the archival radio continuum spectral data of the Abell 4038 cluster. By assuming a thermal annihilation cross-section and comparing the dark matter annihilation model with the null hypothesis (cosmic ray emission without dark matter annihilation), we obtain very large test statistic (TS) values, TS > 45, for four popular annihilation channels, which correspond to more than 6σ statistical preference. This reveals a possible potential signal of annihilating dark matter. In particular, our results are also consistent with the recent claims of dark matter mass, m ≈ 30–50 GeV, annihilating via the $\rm b\bar{b}$ quark channel with the thermal annihilation cross-section. However, at this time, we cannot exclude the possibility that a better background cosmic ray model could explain the spectral data without recourse to dark matter annihilations.

scholarly journals A possible radio signal of annihilating dark matter in the Abell 4038 cluster

2019 ◽  
Vol 495 (1) ◽  
pp. L124-L128 ◽  
Author(s):  
Man Ho Chan ◽  
Chak Man Lee
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Radio Signal ◽  
Dark Matter Particle ◽  
Cosmic Ray ◽  
Annihilation Cross Section ◽  
Radio Continuum ◽  
Test Statistic ◽  
Large Area ◽  
Dark Matter Annihilation

ABSTRACT In the past decade, some telescopes [e.g. Fermi-Large Area Telescope (LAT), Alpha Magnetic Spectrometer(AMS), and Dark Matter Particle Explorer(DAMPE)] were launched to detect the signals of annihilating dark matter in our Galaxy. Although some excess of gamma-rays, antiprotons, and electrons/positrons have been reported and claimed as dark matter signals, the uncertainties of Galactic pulsars’ contributions are still too large to confirm the claims. In this Letter, we report a possible radio signal of annihilating dark matter manifested in the archival radio continuum spectral data of the Abell 4038 cluster. By assuming the thermal annihilation cross-section and comparing the dark matter annihilation model with the null hypothesis (cosmic ray emission without dark matter annihilation), we get very large test statistic values >45 for four popular annihilation channels, which correspond to more than 6.5σ statistical preference. This provides a very strong evidence for the existence of annihilating dark matter. In particular, our results also support the recent claims of dark matter mass m ≈ 30–50 GeV annihilating via the bb̄ quark channel with the thermal annihilation cross-section.

scholarly journals NEUTRINO EMISSION FROM DARK MATTER ANNIHILATION/DECAY IN LIGHT OF COSMIC e± AND $\bar{p}$ DATA

2012 ◽  
Vol 27 (06) ◽  
pp. 1250024 ◽  
Author(s):  
JIE LIU ◽  
QIANG YUAN ◽  
XIAOJUN BI ◽  
HONG LI ◽  
XINMIN ZHANG
Keyword(s):  
Dark Matter ◽  
Branching Ratio ◽  
Cosmic Ray ◽  
Current Data ◽  
Neutrino Emission ◽  
Dark Matter Annihilation ◽  
Text Data ◽  
Self Consistent ◽  
Γ Rays ◽  
Global Fitting

A self-consistent global fitting method based on the Markov Chain Monte Carlo technique to study the dark matter (DM) property associated with the cosmic ray electron/positron excesses was developed in our previous work. In this work we further improve the previous study to include the hadronic branching ratio of DM annihilation/decay. The PAMELA [Formula: see text] data are employed to constrain the hadronic branching ratio. We find that the 95% (2σ) upper limits of the quark branching ratio allowed by the PAMELA [Formula: see text] data is ~0.032 for DM annihilation and ~0.044 for DM decay, respectively. This result shows that the DM coupling to pure leptons is indeed favored by the current data. Based on the global fitting results, we further study the neutrino emission from DM in the galactic center. Our predicted neutrino flux is some smaller than previous works since the constraint from γ-rays is involved. However, it is still capable to be detected by the forthcoming neutrino detector such as IceCube. The improved points of the present study compared with previous works include: (1) the DM parameters, both the particle physical ones and astrophysical ones, are derived in a global fitting way, (2) constraints from various species of data sets, including γ-rays and antiprotons are included, and (3) the expectation of neutrino emission is fully self-consistent.

scholarly journals A MODEL-INDEPENDENT METHOD TO STUDY DARK MATTER INDUCED LEPTONS AND GAMMA RAYS

2012 ◽  
Vol 27 (35) ◽  
pp. 1250206 ◽  
Author(s):  
MINGXING LUO ◽  
LIUCHENG WANG ◽  
GUOHUAI ZHU
Keyword(s):  
Dark Matter ◽  
Compton Scattering ◽  
Gamma Rays ◽  
Particle Physics ◽  
Cosmic Ray ◽  
Propagation Model ◽  
Strong Constraint ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
Model Independent

By using recent data, we directly determine the dark matter (DM)-induced e± spectrum at the source from experimental measurements at the earth, without reference to specific particle physics models. The DM-induced gamma rays emitted via inverse Compton scattering are then obtained in a model-independent way. However, the results depend on the choice of the astrophysical e± background, which is not reliably known. Nevertheless, we calculate, as an illustration, the fluxes of gamma rays from the Fornax cluster in the decaying DM scenario with various astrophysical e± backgrounds. Without any assumptions on details of the DM model, the predictions turn out to be either in disagreement with or only marginally below the upper limits measured recently by the Fermi-LAT Collaboration. In addition, these DM-induced ICS gamma rays in the GeV range are shown to be almost independent of choices of cosmic ray propagation model and of DM density profile, when a given astrophysical e± background is assumed. This provides a strong constraint on decaying DM scenario as the gamma rays may be produced in other processes besides inverse Compton scattering, such as the bremsstrahlung and neutral pion decays.

scholarly journals Remnants of Galactic Subhalos and Their Impact on Indirect Dark-Matter Searches

Galaxies ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 65 ◽  
Author(s):  
Martin Stref ◽  
Thomas Lacroix ◽  
Julien Lavalle
Keyword(s):  
Dark Matter ◽  
Computer Simulations ◽  
Gamma Rays ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Dark Matter Particle ◽  
Cosmic Ray ◽  
Tidal Disruption ◽  
Large Numbers ◽  
Boost Factor

Dark-matter subhalos, predicted in large numbers in the cold-dark-matter scenario, should have an impact on dark-matter-particle searches. Recent results show that tidal disruption of these objects in computer simulations is overefficient due to numerical artifacts and resolution effects. Accounting for these results, we re-estimated the subhalo abundance in the Milky Way using semianalytical techniques. In particular, we showed that the boost factor for gamma rays and cosmic-ray antiprotons is increased by roughly a factor of two.

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