Phenomenology of dark matter indirect detection

Jordan Koechler

REVIEW 3 major objections 5 minor 10 references

Phenomenology of dark matter indirect detection

T0 review · 3 major / 5 minor · reviewed 2026-08-12 · deepseek-v4-flash

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Pith's one-line read This thesis claims that inverse Compton scattering of dark-matter-produced electrons on Galactic light yields the most stringent existing X-ray constraints on sub-GeV dark matter, and that cosmic-ray reacceleration extends them below 20…

desk verdict Decent PhD thesis compiling three published papers; the main X-ray constraints hold, but the sub-20 MeV improvement rests on an admitted extrapolation. read the letter →

arxiv 2411.11928 v1 pith:XHOFQ5XV submitted 2024-11-18 hep-ph astro-ph.COastro-ph.HE

Jordan Koechler This is my paper · ORCID

classification hep-phastro-ph.COastro-ph.HE

keywords darkmatterindirectdetectionsub-GeVinverseComptonscatteringX-rayconstraintscosmic-raypropagationreaccelerationprimordialblackholes

topics Dark Matter

open problems Dark Matter

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This thesis sets out to make light dark matter visible by watching the X-rays its debris produces while still inside the Galaxy. Sub-GeV dark matter is normally hard to probe indirectly: its annihilation and decay produce electrons and positrons that are screened by the solar wind at Earth, and its prompt gamma rays fall in a sensitivity gap between roughly 100 keV and 100 MeV. The thesis argues that inverse Compton scattering of those electrons off the Galactic light bath converts them into hard X-rays that current observatories see well, and demonstrates that the point-source-cleaned XMM-Newton whole-sky dataset yields the most stringent existing limits on decaying sub-GeV dark matter — a decay half-life above $10^{27}$ s for masses of roughly 50 MeV to 1 GeV, up to three orders of magnitude stronger than earlier bounds — and the most stringent indirect limits on annihilation above roughly 180 MeV, with ⟨σv⟩ near $10^{-28}$ $cm^{3}$/s for masses of roughly 20 MeV to 1 GeV. A follow-up analysis with a realistic cosmic-ray propagation model shows that reacceleration lifts low-energy electrons into the X-ray-producing range, extending the limits to masses below 20 MeV. The same secondary-radiation logic is then applied to evaporating primordial black holes, with the 511 keV line giving the strongest of the three probes. If these results hold, they narrow the open parameter space for light dark matter and give X-ray telescopes a concrete role in closing the MeV gap.

What carries the argument

The engine of the argument is inverse Compton scattering — the process by which a fast electron hands energy to a low-energy photon, the reverse of how photons push electrons — acting on the e± injected by dark matter annihilation, decay, or black-hole evaporation. Scattered off the Galactic ambient light (the cosmic microwave background, starlight, and infrared dust emission), sub-GeV electrons produce hard X-rays in the keV band that current X-ray telescopes measure well, bypassing the sensitivity gap in gamma-ray instruments between roughly 100 keV and 100 MeV and the solar-wind screening that suppresses low-energy electrons at Earth. Chapters 3 and 4 differ in how the electron density is computed: a deliberately conservative model that keeps only energy losses in Chapter 3, versus a full numerical propagation treatment in Chapter 4 in which momentum-space diffusion (reacceleration, characterized by an Alfvén speed fit to cosmic-ray data) boosts low-energy electrons into the X-ray-producing range. Every limit is derived by comparing predicted fluxes to data with a one-sided χ² test that ignores astrophysical backgrounds, which the thesis presents as making the bounds conservative.

What would settle it

Measure cosmic-ray secondary-to-primary ratios (for instance boron-to-carbon) at energies below about 100 MeV with AMS-02 or a successor experiment to fix the diffusion coefficient in the sub-GeV regime; if the coefficient does not rise toward low energies approximately as $β^{-0}$.75, the claimed extension of the dark-matter limits below 20 MeV would weaken substantially. A second check is to model the full astrophysical X-ray background in the XMM-Newton rings: if that background already saturates the observed flux, the derived annihilation and decay bounds would loosen.

Watch

Extended reading notes

Core claim

The central claim, stated on the thesis's own terms, is that inverse Compton scattering of dark-matter-produced electrons and positrons on the Galactic radiation field turns sub-GeV dark matter into a detectable keV X-ray flux, so that X-ray observatories can probe masses and channels that gamma-ray and cosmic-ray searches miss. Comparing predicted spectra against the point-source-cleaned XMM-Newton whole-sky rings gives, for annihilation into e+e-, the bound ⟨σv⟩ ≲ $10^{-28}$ $cm^{3}$/s for dark matter masses between about 20 MeV and 1 GeV, and for decay into e+e-, a half-life τ ≳ $10^{27}$ s for masses between about 50 MeV and 1 GeV, improving on earlier limits by up to three orders of magnitude. The thesis further argues that a realistic propagation treatment, including stochastic reacceleration of sub-GeV electrons by magnetic turbulence, lifts low-mass dark matter's electrons into the X-ray-producing range and thereby extends the constraints below 20 MeV, where they had no purchase before. The same machinery applied to primordial black hole evaporation produces three probes, of which the 511 keV line from positron annihilation in the interstellar medium is claimed to be the strongest and most dependable.

Load-bearing premise

The claimed strengthening below 20 MeV rests on the propagation model adopted in Section 4.1.1 — a diffusion coefficient that rises as $β^{-0}$.75 at low energies with an Alfvén speed of 13.4 km/s, both fit to AMS-02 data — and, as the thesis itself states, there is no reliable measurement of the diffusion coefficient below roughly 100 MeV, so the size of the reacceleration boost is an extrapolation.

Editorial extensions

If this is right

Thermal-relic sub-GeV dark matter annihilating to e+e- with s-wave (velocity-independent) cross sections is excluded for masses of roughly 20 MeV to 1 GeV.
Decaying sub-GeV dark matter must have a half-life above about 10^27 s up to masses of 1 GeV, tightening previous bounds by up to three orders of magnitude.
Reacceleration extends the reach of X-ray telescopes below 20 MeV, into a window that Voyager 1 cosmic-ray data and CMB constraints cover only partially.
The same secondary-emission logic constrains primordial black holes through their evaporation products, with the 511 keV line giving the strongest of the three probes.
Because the limits deliberately ignore astrophysical backgrounds, including them in a future analysis can only strengthen the resulting bounds.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

The same pipeline could be pointed at the next generation of all-sky X-ray surveys and at planned MeV-band instruments, turning the current extrapolated sub-20 MeV region into a calibrated measurement.
A sharper determination of the inner-Galaxy dark matter profile — for example from stellar kinematics or gravitational lensing — would directly shrink the dominant uncertainty, which the thesis quantifies as up to two orders of magnitude on the annihilation limits.
If the reacceleration boost is real, the same mechanism should be visible in the 511 keV Galactic bulge line and in future low-energy positron measurements, offering a cross-check of the sub-20 MeV limits that is independent of the X-ray data.

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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

Dear [Colleague],

This is a PhD thesis, not a research paper, and it should be judged as such. It compiles three already-published papers into a coherent manuscript, with two introductory chapters on dark matter and indirect detection. If you're looking for new results, there are none—the author says so explicitly. But the thesis is well written, honest, and technically sound.

Where it earns credit: the XMM-Newton constraints on sub-GeV annihilation/decay are carefully derived with a conservative one-sided chi-square that ignores astrophysical backgrounds, and the authors quantify the impact of the DM profile, gas density, radiation field, and propagation uncertainties. The Chapter 3 bounds above ~20 MeV (annihilation) and ~50 MeV (decay) are robust. The use of DRAGON2 and HERMES in Chapter 4 is state of the art, and the discussion of propagation parameter uncertainties is transparent.

Soft spots: the low-mass improvement below ~20 MeV in Chapter 4 depends on the diffusion coefficient's beta^-0.75 rise and v_A=13.4 km/s, both extrapolated from AMS-02 secondary ratios measured above a few hundred MeV/n. The thesis itself admits in Section 4.1.1 that 'different assumptions of the diffusion setup are able to reproduce the current local data.' If those parameters change at sub-GeV energies, the reacceleration boost weakens, and the low-mass limits would relax. That caveat is in the text, not hidden, but it means the sub-20 MeV numbers are conditional. The main constraints above 20 MeV are unaffected. Also note the thesis uses some data from private communication (Suzaku), which limits reproducibility, though that's minor.

Who's it for: graduate students entering the field will benefit from the pedagogical overview; practitioners will use the published papers directly. For a journal, there is no new result to referee. As a thesis, it already underwent a defense review. My recommendation: don't send this to peer review as a new research contribution; if the author wants to advertise the low-mass constraints, they should be presented with the propagation-model caveat front and center.

Referee Report

3 major / 5 minor

Summary. This PhD thesis presents a phenomenological study of indirect dark-matter detection, with the main new results in Chapters 3-5. Chapter 3 computes prompt and inverse-Compton X-ray emission from sub-GeV dark matter annihilating or decaying into e+e-, mu+mu-, and pi+pi-, and compares the predicted fluxes with INTEGRAL, NuSTAR, Suzaku, and XMM-Newton data using a one-sided, conservative chi-square statistic. It reports that the XMM-Newton whole-sky data set gives the most stringent constraints, with <sigma v> ~ 1e-28 cm^3/s for annihilating DM in the 20 MeV to 1 GeV mass range and decay lifetimes tau > 1e27 s for masses between 50 MeV and 1 GeV. Chapter 4 replaces the minimal energy-loss-only propagation model with a DRAGON2-based setup including spatial diffusion and reacceleration, claiming large improvements for DM masses below about 20 MeV. Chapter 5 extends the same X-ray and electron-positron techniques to primordial black hole evaporation, with the 511 keV line providing the strongest PBH constraint.

Significance. The Chapter 3 results, if they hold, are a valuable phenomenological contribution. The analysis uses a large public XMM-Newton archive, the statistical procedure is conservative in direction because it does not fit an astrophysical background, and the authors quantify the impact of DM profile, gas density, radiation field, and magnetic-field choices. The decay limits improve existing bounds by up to three orders of magnitude, which is a strong and falsifiable claim. The use of publicly available codes (DRAGON2, HERMES) and response matrices supports reproducibility. The main weakness is that the Chapter 4 improvement below about 20 MeV depends on an extrapolation of the low-energy diffusion coefficient and Alfven speed that is not directly constrained by cosmic-ray data; this part of the claim needs to be presented as model-dependent unless additional robustness tests are provided.

major comments (3)

[Section 4.1.1, Eq. (4.1), Table 4.1] The claimed large improvement of the XMM-Newton limits for mDM below about 20 MeV is not robust to the current uncertainties in low-energy cosmic-ray transport. The diffusion coefficient in Eq. (4.1), D(R) = D0 beta^eta (R/R0)^delta [1 + (R/Rb)^(Delta delta/s)]^(-s) with eta = -0.75, and the Alfven velocity v_A = 13.4 km/s are fit to AMS-02 B, Be, and Li data whose lowest measured energies are near a few hundred MeV/n. The thesis itself states in Section 4.1.1 that 'there is no robust estimation of the diffusion coefficient below ? 100 MeV since different assumptions of the diffusion setup are able to reproduce the current local data.' Because reacceleration is exactly the effect that moves sub-20 MeV DM-produced e± into the XMM-Newton energy band (Fig. 4.3), the factor-of-several improvement shown in Figs. 4.4-4.7 for mDM < 20 MeV is an extrapolation rather than a measured constraint. Please add limits for at least one alternative low-energy diffusion model (for example eta = 0 or eta = 1 with the same v_A, as well as a low-v_A variant) to the main comparison figures, and clearly mark the sub-20 MeV region as model-dependent.
[Section 3.3, Figs. 3.8, 3.9, 3.11] The headline 'most stringent constraints' is presented in the comparison figures without the uncertainty band. Figure 3.11 shows that the combined astrophysical uncertainties can move the annihilation limits by up to two orders of magnitude, and the text in Section 3.3 says the constraints 'can (generously) vary within two orders of magnitude.' Since the comparison against CMB and Leo T bounds in Fig. 3.8 is close in some mass ranges, the single curves in Figs. 3.8 and 3.9 do not by themselves establish that the claim holds for non-fiducial but plausible DM profiles and radiation-field normalisations. Please overlay the uncertainty band, at least for the e+e- channel, on the comparison figures, or explicitly state the range of masses where the band remains below all competing limits.
[Section 4.2, top right panel of Fig. 4.5] The comparison used to claim that the realistic propagation setup 'improves' the XMM-Newton constraints mixes two changes: the propagation model and the ambient photon maps. The text notes that 'the resultant bounds only differ slightly for DM masses above the some tens of MeV due to the use of older ambient SL and IR photon maps in Chapter 3,' but the plotted comparison is between the full new setup and the older Chapter 3 setup. To support the attribution of the improvement to reacceleration and diffusion, the same photon maps should be used in both calculations, or the figure should show the new propagation model with and without reacceleration while keeping all other inputs fixed.

minor comments (5)

[Section 1.1.2, Eq. (1.3)] The Coma cluster radius is written as R ? 0.3 pc; with roughly 800 galaxies and a measured velocity dispersion near 1000 km/s, the unit should presumably be Mpc. Please correct this typo.
[Section 2.2.3, Eq. (2.21)] The upper integration bound is written as 'mDM(/2)'; it should be mDM for annihilation and mDM/2 for decay. Please clarify the notation.
[Section 3.2, Eq. (3.16)] The one-sided statistic chi2_> is introduced for each dataset; please state explicitly that the 2-sigma condition chi2_> = 4 is an approximation that ignores correlations between energy bins and does not include nuisance parameters, and define the degrees of freedom used.
[Figure 4.2 caption] The caption uses 'va' rather than 'v_A' for the Alfven velocity; please make the notation uniform with Table 4.1 and the main text.
[Section 3.2, NuSTAR fields] The modeling of the NuSTAR blank-sky and GC fields as square annuli of inner size 1.5 degrees and outer size 3.5 degrees is an approximation. Please state the associated systematic uncertainty on the derived limits, or confirm quantitatively that it is negligible.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the X-ray and Voyager constraints follow from comparing independently predicted fluxes to external data, and the self-citations are provenance, not load-bearing evidence.

full rationale

The thesis's central derivations are self-contained against external benchmarks. In Chapter 3, the predicted X-ray flux is computed from particle-physics injection spectra, a chosen DM profile (NFW fiducial), ambient photon maps, and energy-loss functions, then compared to external X-ray datasets (XMM-Newton, NuSTAR, INTEGRAL, Suzaku) via the one-sided chi-square in Eq. 3.16; no free parameter of the DM model is fitted to those X-ray data. The DM profile normalization and the gas and radiation-field inputs are external, and their impact is explicitly varied in Figures 3.10 and 3.11. In Chapter 4, the propagation parameters, including the low-energy velocity index eta = -0.75 and Alfven velocity v_A = 13.4 km/s reported in Table 4.1, are taken from fits to AMS-02 B, Be, and Li secondary-to-primary ratios, which are independent of the DM X-ray signal; these parameters are then used to propagate DM-produced e± and compute ICS emission, so the resulting bounds are predictions rather than refits of the same data. The thesis acknowledges in Section 4.1.1 that 'different assumptions of the diffusion setup are able to reproduce the current local data,' which is a stated limitation on the low-energy extrapolation and affects the robustness of the sub-20 MeV improvement, but it is not circularity because the propagation model is not defined in terms of the DM constraints it is used to produce. The self-citations to the author's publications [1, 2, 3] serve as provenance for the thesis chapters; the relevant equations and computational steps are reproduced in the manuscript, so no load-bearing argument reduces to an unverified self-citation. No step was found where a prediction is equivalent by construction to its input.

Assumptions & free parameters 6 free parameters · 5 assumptions · 0 invented entities

The central results depend on a set of astrophysical and propagation parameters that are not derived in the thesis but taken from external fits or chosen as fiducial values. We list the main ones. No new particles or forces are introduced.

free parameters (6)

Alfven velocity v_A = 13.4 km/s (best fit; varied 0 to 40 km/s)
Controls the strength of cosmic-ray reacceleration, which drives the improvement of sub-GeV constraints in Chapter 4. Fitted to AMS-02 data in prior analysis by the authors.
Diffusion coefficient normalization D0 = 1.02e29 cm2/s
Sets the overall confinement of cosmic rays in the Galaxy. Taken from fits to AMS-02 boron-to-carbon ratios.
Diffusion spectral index delta = 0.49
Energy dependence of the diffusion coefficient at mid rigidities, from fits to AMS-02 data.
Velocity index eta = -0.75
Produces a strong rise in diffusion at sub-GeV energies. This parameter is central to the improved low-mass limits and is an extrapolation below the energies directly probed by AMS-02.
Halo height L = 8.0 kpc
Defines the vertical boundary of the diffusion zone and affects the confinement time of cosmic-ray electrons.
Local DM density rho_sun = 0.4 GeV/cm3 (NFW profile)
Normalizes all dark-matter-induced fluxes. Varied between profiles and normalizations in the uncertainty analysis.

assumptions (5)

domain assumption Dark matter is a collisionless particle with s-wave annihilation and xi = 1/2 for Dirac DM
Used to compute the source term for DM annihilation. The thesis notes that p-wave annihilation would weaken CMB bounds but not the X-ray bounds.
domain assumption The Milky Way DM density follows an NFW profile as fiducial choice
Section 3.3 shows that the choice of DM profile dominates the uncertainty for annihilating DM. Alternative profiles (Burkert, cNFW) are considered but NFW is used for the main results.
domain assumption Ambient photon fields (CMB, starlight, infrared) are known to within factor 2 (Chapter 3) or 30 percent (Chapter 4)
These fields set the ICS emissivity. The thesis varies their normalizations to assess the impact on the constraints.
ad hoc to paper The one-sided chi-square statistic comparing predicted DM flux to data without adding an astrophysical background yields conservative limits
Equation 3.16 defines the statistic. The authors argue that including a background would strengthen the limits, but this is a methodological choice, not a proven property.
domain assumption Propagation parameters fitted to AMS-02 data at higher energies apply at sub-GeV energies
Section 4.1.1 acknowledges that CR data below ~100 MeV are sparse and that the diffusion coefficient at these energies is uncertain. The main improvement of Chapter 4 depends on this extrapolation.

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Cite this review

Pith. "Pith review of Phenomenology of dark matter indirect detection." pith.science (2026). https://pith.science/paper/XHOFQ5XV

@misc{pith2026241111928,
  author       = {Pith},
  title        = {Pith review of: Phenomenology of dark matter indirect detection},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/XHOFQ5XV}},
  note         = {Machine review of arXiv:2411.11928}
}

read the original abstract

In this thesis, we present a comprehensive and pedagogical overview of dark matter (DM). Chapter 1 discusses the main evidences for its existence, its properties, and potential candidates. We then explore major detection strategies, with Chapter 2 specifically dedicated to indirect detection. In the following chapters, we study the emission of secondary photons resulting from the interaction between DM products and the Galactic environment. Chapters 3 and 4 focus on DM as sub-GeV particles, analysing how the DM-produced electrons and positrons interact with ambient photons to generate X-rays through inverse Compton scattering. Comparing the predicted spectra with data from X-ray observatories yields strong constraints on sub-GeV DM. Chapter 5 extends these techniques to the case of primordial black hole (PBH) evaporation, imposing significant limits on PBHs as potential DM candidates.

Figures

Figures reproduced from arXiv: 2411.11928 by the authors.

**Figure 1.1.** Left panel: Rotation curve of the galaxy NGC 6503 [7]. The dashed line repre [PITH_FULL_IMAGE:figures/full_fig_p021_1_1.png] view at source ↗

**Figure 1.2.** Left panel: Illustration of a gravitational lens system when the observer [PITH_FULL_IMAGE:figures/full_fig_p023_1_2.png] view at source ↗

**Figure 1.** , where the galaxy cluster MACS J1206 acts as the gravitational lens to some [PITH_FULL_IMAGE:figures/full_fig_p023_1.png] view at source ↗

Figures from the paper (45 more)

**Figure 1.3.** Figure 1.3: Observation of the Bullet Cluster by MAGELLAN in the optical range showing the position of individual galaxies (left panel) and by CHANDRA in the X-ray range showing the intracluster gas heating from the galaxy cluster collision (right panel). The green contours show…

**Figure 1.4.** Figure 1.4: Left panel: Sky map of the CMB temperature anisotropies measured by [PITH_FULL_IMAGE:figures/full_fig_p026_1_4.png]

**Figure 1.5.** Figure 1.5: Evolution of the cosmological parameters in the [PITH_FULL_IMAGE:figures/full_fig_p029_1_5.png]

**Figure 1.** Figure 1: summarises the evolution of DM abundance for the different aforementioned sce [PITH_FULL_IMAGE:figures/full_fig_p036_1.png]

**Figure 1.6.** Figure 1.6: Evolution of the DM abundance across the history of the Universe. The DM relic [PITH_FULL_IMAGE:figures/full_fig_p037_1_6.png]

**Figure 1.7.** Figure 1.7: Allowed mass range for DM, spanning from around [PITH_FULL_IMAGE:figures/full_fig_p038_1_7.png]

**Figure 1.8.** Figure 1.8: DD upper limits on the spin-independent DM-nucleon cross section as a function [PITH_FULL_IMAGE:figures/full_fig_p043_1_8.png]

**Figure 2.1.** Figure 2.1: Illustration of the principle behind DM ID, from DM annihilation or decay to the [PITH_FULL_IMAGE:figures/full_fig_p046_2_1.png]

**Figure 2.2.** Figure 2.2: Left panel: Plot of the possible Galactic DM profiles. Right panel: Values of [PITH_FULL_IMAGE:figures/full_fig_p049_2_2.png]

**Figure 2.3.** Figure 2.3: Spectra at production of p¯ (left panels), γ (middle panels) and e + (right panels) for DM particles with a mass of 100 GeV (top panels) or 100 TeV (bottom panels) annihilating in the following final states: e +e −, µ +µ −, τ +τ −, νe,µ,τ ν¯e,µ,τ , uu¯, b ¯b, tt¯, γγ…

**Figure 2.4.** Figure 2.4: Emission spectra of e + (left panel) and γ (right panel) from the evaporation of a single PBH, for masses varying between 1014.5 g and 1018 g. Computed using BlackHawk+Hazma. a position ⃗x in the Galaxy [105, 106] −∇· ⃗ Di∇⃗ fi + ⃗vcfi − ∂ ∂Ki K˙ ifi − K2 i Dp…

**Figure 2.5.** Figure 2.5: Illustration of the coordinate systems describing the position of a point in the [PITH_FULL_IMAGE:figures/full_fig_p058_2_5.png]

**Figure 2.6.** Figure 2.6: 54 [PITH_FULL_IMAGE:figures/full_fig_p060_2_6.png]

**Figure 2.7.** Figure 2.7: Illustration of the atmospheric opacity over the whole electromagnetic spec [PITH_FULL_IMAGE:figures/full_fig_p062_2_7.png]

**Figure 2.8.** Figure 2.8: Representation of the energy range (x-axis) and operation dates (y-axis) of a selection of radio, microwave (left panel), X- and γ-ray (right panel) telescopes and observatories. Taken from [127] [PITH_FULL_IMAGE:figures/full_fig_p063_2_8.png]

**Figure 2.9.** Figure 2.9: Sensitivities of a selection of X- and γ-ray observatories, illustrating the MeV gap. Adapted from [130]. MeV gap shown in [PITH_FULL_IMAGE:figures/full_fig_p064_2_9.png]

**Figure 3.** Figure 3: shows the spectrum of the number density per unit energy of all three components [PITH_FULL_IMAGE:figures/full_fig_p071_3.png]

**Figure 3.1.** Figure 3.1: Spectra of the photon number density per unit energy of ambient photons above [PITH_FULL_IMAGE:figures/full_fig_p072_3_1.png]

**Figure 3.2.** Figure 3.2: Illustration of some fluxes of hard X-rays from DM annihilation or decay, compared to the different datasets adopted in our analysis. In each panel we indicate the DM specifications (annihilation or decay channel, mass, annihilation cross section or decay rate, NFW …

**Figure 3.3.** Figure 3.3: Chart of the Galaxy in Galactic coordinates [PITH_FULL_IMAGE:figures/full_fig_p074_3_3.png]

**Figure 3.4.** Figure 3.4: Conservative constraints on annihilating DM from the different portions of the [PITH_FULL_IMAGE:figures/full_fig_p077_3_4.png]

**Figure 3.5.** Figure 3.5: Same as in Figure 3.4 but for decaying DM. [PITH_FULL_IMAGE:figures/full_fig_p078_3_5.png]

**Figure 3.6.** Figure 3.6: Summary of our conservative constraints on annihilating DM from each exper [PITH_FULL_IMAGE:figures/full_fig_p079_3_6.png]

**Figure 3.7.** Figure 3.7: Summary of our conservative constraints on decaying DM from each experiment [PITH_FULL_IMAGE:figures/full_fig_p079_3_7.png]

**Figure 3.8.** Figure 3.8: Final combined results for annihilating DM from this work (X [PITH_FULL_IMAGE:figures/full_fig_p080_3_8.png]

**Figure 3.9.** Figure 3.9: Final combined results for decaying DM from this work (X [PITH_FULL_IMAGE:figures/full_fig_p081_3_9.png]

**Figure 3.10.** Figure 3.10: Illustration of the impact of astrophysical uncertainties on the limits on DM [PITH_FULL_IMAGE:figures/full_fig_p082_3_10.png]

**Figure 3.11.** Figure 3.11: Illustration of the impact of total astrophysical uncertainties on DM annihilation [PITH_FULL_IMAGE:figures/full_fig_p082_3_11.png]

**Figure 4.1.** Figure 4.1: Comparison of the predicted e ± fluxes at Earth from DM annihilation to µ +µ − for mDM = mµ = 105.7 MeV (left panel) and mDM = 1 GeV (right panel) showing the impact of spatial diffusion and reacceleration. The solid lines describe the scenario including e ± diffusio…

**Figure 4.2.** Figure 4.2: Comparison of the predicted e ± flux from DM annihilating into e +e − with VOYAGER 1 data. We consider different values of mDM: 1 MeV (top left panel), 10 MeV (top right panel) and 100 MeV (bottom left) and 1 GeV (bottom right panel). We show the VOYAGER 1 data poin…

**Figure 4.3.** Figure 4.3: Comparison of XMM-NEWTON/MOS data in the third ring (12◦ < θ < 18◦ ) with the predicted DM-induced X-ray signal in that region, for DM with mDM = 10 MeV annihilating in e +e − (left panel) and with mDM ≃ mµ annihilating in µ +µ − (right panel) for different levels of…

**Figure 4.4.** Figure 4.4: Limits on the DM annihilation cross section [PITH_FULL_IMAGE:figures/full_fig_p091_4_4.png]

**Figure 4.5.** Figure 4.5: The top panels show the limits on annihilating DM from V [PITH_FULL_IMAGE:figures/full_fig_p092_4_5.png]

**Figure 4.6.** Figure 4.6: Comparison of the bounds on annihilating DM derived with the best-fit propaga [PITH_FULL_IMAGE:figures/full_fig_p094_4_6.png]

**Figure 4.7.** Figure 4.7: Comparison of the bounds on annihilating DM derived with the best-fit propaga [PITH_FULL_IMAGE:figures/full_fig_p094_4_7.png]

**Figure 5.1.** Figure 5.1: Spectra of secondary e ± (top panels) and photons (bottom panels) from the evaporation of a single BH with spin of a ⋆ = 0 (left panels) and a ⋆ = 0.9999 (right panels), for the following BH masses: M = 1014.5 g (red), 1015 g (orange), 1015.5 g (yellow), 1016 g (lime…

**Figure 5.2.** Figure 5.2: Evolution of the mass M of Schwarzschild BHs for different initial masses M0 at t = 0. The x-axis represents the time in terms of fractions of the age of the Universe and y-axis the BHs mass in terms of fractions of its initial mass. contribute to the low-energy bump…

**Figure 5.3.** Figure 5.3: Local e ± spectrum generated from PBH evaporation under different assumptions. Top left: Comparison of the spectrum for Schwarzschild PBH of different masses, assuming their mass distribution to be monochromatic. Top right: Comparison of the expected local e ± spectr…

**Figure 5.4.** Figure 5.4: Comparison of the predicted PBH-induced X-ray emission with diffuse X-ray data from XMM-NEWTON in a region close to the GC. We show the prediction is shown for different values of MPBH when the PBH mass distribution is monochromatic (top left panel), of a ⋆ (top righ…

**Figure 5.5.** Figure 5.5: Comparison of the expected longitude profile of the [PITH_FULL_IMAGE:figures/full_fig_p105_5_5.png]

**Figure 5.6.** Figure 5.6: Comparison of our limits on fPBH with other existing ones. The color of the lines represent the different probes used to set the constraints: green for the e ± measurements from VOYAGER 1, blue for X-ray diffuse observations from XMM-NEWTON, red for the 511 keV exces…

**Figure 5.7.** Figure 5.7: Limits on Schwarzschild PBHs we derive using V [PITH_FULL_IMAGE:figures/full_fig_p108_5_7.png]

**Figure 5.8.** Figure 5.8: Uncertainties in the limits we derive using V [PITH_FULL_IMAGE:figures/full_fig_p109_5_8.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

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