Hunting Dark Matter Lines in the Infrared Background with the James Webb Space Telescope

Dark matter particles with a mass around 1 eV can decay into near-infrared photons. Utilising available public blank sky observations from the NIRSpec IFU on the James Webb Space Telescope (JWST), we search for a narrow emission line due to decaying dark matter and derive leading constraints in the mass range 0.8-3 eV on the decay rate to photons, and more specifically, on the axion-photon coupling for the case of axion-like particles. We exclude $\tau < 6.7\cdot 10^{26}$ s at $m_{\rm DM} \simeq 0.9$ eV and, in the case of axions, $g_{a \gamma \gamma} > 9.4 \cdot 10^{-12}$ GeV$^{-1}$ for $m_a = 2.15$ eV. Our results do not rely on dedicated observations, rather we use blank sky observations intended for sky subtraction, and thus our reach may be automatically strengthened as JWST continues to observe.Comment: 12 pages, 2 figure

On the Neutrino and Gamma-Ray Emission from NGC 1068

IceCube has recently reported the detection of $\sim 1-10 \,{\rm TeV}$ neutrinos from the nearby active galaxy, NGC 1068. The lack of TeV-scale emission from this source suggests that these neutrinos are generated in the dense corona that surrounds NGC 1068's supermassive black hole. In this paper, we present a physical model for this source, including the processes of pair production, pion production, synchrotron, and inverse Compton scattering. We have also performed a new analysis of Fermi-LAT data from the direction of NGC 1068, finding that the gamma-ray emission from this source is very soft but bright at energies below $\sim 1 \, {\rm GeV}$. Our model can predict a gamma-ray spectrum that is consistent with Fermi-LAT observations, but only if the magnetic field within the corona of this active galactic nucleus (AGN) is quite high, namely $B\gtrsim 6 \, {\rm kG}$. To explain the observed neutrino emission, this source must accelerate protons with a total power that is comparable to its intrinsic X-ray luminosity. In this context, we consider two additional nearby active galaxies, NGC 4151 and NGC 3079, which have been identified as promising targets for IceCube

Integral X-ray constraints on sub-GeV Dark Matter

Light Dark Matter (DM), defined here as having a mass between 1 MeV and about 1 GeV, is an interesting possibility both theoretically and phenomenologically, at one of the frontiers of current progress in the field of DM searches. Its indirect detection via gamma-rays is challenged by the scarcity of experiments in the MeV-GeV region. We look therefore at lower-energy X-ray data from the Integral telescope, and compare them with the predicted DM flux. We derive bounds which are competitive with existing ones from other techniques. Crucially, we include the contribution from inverse Compton scattering on galactic radiation fields and the CMB, which leads to much stronger constraints than in previous studies for DM masses above 20 MeV.Comment: 16 pp+refs, 7 figs. v2: added comments on radiative decays and positron in-flight annihilation. Results unchanged. v3: comments added, on astrophysical uncertainties, on more aggressive bounds including background and on justifying adopted approximations. Results unchanged. v4: figure on astrophysical uncertainties added. Matches PRD version. v5: typo in the units of plots in fig. 2 and 3 fixe

Putting all the X in one basket: Updated X-ray constraints on sub-GeV Dark Matter

Sub-GeV dark matter particles can annihilate or decay producing e^\pm pairs which upscatter the low-energy photon fields in the Galaxy and generate an X-ray emission (via the Inverse Compton effect). Using X-ray data from Xmm-Newton, Integral, NuStar and Suzaku, we derive new constraints on this class of dark matter (DM). In the annihilation case, our new bounds are the strongest available for DM masses above 180 MeV, reaching < 10^-28 cm^3/s for m_DM ~ 1 GeV. In the decay case, our bounds are the strongest to date over a large fraction of the considered mass range, constraining tau > 10^28 s for m_DM ~ 1 GeV and improving by up to 3 orders of magnitude upon existing limits.Comment: 16 pages, 9 figure

Maximizing the general success of cecal intubation during propofol sedation in a multi-endoscopist academic centre

<p>Abstract</p> <p>Background</p> <p>Achieving the target of 95% colonoscopy completion rate at centres conducting colorectal screening programs is an important issue. Large centres and teaching hospitals employing endoscopists with different levels of training and expertise risk achieving worse results. Deep sedation with propofol in routine colonoscopy could maximize the results of cecal intubation.</p> <p>Methods</p> <p>The present study on the experience of a single centre focused on estimating the overall completion rate of colonoscopies performed under routine propofol sedation at a large teaching hospital with many operators involved, and on assessing the factors that influence the success rate of the procedure and how to improve this performance, analyzing the aspects relating to using of deep sedation. Twenty-one endoscopists, classified by their level of specialization in colonoscopic practice, performed 1381 colonoscopies under deep sedation. All actions needed for the anaesthesiologist to restore adequate oxygenation or hemodynamics, even for transient changes, were recorded.</p> <p>Results</p> <p>The "crude" overall completion rate was 93.3%. This finding shows that with routine deep sedation, the colonoscopy completion rate nears, but still does not reach, the target performance for colonoscopic screening programs, at centers where colonoscopists of difference experience are employed in such programs.</p> <p>Factors interfering with cecal intubation were: inadequate colon cleansing, endoscopists' expertise in colonoscopic practice, patients' body weight under 60 kg or age over 71 years, and the need for active intervention by the anaesthesiologist. The most favourable situation - a patient less than 71 years old with a body weight over 60 kg, an adequate bowel preparation, a "highly experienced specialist" performing the test, and no need for active anaesthesiological intervention during the procedure - coincided with a 98.8% probability of the colonoscopy being completed.</p> <p>Conclusions</p> <p>With routine deep sedation, the colonoscopy completion rate nears the target performance for colonoscopic screening programs, at centers where colonoscopists of difference experience are employed in such programs. Organizing the daily workload to prevent negative factors affecting the success rate from occurring in combination may enable up to 85% of incomplete procedures to be converted into successful colonoscopies.</p

Des rayons gamma aux ondes radio : recherche de la matière noire à travers le spectrum

Dark matter is one of the most fascinating open problems in modern physics. One interesting explanation is that it is composed of new particles, which are not included in the Standard Model. My doctoral thesis focuses on the indirect detection of these particles: the basic idea is that dark matter particles can annihilate or decay and produce cosmic rays detectable with our present and future telescopes. It is reasonable to think that particles of different masses can produce different signals, therefore the study of different messengers can provide additional information about their properties. I focused on studying gamma rays, X rays and radio waves that can be produced by particles with a mass range from MeV to TeV. In particular, I obtained the prediction of the cross-correlation signal between the extragalactic gamma-ray flux, measured by the Fermi Gamma-Ray Space Telescope, and the 21 cm line emitted by hydrogen in dark matter halos, observable with the MeerKAT and SKA radio telescopes. In addition, I obtained the limits on the effective annihilation cross-section of dark matter particles by comparing the X-ray flux measured by the INTEGRAL Space Telescope with the theoretical signal provided in the case of particles with a mass between 1 MeV and 5 GeV. Finally, a signal emerges from the radio maps of the GLEAM survey that seems to come from filaments of unknown origin. I gave an interpretation of this signal in terms of the synchrotron radiation produced by dark matter filaments.La matière noire est l’un des problèmes ouverts parmi les plus fascinants de la physique moderne. Une explication convaincante est qu’elle est composée de nouvelles particules, qui ne figurent pas dans le modèle standard. Ma thèse de doctorat porte sur la détection indirecte de ces particules : l’idée de base est que les particules de matière noire puissent s’annihiler ou se désintégrer et produire des rayons cosmiques détectables avec nos télescopes présents et futurs. Il est raisonnable de penser que des particules de masses différentes puissent produire des signaux différents, par conséquent l’étude de différents messagers peut fournir des informations complémentaires sur leurs propriétés. Je me suis concentrée sur l’étude des rayons gamma, des rayons X et des ondes radio qui peuvent être produits par des particules d’un intervalle de masse allant de MeV au TeV. En particulier, j’ai obtenu la prédiction du signal de corrélation croisée entre le flux gamma extragalactique, mesuré par le Fermi Gamma-Ray Telescope, et la raie de 21 cm émise par l’hydrogène dans les halos de matière noire, observable avec les radiotélescopes MeerKAT et SKA. De plus, j’ai obtenu les limites sur la section efficace d’annihilation des particules de matière noire en comparant le flux de rayons X mesuré par le télescope spatial INTEGRAL avec le signal théorique prévu dans le cas de particules d’une masse comprise entre 1 MeV et 5 GeV. Enfin, un signal émerge des cartes radio du survey GLEAM qui semble provenir de filaments d’origine inconnue. J’ai donné une interprétation de ce signal en termes de rayonnement synchrotron produit par les filaments de matière noire

Des rayons gamma aux ondes radio : recherche de la matière noire à travers le spectrum

La matière noire est l’un des problèmes ouverts parmi les plus fascinants de la physique moderne. Une explication convaincante est qu’elle est composée de nouvelles particules, qui ne figurent pas dans le modèle standard. Ma thèse de doctorat porte sur la détection indirecte de ces particules : l’idée de base est que les particules de matière noire puissent s’annihiler ou se désintégrer et produire des rayons cosmiques détectables avec nos télescopes présents et futurs. Il est raisonnable de penser que des particules de masses différentes puissent produire des signaux différents, par conséquent l’étude de différents messagers peut fournir des informations complémentaires sur leurs propriétés. Je me suis concentrée sur l’étude des rayons gamma, des rayons X et des ondes radio qui peuvent être produits par des particules d’un intervalle de masse allant de MeV au TeV. En particulier, j’ai obtenu la prédiction du signal de corrélation croisée entre le flux gamma extragalactique, mesuré par le Fermi Gamma-Ray Telescope, et la raie de 21 cm émise par l’hydrogène dans les halos de matière noire, observable avec les radiotélescopes MeerKAT et SKA. De plus, j’ai obtenu les limites sur la section efficace d’annihilation des particules de matière noire en comparant le flux de rayons X mesuré par le télescope spatial INTEGRAL avec le signal théorique prévu dans le cas de particules d’une masse comprise entre 1 MeV et 5 GeV. Enfin, un signal émerge des cartes radio du survey GLEAM qui semble provenir de filaments d’origine inconnue. J’ai donné une interprétation de ce signal en termes de rayonnement synchrotron produit par les filaments de matière noire.Dark matter is one of the most fascinating open problems in modern physics. One interesting explanation is that it is composed of new particles, which are not included in the Standard Model. My doctoral thesis focuses on the indirect detection of these particles: the basic idea is that dark matter particles can annihilate or decay and produce cosmic rays detectable with our present and future telescopes. It is reasonable to think that particles of different masses can produce different signals, therefore the study of different messengers can provide additional information about their properties. I focused on studying gamma rays, X rays and radio waves that can be produced by particles with a mass range from MeV to TeV. In particular, I obtained the prediction of the cross-correlation signal between the extragalactic gamma-ray flux, measured by the Fermi Gamma-Ray Space Telescope, and the 21 cm line emitted by hydrogen in dark matter halos, observable with the MeerKAT and SKA radio telescopes. In addition, I obtained the limits on the effective annihilation cross-section of dark matter particles by comparing the X-ray flux measured by the INTEGRAL Space Telescope with the theoretical signal provided in the case of particles with a mass between 1 MeV and 5 GeV. Finally, a signal emerges from the radio maps of the GLEAM survey that seems to come from filaments of unknown origin. I gave an interpretation of this signal in terms of the synchrotron radiation produced by dark matter filaments

Cosmic Coincidences of Primordial-Black-Hole Dark Matter

International audienceIf primordial black holes (PBHs) contribute more than 10% of the dark matter (DM) density, their energy density today is of the same order as that of the baryons. Such a cosmic coincidence might hint at a mutual origin for the formation scenario of PBHs and the baryon asymmetry of the Universe. Baryogenesis can be triggered by a sharp transition of the rolling rate of inflaton from slow-roll to (nearly) ultraslow-roll phases that produce large curvature perturbations for PBH formation in single-field inflationary models. We show that the baryogenesis requirement drives the PBH contribution to DM, along with the inferred PBH mass range, the resulting stochastic gravitational wave background frequency window, and the associated cosmic microwave background tensor-to-scalar ratio amplitude, into potentially observable regimes

Baryogenesis from ultra-slow-roll inflation

International audienceThe ultra-slow-roll (USR) inflation represents a class of single-field models with sharp deceleration of the rolling dynamics on small scales, leading to a significantly enhanced power spectrum of the curvature perturbations and primordial black hole (PBH) formation. Such a sharp transition of the inflationary background can trigger the coherent motion of scalar condensates with effective potentials governed by the rolling rate of the inflaton field. We show that a scalar condensate carrying (a combination of) baryon or lepton number can achieve successful baryogenesis through the Affleck-Dine mechanism from unconventional initial conditions excited by the USR transition. Viable parameter space for creating the correct baryon asymmetry of the Universe naturally incorporates the specific limit for PBHs to contribute significantly to dark matter, shedding light on the cosmic coincidence problem between the baryon and dark matter densities today