arXiv subjects

Mattia Di Mauro

Publications and source records attributed to Mattia Di Mauro.

77 records · Page 5Linked to original sources

arXiv2015

AMS-02 electrons and positrons: astrophysical interpretation and Dark Matter constraints

We present here a quantitative analysis of the recent AMS-02 data with the purpose of investigating the interplay between astrophysical sources and Dark Matter in their interpretation. First, we show that AMS-02 leptonic measurements are in a remarkably good agreement with the hypothesis that all electrons and positrons are the outcome of primary or secondary astrophysical processes. Then, we add Dark Matter to the picture, in order to establish which are the informations on its annihilation cross section (or lifetime) that can be inferred by fitting AMS-02 data within a scenario in which Dark Matter and astrophysical sources jointly contribute to the different leptonic observables. In particular, by performing a Markov Chain Monte Carlo sampling of the parameters space of the theory, we attempt at characterizing the significance of a possible Dark Matter contribution to the observed data and we derive robust upper limits on the Dark Matter annihilation/decay rate.

astro-ph.HE↗

arXiv2015

Isotropic diffuse gamma-ray background: unveiling Dark Matter components beyond the contribution of astrophysical sources

We present the first interpretation of the new isotropic diffuse gamma-ray background (IGRB), measured by the Fermi Large Area Telescope (LAT), based on a statistical analysis. We demonstrate that the gamma-ray emission from unresolved active galactic nuclei and star forming galaxies is consistent with the Fermi-LAT IGRB data within the uncertainties both on the choice of the Galactic diffuse emission model and on the gamma-ray emission mechanism of these sources. Furthermore, adding to the extragalactic sources the contribution from a smooth Galactic halo of annihilating weakly interacting dark matter (DM) particles, we are able to set stringent limits on the DM annihilation cross section. Finally, we demonstrate that the addition of DM can significantly improve the fit to IGRB data.

astro-ph.HE↗

arXiv2014

Gamma rays from Galactic pulsars

Gamma rays from young pulsars and milli-second pulsars are expected to contribute to the diffuse gamma-ray emission measured by the {\it Fermi} Large Area Telescope (LAT) at high latitudes. We derive the contribution of the pulsars undetected counterpart by using information from radio to gamma rays and we show that they explain only a small fraction of the isotropic diffuse gamma-ray background.

astro-ph.HE↗

arXiv2014

Fermi-LAT gamma-ray anisotropy and intensity explained by unresolved Radio-Loud Active Galactic Nuclei

Radio-loud active galactic nuclei (AGN) are expected to contribute substantially to both the intensity and anisotropy of the isotropic gamma-ray background (IGRB). In turn, the measured properties of the IGRB can be used to constrain the characteristics of proposed contributing source classes. We consider individual subclasses of radio-loud AGN, including low-, intermediate-, and high-synchrotron-peaked BL Lacertae objects, flat-spectrum radio quasars, and misaligned AGN. Using updated models of the gamma-ray luminosity functions of these populations, we evaluate the energy-dependent contribution of each source class to the intensity and anisotropy of the IGRB. We find that collectively radio-loud AGN can account for the entirety of the IGRB intensity and anisotropy as measured by the Fermi Large Area Telescope (LAT). Misaligned AGN provide the bulk of the measured intensity but a negligible contribution to the anisotropy, while high-synchrotron-peaked BL Lacertae objects provide the dominant contribution to the anisotropy. In anticipation of upcoming measurements with the Fermi-LAT and the forthcoming Cherenkov Telescope Array, we predict the anisotropy in the broader energy range that will be accessible to future observations.

astro-ph.HE↗

arXiv2014

Constraining dark matter annihilation with the isotropic $γ$-ray background: updated limits and future potential

The nature of the Isotropic $γ$-ray Background (IGRB) measured by the Large Area Telescope (LAT) on the Fermi $γ$-ray space Telescope ({\it Fermi}) remains partially unexplained. Non-negligible contributions may originate from extragalactic populations of unresolved sources such as blazars, star-forming galaxies or galactic milli-second 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 (l.o.s.) 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 ($>10^\circ$) 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 {\it 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.

astro-ph.CO↗