arXiv subjects

Emmanuel Moulin

Publications and source records attributed to Emmanuel Moulin.

42 records · Page 3Linked to original sources

arXiv2016

Dark Matter in $γ$ lines: Galactic Center vs dwarf galaxies

We provide CTA sensitivities to Dark Matter (DM) annihilation in $γ$-ray lines, from the observation of the Galactic Center (GC) as well as, for the first time, of dwarf Spheroidal galaxies (dSphs). We compare the GC reach with that of dSphs as a function of a putative core radius of the DM distribution, which is itself poorly known. We find that the currently best dSph candidates constitute a more promising target than the GC, for core radii of one to a few kpc. We use the most recent instrument response functions and background estimations by CTA, on top of which we add the diffuse photon component. Our analysis is of particular interest for TeV-scale electroweak multiplets as DM candidates, such as the supersymmetric Wino and the Minimal Dark Matter fiveplet, whose predictions we compare with our projected sensitivities.

astro-ph.HE↗

arXiv2015

Prospects for Annihilating Dark Matter in the inner Galactic halo by the Cherenkov Telescope Array

We compute the sensitivity to dark matter annihilations for the forthcoming large Cherenkov Telescope Array (CTA) in several primary channels and over a range of dark matter masses from 30 GeV up to 80 TeV. For all channels, we include inverse Compton scattering of e$^\pm$ by dark matter annihilations on the ambient photon background, which yields substantial contributions to the overall gamma-ray flux. We improve the analysis over previous work by: i) implementing a spectral and morphological analysis of the gamma-ray emission; ii) taking into account the most up-to-date cosmic ray background obtained from a full CTA Monte Carlo simulation and a description of the diffuse astrophysical emission; and iii) including the systematic uncertainties in the rich observational CTA datasets. We find that our spectral and morphological analysis improves the CTA sensitivity by roughly a factor 2. For the hadronic channels, CTA will be able to probe thermal dark matter candidates over a broad range of masses if the systematic uncertainties in the datasets will be controlled better than the percent level. For the leptonic modes, the CTA sensitivity will be well below the thermal value of the annihilation cross-section. In this case, even with larger systematics, thermal dark matter candidates up to masses of a few TeV will be easily studied.

astro-ph.HE↗

arXiv2012

Gamma ray constraints on Decaying Dark Matter

We derive new bounds on decaying Dark Matter from the gamma ray measurements of (i) the isotropic residual (extragalactic) background by Fermi and (ii) the Fornax galaxy cluster by HESS. We find that those from (i) are among the most stringent constraints currently available, for a large range of DM masses and a variety of decay modes, excluding half-lives up to ~10^26 to few 10^27 seconds. In particular, they rule out the interpretation in terms of decaying DM of the e^\pm spectral features in Pamela, Fermi and HESS, unless very conservative choices are adopted. We also discuss future prospects for CTA bounds from Fornax which, contrary to the present HESS constraints of (ii), may allow for an interesting improvement and may become better than those from the current or future extragalactic Fermi data.

astro-ph.CO↗

arXiv2011

Searches for dark matter subhaloes with wide-field Cherenkov telescope surveys

The presence of substructures in dark matter haloes is an unavoidable consequence of the cold dark matter paradigm. Indirect signals from these objects have been extensively searched for with cosmic rays and gamma-rays. At first sight, Cherenkov telescopes seem not very well suited for such searches, due to their small fields of view and the random nature of the possible dark matter substructure positions in the sky. However, with long enough exposure and an adequate observation strategy, the very good sensitivity of this experimental technique allows us to constrain particle dark matter models. We confront here the sensitivity map of the HESS experiment built out of their Galactic scan survey to the state-of-the-art cosmological N-body simulation Via Lactea II. We obtain competitive constraints on the annihilation cross section, at the level of 10^-24 -10^-23 cm^3s^-1. The results are extrapolated to the future Cherenkov Telescope Array, in the cases of a Galactic plane survey and of an even wider extragalactic survey. In the latter case, it is shown that the sensitivity of the Cherenkov Telescope Array will be sufficient to reach the most natural particle dark matter models.

astro-ph.HE↗

arXiv2010

The Cosmic Ray Lepton Puzzle

Recent measurements of cosmic ray electrons and positrons by PAMELA, ATIC, Fermi and HESS have revealed interesting excesses and features in the GeV-TeV range. Many possible explanations have been suggested, invoking one or more nearby primary sources such as pulsars and supernova remnants, or dark matter. Based on the output of the TANGO in PARIS --Testing Astroparticle with the New GeV/TeV Observations in Positrons And electRons : Identifying the Sources-- workshop held in Paris in May 2009, we review here the latest experimental results and we discuss some virtues and drawbacks of the many theoretical interpretations proposed so far.

astro-ph.HE↗

arXiv2004

MIMAC-He3: a new detector for non-baryonic dark matter search

The project of a micro-TPC matrix of cells of 3He for direct detection of non-baryonic dark matter is presented. The privileged properties of 3He for this detection are highlighted. The double detection: ionization-projection of tracks is explained and its rejection evaluated. The specific capabilities of this project with respect to other experiments are mentioned and its complementarities concerning the supersymmetric phenomenology explicitly showed.

astro-ph↗