Using a novel 3D modeling approach, we determined the properties of the dark-matter halo of a dozen star-forming galaxies. We find that a significant fraction of the sample shows cored dark-matter profiles over the LCDM expectations (NFW). In addition, the cuspiness of the DM profiles is found to be a strong function of the recent star-formation activity. We will discuss on going work, new...
According to the LambdaCDM cosmology, present-day galaxies with stellar masses M>10^11 M_sun should contain a sizable fraction of dark matter within their stellar body. Models indicate that in massive early-type galaxies (ETGs) with M~1.5x10^11 Msun dark matter should account for ~15% of the dynamical mass within one effective radius (1 R_e) and for ~60% within 5 R_e. Most massive ETGs have...
Dark matter (DM) may be comprised of axionlike particles (ALPs) with couplings to photons and the standard model fermions. We study photon signals arising from cosmic ray (CR) electron scattering on background ALPs. For a range of masses we find that these bounds can place competitive new constraints on the ALP-electron coupling. In addition to current Fermi constraints, we also consider...
The flux of high-energy astrophysical γ rays is attenuated by the production of electron-positron pairs from scattering off of extragalactic background light (EBL). We use the most up-to-date information on galaxy populations to compute their contributions to the pair-production optical depth. We find that the optical depth inferred from γ-ray measurements exceeds that expected from galaxies...
Compact stars due to their enormous gravitational field can accumulate a sizable amount of dark matter in their interior. Depending on its nature, accumulated dark matter may affect the properties of neutron stars in quite different ways. I will give an overview of the impact of dark matter on various observable properties of neutron stars, i.e. the mass-radius relation, tidal deformability,...
Radio observations can provide useful information about the nature of dark matter: axion line, etc. In this talk, I will briefly review the relevant dark matter phenomenology in these frequencies and present fresh results from the stacked analysis of six dwarf spheroidal galaxies by the LOw Frequency ARray (LOFAR). This is the first time such an analysis has been carried out using LOFAR data....
Prompt cusps are the densest quasi-equilibrium dark matter objects; one forms at the instant of collapse within every isolated peak of the initial cosmological density field. They have power-law density profiles, ρ∝r−1.5 with central phase-space density set by the primordial velocity dispersion of the dark matter. At late times they account for ∼1% of the dark matter mass but for >90% of its...
Galaxy clusters are dark-matter-dominated systems enclosed in a volume that is a high-density microcosm of the rest of the universe. I will present the most recent results on the distribution of their gravitating and baryonic mass obtained from our XMM-Newton Multi-year Heritage and Large Programmes complemented with Planck maps (CHEX-MATE, X-COP), highlighting the role of X-ray and SZ data in...
There are several well-motivated scenarios in which dark matter could be present around black holes at a sufficient level to impact on the gravitational waveform of a merger. However, developing templates for the impact of such environments is challenging - in particular one issue that requires more attention is how to select and impose appropriate initial conditions that represent the state...
Ultralight dark matter is an exciting alternative to the standard cold dark matter paradigm, reproducing its large scale predictions, while solving most of its potential tension with small scale observations (like the "cusp-core" and "missing satellites" problems). If dark matter is made of some new light scalar particle, relatively dense and large structures are expected to form at the center...
Old isolated neutron stars have been gathering attention as targets to probe Dark Matter (DM) through temperature observations. DM will anomalously heat neutron stars through its gravitational capture and annihilation process, which predicts $T_s \simeq (1-3) \times 10^3$ K for $t > 10^{6}$ years. We may put constraints on DM-nucleon scattering cross section by finding even colder neutron...
