Assuming that dark matter is dominated by WIMPs, it accretes by gravitational attraction and scattering over baryonic material and annihilates inside celestial objects, giving rise to a "dark ...luminosity" which may potentially affect the evolution of stars. We estimate the dark luminosity achieved by different kinds of stars in a halo with DM properties characteristic of the ones where the first star formation episode occurs. We find that both massive, metal-free and small, galactic-like stars can achieve dark luminosities comparable to or exceeding those due to their nuclear burning. This might have dramatic effects over the evolution of the very first stars, known as Population III.
The injection of secondary particles produced by Dark Matter (DM) annihilation at redshift100 <∼ z <∼ 1000 affects the process of recombination, leaving an imprint on Cosmic MicrowaveBackground (CMB) ...anisotropies. Here we provide a new assessment of the constraints set by CMBdata on the mass and self-annihilation cross-section of DM particles. Our new analysis includes themost recent WMAP (7-year) and ACT data, as well as an improved treatment of the time-dependentcoupling between the DM annihilation energy with the thermal gas. We show in particular that theimproved measurement of the polarization signal places already stringent constraints on light DMparticles, ruling out ‘thermal’ WIMPs with mass mχ <∼ 10 GeV
We present here a quantitative estimate of the impact of uncertainties of astrophysical nature on the determination of the dark matter distribution within our Galaxy, the Milky Way. Based on an ...update of a previous analysis, this work is motivated by recent new determinations of astrophysical quantities of relevance – such as the Galactic parameters (R0, V0) – from the GRAVITY collaboration and the GAIA satellite, respectively. We find that even with these state-of-the-art determination and a range of uncertainties – both statistical and systematic – much narrowed with respect to previous literature, the uncertainties on the dark matter distribution and their impact on searches of physics beyond the standard model stays sizable.
We present an analysis of the mass distribution in the region of the Galactic bulge, which leads to constraints on the total amount and distribution of Dark Matter (DM) therein. Our results – based ...on the dynamical measurement of the BRAVA collaboration – are quantitatively compatible with those of a recent analysis, and generalized to a vast sample of observationally inferred morphologies of the stellar components in the region of the Galactic bulge. By fitting the inferred DM mass to a generalized NFW profile, we find that cores (γ≲0.6) are forbidden only for very light configurations of the bulge, and that cusps (γ≳1.2) are allowed, but not necessarily preferred. Interestingly, we find that the results for the bulge region are compatible with those obtained with dynamical methods (based on the rotation curve) applied to outer regions of the Milky Way, for all morphologies adopted. We find that the uncertainty on the shape of the stellar morphology heavily affects the determination of the DM distribution in the bulge region, which is gravitationally dominated by baryons, adding up to the uncertainty on its normalization. The combination of the two hinders the actual possibility to infer sound conclusions about the distribution of DM in the region of the Galactic bulge, and only future observations of the stellar census and dynamics in this region will bring us closer to a quantitatively more definite answer.
We present galkin, a novel compilation of kinematic measurements tracing the rotation curve of our Galaxy together with a tool to treat the data. The compilation is optimised to Galactocentric radii ...between 3 and 20 kpc and includes the kinematics of gas, stars and masers in a total of 2780 measurements carefully collected from almost four decades of literature. A simple, user-friendly tool is provided to select, treat and retrieve the full database.
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