Search Publications
Light neutralino dark matter in the next-to-minimal supersymmetric standard model
Hooper, Dan; Gunion, John F.; McElrath, Bob
Neutralino dark matter is generally assumed to be relatively heavy, with a mass near the electroweak scale. This does not necessarily need to be the case, however. In the next-to-minimal supersymmetric standard model (NMSSM) and other supersymmetric models with an extended Higgs sector, a very light CP-odd Higgs boson can naturally arise making it…
Direct x-ray constraints on sterile neutrino warm dark matter
Beacom, John F.; Watson, Casey R.; Yüksel, Hasan +1 more
Warm dark matter might more easily account for small scale clustering measurements than the heavier particles typically invoked in Λ cold dark matter (ΛCDM) cosmologies. In this paper, we consider a ΛWDM cosmology in which sterile neutrinos νs, with a mass ms of roughly 1 100 keV, are the dark matter. We use the diffuse x-ray…
Restrictions on parameters of sterile neutrino dark matter from observations of galaxy clusters
Neronov, A.; Boyarsky, A.; Ruchayskiy, O. +1 more
We find restrictions on the mass and mixing angle of the dark matter sterile neutrinos using x-ray observations of Coma and Virgo galaxy clusters with XMM-Newton satellite. In the absence of clearly detectable line, we present detailed analysis of various methods of putting restrictions on mass and mixing angle of sterile neutrino. Our analysis pr…
Continuum γ-ray emission from light dark matter positrons and electrons
Schanne, S.; Sizun, P.; Cassé, M.
The annihilation of light dark matter was recently advocated as a possible explanation of the large positron injection rate at the Galactic center deduced from observations by the SPI spectrometer aboard INTEGRAL. The modelling of internal Bremsstrahlung and in-flight annihilation radiations associated to this process drastically reduced the mass …
Constraint on the post-Newtonian parameter γ on galactic size scales
Bolton, Adam S.; Burles, Scott; Rappaport, Saul
We constrain the post-Newtonian gravity parameter γ on kiloparsec scales by comparing the masses of 15 elliptical lensing galaxies from the Sloan Lens ACS Survey as determined in two independent ways. The first method assumes only that Newtonian gravity is correct and is independent of γ, while the second uses gravitational lensing which depends o…
Soft gamma-ray background and light dark matter annihilation
Fayet, Pierre; Cordier, Bertrand; Teyssier, Romain +4 more
The bulk of the extragalactic background between 10 keV and 10 GeV is likely to be explained by the emission of Seyfert galaxies, type Ia supernovae, and blazars. However, as revealed by the INTEGRAL satellite, the bulge of our galaxy is an intense source of a 511 keV gamma-ray line, indicating the production of a large number of positrons that an…
Hubble imaging excludes cosmic string lens
Hogan, Craig J.; Agol, Eric; Plotkin, Richard M.
The galaxy image pair Capodimonte-Sternberg-Lens Candidate no. 1 (CSL-1) has been a leading candidate for a cosmic string lens. High quality imaging data from the Hubble Space Telescope presented here show that it is not a lens but a pair of galaxies. The galaxies show different orientations of their principal axes, not consistent with any lens mo…