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Papers by Joseph Silk
Proceedings of the International Astronomical Union
Models of structure formation based on cold dark matter predict that most of the small dark matte... more Models of structure formation based on cold dark matter predict that most of the small dark matter haloes that first formed at high redshift would have merged into larger systems by the present epoch. Substructure in present-day haloes preserves the remains of these ancient systems, providing the only direct information we may ever have about the low-mass end of the power spectrum. I describe some recent attempts to model halo substructure down to very small masses, using a semi-analytic model of halo formation. I make a preliminary comparison between the model predictions, observations of substructure in lensed systems, and the properties of local satellite galaxies.
Physical Review Letters, 2013
We investigate the possibility of fitting the putative spectrum of gamma rays from annihilating d... more We investigate the possibility of fitting the putative spectrum of gamma rays from annihilating dark matter at the galactic center by a superexponential template. By generating and analyzing mock data for several ongoing and future experiments (HESS, CTA, and DMA), we find that the preference for a superexponential template (over an exponential) is especially strong for dark matter annihilating to τ(+)τ(-) and μ(+)μ(-) relative to other annihilation channels.
Proceedings of the International Astronomical Union
Models of structure formation based on cold dark matter predict that most of the small dark matte... more Models of structure formation based on cold dark matter predict that most of the small dark matter haloes that first formed at high redshift would have merged into larger systems by the present epoch. Substructure in present-day haloes preserves the remains of these ancient systems, providing the only direct information we may ever have about the low-mass end of the power spectrum. I describe some recent attempts to model halo substructure down to very small masses, using a semi-analytic model of halo formation. I make a preliminary comparison between the model predictions, observations of substructure in lensed systems, and the properties of local satellite galaxies.
Physical Review Letters, 2013
We investigate the possibility of fitting the putative spectrum of gamma rays from annihilating d... more We investigate the possibility of fitting the putative spectrum of gamma rays from annihilating dark matter at the galactic center by a superexponential template. By generating and analyzing mock data for several ongoing and future experiments (HESS, CTA, and DMA), we find that the preference for a superexponential template (over an exponential) is especially strong for dark matter annihilating to τ(+)τ(-) and μ(+)μ(-) relative to other annihilation channels.