Publications (42)
Sterile neutrinos with eV masses in cosmology -- how disfavoured exactly?
Jan Hamann, Steen Hannestad, Georg G. Raffelt +1
We study cosmological models that contain sterile neutrinos with eV-range masses as suggested by reactor and short-baseline oscillation data. We confront these models with both pre…
A Minkowski Functional Analysis of the Cosmic Microwave Background Weak Lensing Convergence
Jan Hamann, Yuqi Kang
Minkowski functionals are summary statistics that capture the geometric and morphological properties of fields. They are sensitive to all higher order correlations of the fields an…
Precise measurements of inflationary features with 21 cm observations
Yidong Xu, Jan Hamann, Xuelei Chen
Future observations of 21~cm emission using HI intensity mapping will enable us to probe the large scale structure of the Universe over very large survey volumes within a reasonabl…
Removing the mask -- reconstructing a scalar field on the sphere from a masked field
Jan Hamann, Quoc Thong Le Gia, Ian H. Sloan +1
The paper analyses a spectral approach to reconstructing a scalar field on the sphere, given only information about a masked version of the field together with precise information…
How robust are inflation model and dark matter constraints from cosmological data?
Jan Hamann, Steen Hannestad, Martin S. Sloth +1
High-precision data from observation of the cosmic microwave background and the large scale structure of the universe provide very tight constraints on the effective parameters tha…
Constraining primordial tensor features with the anisotropies of the Cosmic Microwave Background
Jan Hamann, Ameek Malhotra
It is commonly assumed that the stochastic background of gravitational waves on cosmological scales follows an almost scale-independent power spectrum, as generically predicted by…