1704.00069
100 Years of the Cosmological Constant: what's next?
Lahav
The Cosmological Constant Lambda, in different incarnations, has been with us for 100 years. Many surveys of DE are underway, indicating so far that the data are consistent with a dark energy equation of state of w=-1, i.e. a Lambda term in einstein's equation, although time variation of w is not yet ruled out. The balls in now back in the theoreticians' court, to explain the physical meaning of Lambda. Discuss sociological aspects of this field, in particular to what extent the agreement on the cold dark matter + Lambda concordance model is a result of the globalization of research and over-communication.
1704.00258
Quantifying systematics from the shear inversion on weak-lensing peak counts
Lin, Kilbinger
WL peak counts provide a straightforward way to constrain cosmology and results have been shown promising. However, the importance of understanding and dealing with systematics increases as data quality reaches an unprecedented level. One of the sources of systematics is the convergence-shear inversion. This effect, inevitable from observations, is usually neglected by theoretical peak models. Thus, it could have an impact on cosmological results. In this letter, study the bias from neglecting they version and find it small but not negligible. The cosmological dependence of this bias is difficult to model and depends on the filter size. Also show the evolution of parameter constraints. Although weak biases arise in individual peak bins, the bias can reach 2sigma for the DE equation of state w0. Therefore, suggest that the inversion cannot be ignored and that inversion-free approaches, such as aperture mass, would be a more suitable tool to study weak-lensing peak counts.
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