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A new effective gravitational lensing approach to constrain dark matter

Thursday April 29, 2021
2:00 pm

 Presenter:  Birendra Dhanasingham (UNM)
 Series:  Center for Astrophysics Research and Technologies Seminar Series
 Abstract:  The distribution of dark matter on sub-galactic scales contains key information about its particle nature. Since dark matter does not interact electromagnetically like ordinary baryonic matter, we are unable to directly observe these enigmatic dark particles. However, dark matter betrays its existence by interacting gravitationally with luminous baryonic matter. It is thus important to develop new methods exploiting such gravitational effects to constrain its particle nature. In particular, strong gravitational lensing provides a powerful method of mapping the distribution of dark matter on small scales. In this work, we introduce an entirely new approach called “effective multiplane gravitational lensing” to study the collective effect of line-of-sight halos and main-lens dark matter substructure on extended lensed arcs. In this approach, the lens mapping between the source and image planes can be fully characterized by two “effective” lensing potentials encompassing the complete structure of the deflection field. Since line-of-sight halos and main-lens substructure contribute differently to each potential, this approach has the potential to distinguish these two contributions from each other, hence significantly improving constraint on dark matter from strong lensing. In this talk, I will present my work on the distinguishability of line-of-sight dark matter halos from main lens subhalos, which uses a power-spectrum-based approach. I will also discuss my other current and future projects to improve the concept of “effective multiplane gravitational lensing “ as a powerful method of revealing the nature of dark matter.
 Host:  Francis-Yan Cyr-Racine
 Location:  PAIS-2540, PAIS

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