Stress-testing the cold dark matter model with gravitational lensing
Departments of Astronomy and Physics, Yale University, USA
We believe that in our universe dominated by dark matter and dark energy, the formation of galaxies and clusters, all structure formation, in fact, is driven by these unseen entities. This lambda cold dark matter model currently offers the best description for all the observational data in hand, despite the lack of detection of the putative dark matter particle. In this colloquium, I will present results from new high-precision tests of the granularity of the dark matter distribution predicted by this model derived from the recent exquisite data of cluster lenses imaged by the Hubble Space Telescope (HST). The combination of observed strong and weak gravitational lensing offers a very powerful tool to reconstruct the detailed distribution of dark matter in these massive cosmic objects. Comparison of the observational data with high resolution state-of-the-art simulations offers new, stringent tests of the cold dark matter model. With this unprecedented level of precision, stress-testing the theoretical model we find interesting new hints that reveal incongruences. Utilizing the substructure derived from the HST Frontier Fields data, I will present results of confronting the data with the suite of simulations and analytic calculations, and discuss their implications.
About the speaker: Priyamvada Natarajan is an astrophysicist and Professor at Yale University with a joint appointment in the Astronomy and Physics departments. She has made seminal contributions to our current understanding of the formation and growth of black holes and of the nature of dark matter by mapping it using gravitational lensing. Recipient of many awards & honors including the Guggenheim and Radcliffe fellowships, Professor Natarajan was until recently the chair of the Division of Astrophysics of The American Physical Society and currently serves on the national Astronomy & Astrophysics Advisory Committee that advises NASA, NSF and DoE. She is also the author of the critically acclaimed book /Mapping the Heavens: The Radical Scientific Ideas that Reveal the Cosmos/. She and her work have been featured in many news outlets including the New York Times, Quartz, BBC, CNN, New York Review of Books, PBS-NOVA, NPR, Science Friday and Quanta Magazine to name a few. Deeply interested in inter-disciplinary scholarship, she is at present the Director of the Franke Program in Science and the Humanities. Interested in the creative process in science and art, she collaborates with artists and her current VR experience piece LUNATICK with the sculptor Sir Antony Gormley and Acute Art UK currently on view at the Venice Biennale.