About Event

Wed 9 Nov 2022


This colloquium is hosted by STScI and will be held as a hybrid event.


3:00 PM - 4:00 PM EST


Astronomers have only observed 5% of the content of the Universe: the luminous (or baryonic) matter. The remaining 95% is invisible, consisting of so-called Dark Matter and Dark Energy. The nature of dark matter and dark energy is one of the most pressing fundamental questions in modern physics. This Dark Sector has remained impossible to detect directly, because neither component interacts with standard matter particles. Moreover many theories predict Dark Matter will remain fundamentally undetectable in terrestrial experiments, and can only be probed by astrophysical laboratories. 

Galaxy clusters, the most massive astrophysical objects observable, are ideal cosmic laboratories to study dark matter and dark energy. Indeed the number and mass distribution of galaxy clusters as a function of cosmic time is sensitive to the properties of dark energy, a repulsive force or modifications of the laws of gravity which could explain the acceleration of the expansion of the Universe. Furthermore, they are composed of ~85% of dark matter, making them the largest dark matter reservoirs in the Universe. Residing at the vertices of this Cosmic Web, clusters grow by steady accretion of matter from the surroundings, as well as by discrete mergers with nearby groups and clusters. Supported by simulations, this scenario regarding the total mass content and distribution in filaments and clusters remains largely untested.

While combining gravitational lensing regimes to map the total mass with multi-wavelength imaging and spectroscopy of clusters and their galaxies, one can thus study the dynamical scenarios in place within these clusters, trace the substructures engaged in these processes, and constrain evolution and formation theories. During this talk, I will present an overview of the astrophysical searches for dark matter my group is undertaking, and will discuss the first results obtained with the uniquely powerful James Webb Space Telescope which first science observations were released in July 2022.

Speaker: Mathilde Jauzac  (Durham University)


All 2022 Fall Colloquium talks are held on Wednesday at 3:00 PM.  You may join the colloquium in person at STScI’s John N. Bahcall Auditorium or virtually or at the links listed below. 

Please direct questions or comments to contact above. The Fall Colloquium Committee members are: JHU Members: Kevin Schlaufman, Co-Chair, Ethan Vishniac, Arshia Jacob and STScI Members: Joel Green, Co-chair, Armin Rest, Co-chair and Andreea Petric.